Horticulturae

12 pages, 1544 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Spaceflight on Tomato Seed Quality and Biochemical Characteristics of Mature Plants

by Elena Dzhos, Nadezhda Golubkina, Marina Antoshkina, Irina Kondratyeva, Andrew Koshevarov, Anton Shkaplerov, Tatiana Zavarykina, Galina Nechitailo and Gianluca Caruso

Horticulturae 2021, 7(5), 89; https://doi.org/10.3390/horticulturae7050089 - 22 Apr 2021

Cited by 11 | Viewed by 3553

Abstract

Intensive space exploration includes profound investigations on the effect of weightlessness and cosmic radiation on plant growth and development. Tomato seeds are often used in such experiments though up to date the results have given rather vague information about biochemical changes in mature [...] Read more.

Intensive space exploration includes profound investigations on the effect of weightlessness and cosmic radiation on plant growth and development. Tomato seeds are often used in such experiments though up to date the results have given rather vague information about biochemical changes in mature plants grown from seeds subjected to spaceflight. The effect of half a year of storage in the International Space Station (ISS) on tomato seeds (cultivar Podmoskovny ranny) was studied by analyzing the biochemical characteristics and mineral content of mature plants grown from these seeds both in greenhouse and field conditions. A significant increase was recorded in ascorbic acid, polyphenol and carotenoid contents, and total antioxidant activity (AOA), with higher changes in the field conditions compared to greenhouse. Contrary to control plants, the ones derived from space-stored seeds demonstrated a significant decrease in root AOA. The latter plants also showed a higher yield, but lower content of fruit dry matter, sugars, total dissolved solids and organic acids. The fruits of plants derived from space-stored seeds demonstrated decreased levels of Fe, Cu and taste index. The described results reflect the existence of oxidative stress in mature tomato plants as a long-term consequence of the effect of spaceflight on seed quality, whereas the higher yield may be attributed to genetic modifications. Full article

(This article belongs to the Special Issue Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Green, Red and Flowering Plants)

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10 pages, 2188 KiB

Open AccessEditor’s ChoiceArticle

A Quantitative Management of Potassium Supply for Hydroponic Production of Low-Potassium Cherry-Type Tomato Fruit for Chronic Kidney Disease Patients

by Satoru Tsukagoshi, Miho Aoki, Masahumi Johkan, Masaaki Hohjo and Toru Maruo

Horticulturae 2021, 7(4), 87; https://doi.org/10.3390/horticulturae7040087 - 19 Apr 2021

Cited by 4 | Viewed by 4174

Abstract

Chronic kidney disease (CKD) has been a global health problem in recent years. CKD patients often restrict their potassium (K) intake to avoid the high risk of hyperkalemia. In this study, quantitative K management in hydroponics was adopted to produce low K cherry-type [...] Read more.

Chronic kidney disease (CKD) has been a global health problem in recent years. CKD patients often restrict their potassium (K) intake to avoid the high risk of hyperkalemia. In this study, quantitative K management in hydroponics was adopted to produce low K cherry-type tomato (Solanum lycopersicom L.) fruit. The total quantity of K supply per plant during the cultivation was 7.2 g (1 K), 3.6 g (1/2 K), 1.8 g (1/4 K), 0.9 g (1/8 K) and 0.6 g (1/12 K), respectively. The total fruit yield decreased to about 75% at 1/2 K and 58% at 1/12 K compared to 1 K. The fruit K content was lower in 1/4 K, 1/8 K and 1/12 K than in 1 K and 1/2 K, and the fruit from 1/8 K and 1/12 K achieved below 100 mg 100 g⁻¹ FW of K. Total soluble solid content (Brix) was 7–8% in 1 K and 1/4 K but was lower in 1/8 K and 1/12 K. Fruit acid content decreased to 87% in 1/2 K to 70% in 1/4 K and 1/8 K, and to 57% in 1/12 K of 1 K. In conclusion, quantitative K management in hydroponics is expected to produce low K tomato fruit. Fruit K content of approximately 100 mg.100 g⁻¹ FW was achieved when the quantity of K supply was 1/4 K and 1/8 K, with a relatively smaller effect on fruit yield, Brix and acid content. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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14 pages, 4565 KiB

Open AccessEditor’s ChoiceArticle

A Transcriptomic Analysis of Gene Expression in Chieh-Qua in Response to Fusaric Acid Stress

by Min Wang, Wenrui Liu, Jinqiang Yan, Piaoyun Sun, Feng Chen, Biao Jiang, Dasen Xie, Yu’e Lin, Qingwu Peng and Xiaoming He

Horticulturae 2021, 7(4), 88; https://doi.org/10.3390/horticulturae7040088 - 19 Apr 2021

Cited by 4 | Viewed by 3202

Abstract

Fusarium wilt results in undesirable effects on the quality and production of chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How). Fusaric acid (FA), a secondary metabolite of biotin produced by pathogens of genus Fusarium, induced resistant responses in chieh-qua; however, the physiological and [...] Read more.

Fusarium wilt results in undesirable effects on the quality and production of chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How). Fusaric acid (FA), a secondary metabolite of biotin produced by pathogens of genus Fusarium, induced resistant responses in chieh-qua; however, the physiological and molecular mechanism(s) of FA resistance remains largely unknown. In our study, ‘A39’ (FA-resistant cultivar) exhibited decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) enzyme activity when exposed to FA compared with ‘H5’ (FA-susceptible cultivar). More apoptosis cells existed in ‘H5’ than ‘A39’ after 2 days of FA treatment. RNA-seq results revealed that a total of 2968 and 3931 differentially expressed genes (DEGs) were detected under normal conditions (1562 up-regulated and 1406 down-regulated) and FA treatment (2243 up-regulated and 1688 down-regulated), respectively. Interestingly, DEGs associated with pathogen-related protein and ethylene (ET) biosynthesis and signal pathways were most significantly changed during FA stress. Notably, several crucial genes encoding pathogenesis-related protein (CL4451.Contig2, CL2175.Contig4), peroxidase (Unigene49615 and CL11695.Contig2), and ET-responsive transcription factors (TFs) (CL9320.Contig1, CL9849.Contig3, CL6826.Contig2, CL919. Contig6, and CL518.Contig7) were specifically induced after FA treatment. Collectively, the study provides molecular data for isolating candidate genes involved in FA resistance, especially ET related genes in chieh-qua. Full article

(This article belongs to the Special Issue Natural Actives Molecules: A Sustainable Solution to Fight against Diseases and Pests of Vegetable and Fruit Crops Ⅱ)

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13 pages, 2620 KiB

Open AccessEditor’s ChoiceArticle

Exogenous EBR Ameliorates Endogenous Hormone Contents in Tomato Species under Low-Temperature Stress

by Parviz Heidari, Mahdi Entazari, Amin Ebrahimi, Mostafa Ahmadizadeh, Alessandro Vannozzi, Fabio Palumbo and Gianni Barcaccia

Horticulturae 2021, 7(4), 84; https://doi.org/10.3390/horticulturae7040084 - 17 Apr 2021

Cited by 48 | Viewed by 4741

Abstract

Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant [...] Read more.

Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant enzyme activity, and transcription of several cold-responsive genes, under low-temperature stress (9 °C) in two different tomato species (cold-sensitive and cold-tolerant species). Results indicated that the treatment with exogenous EBR increases the content of gibberellic acid (GA3) and indole-3-acetic acid (IAA), whose accumulation is reduced by low temperatures in cold-sensitive species. Furthermore, the combination or contribution of BR and abscisic acid (ABA) as a synergetic interaction was recognized between BR and ABA in response to low temperatures. The content of malondialdehyde (MDA) and proline was significantly increased in both species, in response to low-temperature stress; however, EBR treatment did not affect the MDA and proline content. Moreover, in the present study, the effect of EBR application was different in the tomato species under low-temperature stress, which increased the catalase (CAT) activity in the cold-tolerant species and increased the glutathione peroxidase (GPX) activity in the cold-sensitive species. Furthermore, expression levels of cold-responsive genes were influenced by low-temperature stress and EBR treatment. Overall, our findings revealed that a low temperature causes oxidative stress while EBR treatment may decrease the reactive oxygen species (ROS) damage into increasing antioxidant enzymes, and improve the growth rate of the tomato by affecting auxin and gibberellin content. This study provides insight into the mechanism by which BRs regulate stress-dependent processes in tomatoes, and provides a theoretical basis for promoting cold resistance of the tomato. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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15 pages, 1033 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Peach, Apple, and Pear Fruit Quality: To Peel or Not to Peel?

by Michail Michailidis, Evangelos Karagiannis, Elpida Nasiopoulou, Christina Skodra, Athanassios Molassiotis and Georgia Tanou

Horticulturae 2021, 7(4), 85; https://doi.org/10.3390/horticulturae7040085 - 17 Apr 2021

Cited by 26 | Viewed by 6580

Abstract

The nutritional value of the peeled and unpeeled fruit (peel plus flesh tissues) was studied using four peach (Prunus persica L.; Red Heaven, Maria Blanca, Big Top, and Queen Giant), two pear (Pyrus communis L.; Santa Maria, Pyrus pyrifolia N.; Nashi), [...] Read more.

The nutritional value of the peeled and unpeeled fruit (peel plus flesh tissues) was studied using four peach (Prunus persica L.; Red Heaven, Maria Blanca, Big Top, and Queen Giant), two pear (Pyrus communis L.; Santa Maria, Pyrus pyrifolia N.; Nashi), and three apple (Malus domestica Borkh.; Gala, Granny Smith, and Red Chief) cultivars. Based on principal components analysis (PCA) models, there was a clear differentiation among the cultivars’ and the peeled fruits’ nutritional characteristics in comparison to the unpeeled ones. Increased antioxidant capacity and content of total phenols and flavonoids of peaches (Red Heaven and Maria Blanca) versus nectarines (Big Top and Queen Giant) were recorded. In contrast, nectarines were characterized by higher hydroxycinnamates and dry matter. The apples’ cultivar Granny Smith exhibited a high level of titratable acidity (TA), while the Gala displayed a high level of soluble solids concentration (SSC), carotenoids, dry matter, hydroxycinnamic acids, and flavonols at the unpeeled fruit, whereas the Red Chief by increased anthocyanins, antioxidant capacity, total phenols, and flavonoids. Nashi pears with peel were more beneficial due to the strong skin contribution in the fruits’ beneficial compounds content. The peel of the Granny Smith cultivar was associated with an increased level of P, K, Ca, and Mg, whereas that of Red Chief with increased anthocyanins and Mg content. Full article

(This article belongs to the Special Issue Improving Quality of Fruit)

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13 pages, 3215 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Effects of Post-Harvest Treatments on the Quality of Agastache aurantiaca Edible Flowers

by Ilaria Marchioni, Rosanna Dimita, Giovanni Gioè, Luisa Pistelli, Barbara Ruffoni, Laura Pistelli and Basma Najar

Horticulturae 2021, 7(4), 83; https://doi.org/10.3390/horticulturae7040083 - 15 Apr 2021

Cited by 11 | Viewed by 3886

Abstract

Agastache spp. are used as ornamental plants for their pleasant aroma and the different colors of flowers. Nowadays, their edible flowers have become attractive for their nutraceutical properties. Post-harvest treatment appears as a crucial point to avoid impairment of the nutraceutical compounds and [...] Read more.

Agastache spp. are used as ornamental plants for their pleasant aroma and the different colors of flowers. Nowadays, their edible flowers have become attractive for their nutraceutical properties. Post-harvest treatment appears as a crucial point to avoid impairment of the nutraceutical compounds and aroma, so different treatments were tested to analyze their effect on the bioactive metabolites and volatilome. Results indicated that freeze-drying was the best solution to prolong the shelf life of these flowers. The use of high temperatures (50, 60, 70 °C) led to altered the composition of antioxidant compounds (phenolic compounds, flavonoids, anthocyanins, carotenoids). Air-drying at 30 °C was a reasonable method, even though time consuming. Concerning the aroma profile, all samples were dominated by oxygenated monoterpene compounds. Pulegone was the main or one of the major constituents of all samples together with p-menthone. Gas Chromatography-Mass Spectrometry results showed a correlation between the temperature and the number of identified compounds. Both fresh and freeze-dried samples evidenced a lesser number (10 and 19, respectively); when the temperature raised, the number of identified constituents increased. Statistical analyses highlighted significant differences between almost all aromatic compounds, even if both Principal Component and Hierarchical Cluster analyses differed at 60 and 70 °C and from the other treatments. Full article

(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)

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14 pages, 2778 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Pre-Harvest Supplemental UV-A/Blue and Red/Blue LED Lighting on Lettuce Growth and Nutritional Quality

by Triston Hooks, Joseph Masabni, Ling Sun and Genhua Niu

Horticulturae 2021, 7(4), 80; https://doi.org/10.3390/horticulturae7040080 - 14 Apr 2021

Cited by 21 | Viewed by 5426

Abstract

Blue light and ultra-violet (UV) light have been shown to influence plant growth, morphology, and quality. In this study, we investigated the effects of pre-harvest supplemental lighting using UV-A and blue (UV-A/Blue) light and red and blue (RB) light on growth and nutritional [...] Read more.

Blue light and ultra-violet (UV) light have been shown to influence plant growth, morphology, and quality. In this study, we investigated the effects of pre-harvest supplemental lighting using UV-A and blue (UV-A/Blue) light and red and blue (RB) light on growth and nutritional quality of lettuce grown hydroponically in two greenhouse experiments. The RB spectrum was applied pre-harvest for two days or nights, while the UV-A/Blue spectrum was applied pre-harvest for two or four days or nights. All pre-harvest supplemental lighting treatments had a same duration of 12 h with a photon flux density (PFD) of 171 μmol m⁻² s⁻¹. Results of both experiments showed that pre-harvest supplemental lighting using UV A/Blue or RB light can increase the growth and nutritional quality of lettuce grown hydroponically. The enhancement of lettuce growth and nutritional quality by the pre-harvest supplemental lighting was more effective under low daily light integral (DLI) compared to a high DLI and tended to be more effective when applied during the night, regardless of spectrum. Full article

(This article belongs to the Special Issue Smart Farming Techniques for Protected Horticulture Facilities)

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12 pages, 1264 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Water-Yield Relationship and Vegetative Growth of Wonderful Young Pomegranate Trees under Deficit Irrigation Conditions in Southeastern Italy

by Annalisa Tarantino, Laura Frabboni and Grazia Disciglio

Horticulturae 2021, 7(4), 79; https://doi.org/10.3390/horticulturae7040079 - 12 Apr 2021

Cited by 10 | Viewed by 3309

Abstract

This investigation was carried out through three successive seasons (2017, 2018, and 2019) on young pomegranate trees of the Wonderful cultivar to study the effect of four different irrigation treatments (100%, 75%, 50%, and 25% of crop evapotranspiration—ETc) on vegetative growth [...] Read more.

This investigation was carried out through three successive seasons (2017, 2018, and 2019) on young pomegranate trees of the Wonderful cultivar to study the effect of four different irrigation treatments (100%, 75%, 50%, and 25% of crop evapotranspiration—ETc) on vegetative growth and the water–yield relationship. The study was conducted in Foggia (Apulia region, Southern Italy), an agricultural area characterized by strong wind speeds and scarce water resources. The results showed the effects of the different irrigation levels and seasons on the vegetative growth and fruit yield characteristics. The cumulative trunk diameter, the annual shoot growth, the number of fruits per tree, and the yield decreased from the full water restitution (100% ETc) to the severe water restriction (25% ETc). The weight and the size of fruits decreased significantly with the restriction of water volumes applied to the crop. A linear relationship between water consumption and yield (R = 1.00 in 2018 and 1.21 in 2019; n = 12) was found. The water use efficiency (WUE) gave no statistical differences among irrigation treatments. The yield response factors (Ky: 1.06 in 2018 and 0.99 in 2019) showed the sensitivity of pomegranates to water deficits. Full article

(This article belongs to the Section Fruit Production Systems)

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29 pages, 2847 KiB

Open AccessEditor’s ChoiceReview

Genetic Engineering of Eggplant (Solanum melongena L.): Progress, Controversy and Potential

by Iftekhar Alam and Md Salimullah

Horticulturae 2021, 7(4), 78; https://doi.org/10.3390/horticulturae7040078 - 11 Apr 2021

Cited by 40 | Viewed by 28624

Abstract

Eggplant (Solanum melongena) is the third most important vegetable in Asia and of considerable importance in the Mediterranean belt. Although global eggplant production has been increasing in recent years, productivity is limited due to insects, diseases, and abiotic stresses. Genetic engineering [...] Read more.

Eggplant (Solanum melongena) is the third most important vegetable in Asia and of considerable importance in the Mediterranean belt. Although global eggplant production has been increasing in recent years, productivity is limited due to insects, diseases, and abiotic stresses. Genetic engineering offers new traits to eggplant, such as seedless parthenocarpic fruits, varieties adapted to extreme climatic events (i.e., sub- or supra-optimal temperatures), transcription factor regulation, overexpressing osmolytes, antimicrobial peptides, Bacillusthuringiensis (Bt) endotoxins, etc. Such traits either do not occur naturally in eggplant or are difficult to incorporate by conventional breeding. With controversies, Bt-expressing eggplant varieties resistant to eggplant fruit and shoot borers have already been adopted for commercial cultivation in Bangladesh. However, to maximize the benefits of transgenic technology, future studies should emphasize testing transgenic plants under conditions that mimic field conditions and focus on the plant’s reproductive stage. In addition, the availability of the whole genome sequence, along with an efficient in vitro regeneration system and suitable morphological features, would make the eggplant an alternative model plant in which to study different aspects of plant biology in the near future. Full article

(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))

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16 pages, 1883 KiB

Open AccessEditor’s ChoiceArticle

Nutrient Concentration of African Horned Cucumber (Cucumis metuliferus L) Fruit under Different Soil Types, Environments, and Varying Irrigation Water Levels

by Mdungazi K Maluleke, Shadung J Moja, Melvin Nyathi and David M Modise

Horticulturae 2021, 7(4), 76; https://doi.org/10.3390/horticulturae7040076 - 10 Apr 2021

Cited by 16 | Viewed by 4284

Abstract

The nutrient concentration of most crops depends on factors such as amount of water, growing environment, sunlight, and soil types. However, the factors influencing nutrient concentration of African horned cucumber fruit are not yet known. The objective of the study was to determine [...] Read more.

The nutrient concentration of most crops depends on factors such as amount of water, growing environment, sunlight, and soil types. However, the factors influencing nutrient concentration of African horned cucumber fruit are not yet known. The objective of the study was to determine the effect of different water stress levels, soil types, and growing environments on the nutrient concentration of African horned cucumber fruit. Freeze-dried fruit samples were used in the quantification of β-carotene and total soluble sugars. The results demonstrated that plants grown under the shade net, combined with severe water stress level and loamy soil, had increased total soluble sugars (from 8 to 16 °Brix). Under the shade-net environment, the combination of moderate water stress level and loamy soil resulted in increased crude protein content (from 6.22 to 6.34% °Brix). In addition, the severe water stress treatment combined with loamy soil, under greenhouse conditions, resulted in increased β-carotene content (from 1.5 to 1.7 mg 100 g⁻¹ DW). The results showed that African horned cucumber fruits are nutrient-dense when grown under moderate water stress treatment on the loamy or sandy loam substrate in the shade-net and open-field environments. Full article

(This article belongs to the Special Issue Horticultural Crop Response to Different Environmental and Nutritional Stress)

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8 pages, 1028 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Multiple Amino Acids Inhibit Postharvest Senescence of Broccoli

by Muhammad Sohail, Ron Baden Howe Wills, Michael C. Bowyer and Penta Pristijono

Horticulturae 2021, 7(4), 71; https://doi.org/10.3390/horticulturae7040071 - 4 Apr 2021

Cited by 19 | Viewed by 4200

Abstract

The function of free amino acids in protein synthesis, as a source of energy and unique roles in catabolism have been well studied in plant development but their function in postharvest fruit and vegetables has received little attention. This study evaluated 11 amino [...] Read more.

The function of free amino acids in protein synthesis, as a source of energy and unique roles in catabolism have been well studied in plant development but their function in postharvest fruit and vegetables has received little attention. This study evaluated 11 amino acids—arginine, alanine, aspartic acid, glutamic acid, glycine, ornithine, phenylalanine, serine, tyrosine, tryptophan and valine—on the development of senescence of broccoli. Broccoli florets were dipped in 5 mM solution of amino acids, then stored at 10 °C in air containing 0.1 µL L⁻¹ ethylene. Senescence was assessed by green life, ethylene production, respiration rate and ion leakage. Green life was increased by all the amino acids except valine. Similarly, ethylene production and ion leakage were decreased by all the amino acids except valine, while respiration rate was reduced by all amino acids. It is speculated that the early reduction in ethylene production could be the mechanism by which the amino acids delayed senescence. The beneficial effect of naturally occurring amino acids in inhibiting senescence has potential commercial relevance, as the amino acids have Generally Recognised As Safe (GRAS) status which should assist gain regulatory approval, and gain acceptance by consumers wary of synthetic chemicals on foods. Full article

(This article belongs to the Special Issue Advances in Improving Fresh Produce Quality and Postharvest Shelf Life)

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14 pages, 4496 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Analysis and Expression Tendency of Banana (Musa acuminata L.) Calcineurin B-Like (MaCBL) Genes under Potassium Stress

by Ying Xiong, Ruimei Li, Xuejun Lin, Yangjiao Zhou, Fenlian Tang, Yuan Yao, Jiao Liu, Lixia Wang, Xiaomin Yin, Yongxia Liu, Jianchun Guo, Yan Zhao and Yingdui He

Horticulturae 2021, 7(4), 70; https://doi.org/10.3390/horticulturae7040070 - 3 Apr 2021

Cited by 6 | Viewed by 3492

Abstract

Calcineurin B-like (CBL) proteins are reported to play significant roles in plant development and ion-transport regulation. Potassium shortages are a serious problem in banana cultivation. However, to date, the members of the banana CBL gene family, and their function in regulating potassium stress, [...] Read more.

Calcineurin B-like (CBL) proteins are reported to play significant roles in plant development and ion-transport regulation. Potassium shortages are a serious problem in banana cultivation. However, to date, the members of the banana CBL gene family, and their function in regulating potassium stress, remain unclear. In this study, 11 CBL genes were identified from the banana genome and grouped into four groups (Group I–IV) based on their phylogenetic relationships. The genomic features of these MaCBL genes were analyzed, focusing on their gene structures, standpat motifs, chromosomal distributions, and evolutionary history. Expression pattern analysis revealed that the MaCBLs were function-specific. Further qRT-PCR analysis indicated that the presence of MaCBL2 was indeed a response to potassium deficiency stress. The MaCBL2 gene was cloned, and sequence alignment indicated that it contained four elongation factor hand (EF-hand) domains, the conserved N-terminal myristoylation domain “MGCXXS/K(T)” and the “FPSF” motif. Subcellular location analysis showed that MaCBL2 was located in the plasma membrane, nucleus and cytoplasm. The overexpression of MaCBL2 could restore the growth of the yeast mutant R5421 on a K⁺-deficient medium. The overexpression of MaCBL2 could promote the root length of transgenic seedlings on K⁺-deficient medium. These findings indicate that MaCBL2 was, in our study, the key gene of the CBL family in responding to potassium deficiency in bananas. Our discoveries have established a considerable basis for the further study and application of MaCBL genes. Full article

(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))

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22 pages, 15887 KiB

Open AccessEditor’s ChoiceReview

Edible Flowers: Antioxidant Compounds and Their Functional Properties

by Nadhila B. Prabawati, Viki Oktavirina, Miguel Palma and Widiastuti Setyaningsih

Horticulturae 2021, 7(4), 66; https://doi.org/10.3390/horticulturae7040066 - 1 Apr 2021

Cited by 41 | Viewed by 10865

Abstract

Edible flowers have been widely consumed for ages until now. The attractive colors and shapes, exotic aroma, and delightful taste make edible flowers very easy to attain. Moreover, they also provide health benefits for consumers due to the unique composition and concentration of [...] Read more.

Edible flowers have been widely consumed for ages until now. The attractive colors and shapes, exotic aroma, and delightful taste make edible flowers very easy to attain. Moreover, they also provide health benefits for consumers due to the unique composition and concentration of antioxidant compounds in the matrices. Knowing the bioactive compounds and their functional properties from edible flowers is necessary to diversify the usage and reach broader consumers. Therefore, this reported review could be useful for functional product development, engaging the discussed edible flowers. We present a comprehensive review of edible flower composition and the functional properties of their antioxidant compounds, mainly phenolics. Full article

(This article belongs to the Special Issue Biodiversity, Production, Processing and Quality along the Chain of Herbal and Edible Flowers)

13 pages, 1643 KiB

Open AccessEditor’s ChoiceArticle

The Use of Halophytic Companion Plant (Portulaca oleracea L.) on Some Growth, Fruit, and Biochemical Parameters of Strawberry Plants under Salt Stress

by Sema Karakas, Ibrahim Bolat and Murat Dikilitas

Horticulturae 2021, 7(4), 63; https://doi.org/10.3390/horticulturae7040063 - 26 Mar 2021

Cited by 20 | Viewed by 4777

Abstract

Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L⁻¹) conditions with or without a halophytic companion plant ( [...] Read more.

Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L⁻¹) conditions with or without a halophytic companion plant (Portulaca oleracea L.) were elucidated in a pot experiment. Salt stress negatively affected the growth, physiological (stomatal conductance and electrolyte leakage), and biochemical parameters such as chlorophyll contents (chl-a and chl-b); proline, hydrogen peroxide, malondialdehyde, catalase, and peroxidase enzyme activities; total soluble solids; and lycopene and vitamin C contents, as well as the mineral uptake, of strawberry plants. The companionship of P. oleracea increased fresh weight, dry weight, and fruit average weight, as well as the total fruit yield of strawberry plants along with improvements of physiological and biochemical parameters. This study showed that the cultivation of P. oleracea with strawberry plants under salt stress conditions effectively increased strawberry fruit yield and quality. Therefore, we suggest that approaches towards the use of P. oleracea could be an environmentally friendly method that should be commonly practiced where salinity is of great concern. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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15 pages, 2722 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimization of Substrate and Nutrient Solution Strength for Lettuce and Chinese Cabbage Seedling Production in the Semi-Arid Environment of Central Myanmar

by Nicola Michelon, Giuseppina Pennisi, Nang Ohn Myint, Francesco Orsini and Giorgio Gianquinto

Horticulturae 2021, 7(4), 64; https://doi.org/10.3390/horticulturae7040064 - 26 Mar 2021

Cited by 7 | Viewed by 5063

Abstract

The growing population of tropical countries has led to a new awareness of the importance of vegetables as a source of essential foods and nutrients. The success of vegetable cultivation depends to a large extent on high-quality seedlings. This work aimed at evaluating [...] Read more.

The growing population of tropical countries has led to a new awareness of the importance of vegetables as a source of essential foods and nutrients. The success of vegetable cultivation depends to a large extent on high-quality seedlings. This work aimed at evaluating the effects of different substrates and different nutrient solution concentrations on the development of lettuce and Chinese cabbage seedlings in a semi-arid tropical area. Three independent experiments were conducted at the Soil and Water Research Station at Yezin Agriculture University, Myanmar (Myanmar, 19.83° N; 96.27° E). In all experiments a randomized block design was implemented with four treatments and three repetitions. In the first experiment the adaptability of lettuce seedling to two substrates (namely a Hulls Manure mix composed by 50% of mature cattle manure and 50% of carbonized rice husk and a soil based substrate constituted by 70% local soil, 20% burned rice husk, and 10% fresh cattle manure) and two nutrient solutions with different electrical conductivities (ECs) (W_0.1, stored rainwater with EC = 0.13 dS m⁻¹ and NS_1.2, nutrient solution with EC = 1.20 dS m⁻¹) were tested. In the second and third experiments, two species (lettuce and Chinese cabbage) were assessed for their response to nutrient solution concentrations. In both crops, 4 fertigation treatments (W_0.1; NS_0.6; NS_1.2; and NS_1.8) were supplied, by modulating the concentration of a compound mineral fertilizer (15:15:15) in the following ranges: W_0.1: 0 g L⁻¹, electrical conductivity (EC) 0.13 dS m⁻¹, NS_0.6: 0.3 g L⁻¹, EC of 0.60 dS m⁻¹; NS_1.2: 0.6 g L⁻¹, 1.2 dS m⁻¹ EC, and NS_1.8: 0.9 g L⁻¹, 1.8 dS m⁻¹ EC. Adopting different substrates and applying different nutrient solutions significantly affected growth (fresh weight and leaf morphology) and some physiological parameters (stomatal conductance, leaf temperature, and leaf chlorophyll content) of lettuce and Chinese cabbage seedling. From the first experiment, the combination of the soil based substrate and NS_1.2 treatments allowed us to improve the seedlings’ growth. In the second experiment, highest growth of lettuce and Chinese cabbage seedlings was associated with NS_1.2 and NS_1.8, respectively. The presented results allow for the optimization of both growing media and nutrient solution management when lettuce and Chinese cabbage seedling are produced in the Central Dry Zone of Myanmar. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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11 pages, 3011 KiB

Open AccessEditor’s ChoiceArticle

Effect of Root Restriction on the Performance of Three-Truss Cultivated Tomato in the Low-Node Pinching Order at High-Density Cultivation System

by Alex Williams Ayarna, Satoru Tsukagoshi and George Oduro Nkansah

Horticulturae 2021, 7(3), 60; https://doi.org/10.3390/horticulturae7030060 - 22 Mar 2021

Cited by 9 | Viewed by 3390

Abstract

The low-node pinching order at a high-density plant cultivation system (LN&HD) is now widely adopted for increasing tomato yield and fruit quality. The LN&HD cultivation period spans 70–120 days, employs the use of a small amount of substrate (low substrate volume), and plants [...] Read more.

The low-node pinching order at a high-density plant cultivation system (LN&HD) is now widely adopted for increasing tomato yield and fruit quality. The LN&HD cultivation period spans 70–120 days, employs the use of a small amount of substrate (low substrate volume), and plants are usually topped between the first and the fourth truss. Using a small amount of substrate in cultivation induces root restriction. Increasing the extent of root restriction in small pots has been adopted for increasing the fruit quality of tomato in some advanced countries. However, improving fruit quality at the expense of yield becomes a major drawback for adopting the LN&HD in Ghana. The LN&HD was introduced into Ghana mainly to increase tomato yield sustainably at a cost-effective level. This study aimed to manipulate or reduce the extent of root restriction to increase tomato yield. Information related to manipulating or reducing the extent of root restriction has not been extensively reported. Thus, an experiment was conducted (between 21 April 2019 and 11 August 2019) in the greenhouse of the University of Ghana Forest and Horticultural Research Centre, Kade-Ghana. Plants of two tomato cultivars (Jaguar and Momotaro York) were subjected to four root restriction conditions. The extent of root restriction were (1) complete root restriction in a 1.0 L volume capacity pot, (2) complete root restriction in a 1.5 L volume capacity pot, (3) partial root restriction in Rockwool-like cultivation, otherwise referred to as Cocowool, and (4) No root restriction in a trough containing 1.5 L of the substrate. The experiment was laid out in a 2 x 4 factorial in a randomized complete block. Results showed that partial root restriction in Cocowool and unrestricted roots in the trough produced the highest tomato yield and total dry matter compared to the plants that received complete root restrictions in the 1.0 and 1.5 L pots. However, the tomato’s total soluble solids increased with a complete root restriction in the 1.0 L pot. Reducing the extent of root restriction increased the yield and total dry matter of tomato. With the LN&HD, a small amount of substrate could be used (at a reduced cost) with a partial root restriction to increase the yield of tropical tomato cultivars grown in Ghana. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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17 pages, 3271 KiB

Open AccessEditor’s ChoiceArticle

Estimation of Glucosinolates and Anthocyanins in Kale Leaves Grown in a Plant Factory Using Spectral Reflectance

by Milon Chowdhury, Viet-Duc Ngo, Md Nafiul Islam, Mohammod Ali, Sumaiya Islam, Kamal Rasool, Sang-Un Park and Sun-Ok Chung

Horticulturae 2021, 7(3), 56; https://doi.org/10.3390/horticulturae7030056 - 21 Mar 2021

Cited by 14 | Viewed by 5258

Abstract

The spectral reflectance technique for the quantification of the functional components was applied in different studies for different crops, but related research on kale leaves is limited. This study was conducted to estimate the glucosinolate and anthocyanin components of kale leaves cultivated in [...] Read more.

The spectral reflectance technique for the quantification of the functional components was applied in different studies for different crops, but related research on kale leaves is limited. This study was conducted to estimate the glucosinolate and anthocyanin components of kale leaves cultivated in a plant factory based on diffuse reflectance spectroscopy through regression methods. Kale was grown in a plant factory under different treatments. After specific periods of transplantation, leaf samples were collected, and reflectance spectra were measured immediately from nine different points on each leaf. The same leaf samples were freeze-dried and stored for analysis of the functional components. Regression procedures, such as principal component regression (PCR), partial least squares regression (PLSR), and stepwise multiple linear regression (SMLR), were applied to relate the functional components with the spectral data. In the laboratory analysis, progoitrin and glucobrassicin, as well as cyanidin and malvidin, were found to be dominating components in glucosinolates and anthocyanins, respectively. From the overall analysis, the SMLR model showed better performance, and the identified wavelengths for estimating the glucosinolates and anthocyanins were in the early near-infrared (NIR) region. Specifically, reflectance at 742, 761, 787, 796, 805, 833, 855, 932, 947, and 1000 nm showed a strong correlation. Full article

(This article belongs to the Special Issue Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Green, Red and Flowering Plants)

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9 pages, 1256 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Astilbe and Coneflower Growth as Affected by Fertilizer Rate and Substrate Volumetric Water Content

by Amanda Bayer

Horticulturae 2021, 7(3), 52; https://doi.org/10.3390/horticulturae7030052 - 16 Mar 2021

Cited by 2 | Viewed by 2759

Abstract

Improved irrigation and fertilization practices, such as reduced applications, are needed to improve the sustainability of container plant production. The objective of this study was to assess growth of Visions astilbe (Astilbe chinensis ‘Visions’) and Mellow Yellow coneflower (Echinacea purpurea ‘Mellow [...] Read more.

Improved irrigation and fertilization practices, such as reduced applications, are needed to improve the sustainability of container plant production. The objective of this study was to assess growth of Visions astilbe (Astilbe chinensis ‘Visions’) and Mellow Yellow coneflower (Echinacea purpurea ‘Mellow Yellow’) grown at two controlled-release fertilizer (CRF) rates (100% or 50% of the medium bag rate) and two volumetric water contents (VWC; 40% and 18%). For coneflower, there were no significant treatment effects for height, growth index, shoot dry weight, or leaf size. There was a significant VWC effect on number of flowers with the 40% treatment having more flowers (5.6) per plant than the 18% treatment (2.7). Shoot dry weight, growth index, and leaf size of astilbe were greater for the 40% VWC treatment than the 18% VWC treatment with no fertilizer rate effect. Astilbe height and number of flowers was not significant. These results indicate that there is a species-specific effect of VWC on growth whereas reduced fertilizer applications are possible for both species without impacting growth. Although a substrate VWC of 18% is likely too low to produce salable plants, a VWC below 40% can potentially be used to support adequate growth. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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10 pages, 260 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Overview of the Dynamic Role of Specialty Cut Flowers in the International Cut Flower Market

by Anastasios Darras

Horticulturae 2021, 7(3), 51; https://doi.org/10.3390/horticulturae7030051 - 14 Mar 2021

Cited by 62 | Viewed by 13490

Abstract

The global cut flower industry has faced serious challenges over the years, but still remains an important sector of agriculture. Floriculture businesses seek new, innovative trends and niches to help increase product sales. Specialty cut flower (SCF) production has increased in the past [...] Read more.

The global cut flower industry has faced serious challenges over the years, but still remains an important sector of agriculture. Floriculture businesses seek new, innovative trends and niches to help increase product sales. Specialty cut flower (SCF) production has increased in the past 20 years in the US, Australia, Africa, and Europe. SCF production and sales could increase further if these new products were supported by dynamic marketing campaigns that focus on their strengths compared to the traditional cut flowers (TCF) such as roses, carnations, gerberas, and chrysanthemums. The major strength of SCF is the eco-friendly profile, which is associated to low CO₂ footprints and environmental outputs. This contrasts TCF cultivation, which is associated to high energy inputs, especially at the traditional production centres (e.g., The Netherlands). It is suggested that environmental legislations, production costs, and customer demand for eco-friendly products will positively affect future SCF cultivation and sale. Full article

(This article belongs to the Special Issue Trends in Ornamental Plant Production)

36 pages, 865 KiB

Open AccessEditor’s ChoiceReview

Response Mechanism of Plants to Drought Stress

by Xinyi Yang, Meiqi Lu, Yufei Wang, Yiran Wang, Zhijie Liu and Su Chen

Horticulturae 2021, 7(3), 50; https://doi.org/10.3390/horticulturae7030050 - 13 Mar 2021

Cited by 641 | Viewed by 71073

Abstract

With the global climate anomalies and the destruction of ecological balance, the water shortage has become a serious ecological problem facing all mankind, and drought has become a key factor restricting the development of agricultural production. Therefore, it is essential to study the [...] Read more.

With the global climate anomalies and the destruction of ecological balance, the water shortage has become a serious ecological problem facing all mankind, and drought has become a key factor restricting the development of agricultural production. Therefore, it is essential to study the drought tolerance of crops. Based on previous studies, we reviewed the effects of drought stress on plant morphology and physiology, including the changes of external morphology and internal structure of root, stem, and leaf, the effects of drought stress on osmotic regulation substances, drought-induced proteins, and active oxygen metabolism of plants. In this paper, the main drought stress signals and signal transduction pathways in plants are described, and the functional genes and regulatory genes related to drought stress are listed, respectively. We summarize the above aspects to provide valuable background knowledge and theoretical basis for future agriculture, forestry breeding, and cultivation. Full article

(This article belongs to the Special Issue Drought Stress in Horticultural Plants)

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11 pages, 3054 KiB

Open AccessEditor’s ChoiceArticle

Bacillus licheniformis PR2 Controls Fungal Diseases and Increases Production of Jujube Fruit under Field Conditions

by Jun-Hyeok Kwon, Sang-Jae Won, Jae-Hyun Moon, Uk Lee, Yun-Serk Park, Chaw Ei Htwe Maung, Henry B. Ajuna and Young Sang Ahn

Horticulturae 2021, 7(3), 49; https://doi.org/10.3390/horticulturae7030049 - 12 Mar 2021

Cited by 27 | Viewed by 5578

Abstract

There is a growing interest in using biocontrol agents to control fungal diseases and increase the production of jujube fruit (Zizyphus jujua Miller var. inermis Rehder). The purpose of this study was to use Bacillus licheniformis PR2 to inhibit fungal diseases and [...] Read more.

There is a growing interest in using biocontrol agents to control fungal diseases and increase the production of jujube fruit (Zizyphus jujua Miller var. inermis Rehder). The purpose of this study was to use Bacillus licheniformis PR2 to inhibit fungal diseases and promote fruit production in jujube orchards. B. licheniformis PR2 secreted 92.4 unit/mL of chitinase, which inhibited fungal phytopathogens through hyphal alterations with swelling and bulbous structures. B. licheniformis PR2 also inhibited mycelial growths of fruit fungal pathogens Botrytis cinerea, Colletotrichum gloeosporioides, and Phytophthora nicotianae by 81.3%, 60.1%, and 67.0%, respectively. B. licheniformis PR2 increased jujube fruit yield by 17.9 kg/tree by reducing rotting damage caused by fungal pathogens, with a yield 3.2 times higher than that achieved by the control without PR2 treatment. In addition, B. licheniformis PR2 produced auxin, which promoted cell division after flower fertilization, thus increasing fruit length and diameter by 1.2-fold compared to those of the control. These results confirmed that eco-friendly B. licheniformis PR2 could effectively control fungal diseases in jujube orchards and improve its fruit size and yield. Full article

(This article belongs to the Special Issue The Effect of Plant Pathogens on Horticultural Plants)

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14 pages, 622 KiB

Open AccessEditor’s ChoiceArticle

Opportunities of Reduced Nitrogen Supply for Productivity, Taste, Valuable Compounds and Storage Life of Cocktail Tomato

by Lilian Schmidt and Jana Zinkernagel

Horticulturae 2021, 7(3), 48; https://doi.org/10.3390/horticulturae7030048 - 11 Mar 2021

Cited by 5 | Viewed by 3188

Abstract

Vegetable production requires high nutrient input for ensuring high quality and high yield. As this is ecologically disadvantageous, it is necessary to determine if nitrogen (N) fertilization can be reduced without negative effects on productivity. For quality reasons, the effects of reduced N [...] Read more.

Vegetable production requires high nutrient input for ensuring high quality and high yield. As this is ecologically disadvantageous, it is necessary to determine if nitrogen (N) fertilization can be reduced without negative effects on productivity. For quality reasons, the effects of reduced N supply on taste, valuable compounds and storage life must be elucidated in parallel. This study examines whether reducing the N supply of cocktail tomatoes by 50% to recommendations affects the yield and quality of tomato fruits. Three varieties with different skin colors, yellow-orange (‘Apresa’), red (‘Delioso’) and brown (‘Bombonera’), were grown in soil in a greenhouse and harvested at the red-ripen stage. Quality parameters were assessed at harvest and after eight-day storage. Total yield decreased exclusively with ‘Bombonera’ due to reduced fruit weight. Firmness of the fruit pulp, concentrations of minerals, soluble solid contents, total acidity, total phenolics and liposoluble pigments of fruits were not influenced. However, storage affected chemical compositions positively, as shown by increased antioxidants. Descriptive sensory analyses revealed no impact of reduced N supply. From the perspective of the yield, quality and shelf life of fruits, reducing the N supply by 50% offers opportunities for the three cocktail tomato varieties in soil cultivation. Full article

(This article belongs to the Special Issue Managing the Product Quality of Vegetable Crops under Abiotic Stress)

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16 pages, 1007 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Assessment of Chilling Requirement and Threshold Temperature of a Low Chill Pear (Pyrus communis L.) Germplasm in the Mediterranean Area

by Filippo Ferlito, Mario Di Guardo, Maria Allegra, Elisabetta Nicolosi, Alberto Continella, Stefano La Malfa, Alessandra Gentile and Gaetano Distefano

Horticulturae 2021, 7(3), 45; https://doi.org/10.3390/horticulturae7030045 - 6 Mar 2021

Cited by 11 | Viewed by 3795

Abstract

In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species are regulated by precise chilling and heating requirements. To investigate this aspect, sixty-one accessions of European pear (Pyrus communis L.) collected in Sicily were phenotyped for three [...] Read more.

In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species are regulated by precise chilling and heating requirements. To investigate this aspect, sixty-one accessions of European pear (Pyrus communis L.) collected in Sicily were phenotyped for three consecutive years for harvest date, bud sprouting and blooming to determine both the chilling requirements and the threshold temperature using the Chill Days model. The whole germplasm collection was grown in two different experimental fields located at 10 and 850 m above sea level representing two Mediterranean-type climates in which pear is commonly cultivated. Results revealed a mean threshold temperature of 6.70 and 8.10 °C for the two experimental fields, respectively, with a mean chilling requirement ranging from −103 and −120 days. Through this approach, novel insights were gained on the differences in chilling requirement for early flowering cultivars to overcome dormancy. Furthermore, to better dissect differences in chilling requirement between accessions, the sprouting bud rate of six cultivars was assessed on excised twigs stored at 4 ± 0.1 °C from 300 to 900 h followed by a period at 25 ± 0.1 °C varying from seven to twenty-eight days. Results of both experiments highlighted that Sicilian pear germplasm is characterized by a low chilling requirement compared to other pear germplasm, making Sicilian local accessions valuable candidates to be used for selecting novel cultivars, coupling their low chilling requirements with other traits of agronomical interest. Full article

(This article belongs to the Section Fruit Production Systems)

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10 pages, 2088 KiB

Open AccessEditor’s ChoiceArticle

Growth and Competitive Infection Behaviors of Bradyrhizobium japonicum and Bradyrhizobium elkanii at Different Temperatures

by Md Hafizur Rahman Hafiz, Ahsanul Salehin and Kazuhito Itoh

Horticulturae 2021, 7(3), 41; https://doi.org/10.3390/horticulturae7030041 - 28 Feb 2021

Cited by 7 | Viewed by 4860

Abstract

Growth and competitive infection behaviors of two sets of Bradyrhizobium spp. strains were examined at different temperatures to explain strain-specific soybean nodulation under local climate conditions. Each set consisted of three strains—B. japonicum Hh 16-9 (Bj11-1), B. japonicum Hh 16-25 (Bj11-2), and [...] Read more.

Growth and competitive infection behaviors of two sets of Bradyrhizobium spp. strains were examined at different temperatures to explain strain-specific soybean nodulation under local climate conditions. Each set consisted of three strains—B. japonicum Hh 16-9 (Bj11-1), B. japonicum Hh 16-25 (Bj11-2), and B. elkanii Hk 16-7 (BeL7); and B. japonicum Kh 16-43 (Bj10J-2), B. japonicum Kh 16-64 (Bj10J-4), and B. elkanii Kh 16-7 (BeL7)—which were isolated from the soybean nodules cultivated in Fukagawa and Miyazaki soils, respectively. The growth of each strain was evaluated in Yeast Mannitol (YM) liquid medium at 15, 20, 25, 30, and 35 °C with shaking at 125 rpm for one week while measuring their OD₆₆₀ daily. In the competitive infection experiment, each set of the strains was inoculated in sterilized vermiculite followed by sowing surface-sterilized soybean seeds, and they were cultivated at 20/18 °C and 30/28 °C in a 16/8 h (day/night) cycle in a phytotron for three weeks, then nodule compositions were determined based on the partial 16S-23R rRNA internal transcribes spacer (ITS) gene sequence of DNA extracted from the nodules. The optimum growth temperatures were at 15–20 °C for all B. japonicum strains, while they were at 25–35 °C for all B. elkanii strains. In the competitive experiment with the Fukagawa strains, Bj11-1 and BeL7 dominated in the nodules at the low and high temperatures, respectively. In the Miyazaki strains, BjS10J-2 and BeL7 dominated at the low and high temperatures, respectively. It can be assumed that temperature of soil affects rhizobia growth in rhizospheres and could be a reason for the different competitive properties of B. japonicum and B. elkanii strains at different temperatures. In addition, competitive infection was suggested between the B. japonicum strains. Full article

(This article belongs to the Special Issue Horticultural Crop Response to Different Environmental and Nutritional Stress)

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14 pages, 2284 KiB

Open AccessEditor’s ChoiceArticle

Changes in the Metabolite Profile during Micropropagation of Normal and Somaclonal Variants of Banana Musa AAA cv. Williams

by Fredy P. Carrera, Carlos Noceda, María G. Maridueña-Zavala, José A. García, Omar Ruiz-Barzola and Juan M. Cevallos-Cevallos

Horticulturae 2021, 7(3), 39; https://doi.org/10.3390/horticulturae7030039 - 26 Feb 2021

Cited by 4 | Viewed by 4579

Abstract

Micropropagation techniques allow the mass production of banana plants but can cause somaclonal variations such as dwarfism. Changes in the metabolite profile during micropropagation of normal (NP) and dwarf (DP) banana plants have not been described. Both, NPs and DPs of banana Musa [...] Read more.

Micropropagation techniques allow the mass production of banana plants but can cause somaclonal variations such as dwarfism. Changes in the metabolite profile during micropropagation of normal (NP) and dwarf (DP) banana plants have not been described. Both, NPs and DPs of banana Musa AAA cv. Williams were micropropagated and the metabolite profile of vitroplants was assessed at the proliferation (PP), rooting (RP) and the second greenhouse-acclimatization (APII) phases of tissue culture. Metabolites from 10 DPs and 10 NPs meristems from each micropropagation phase were extracted and identified by gas chromatography coupled with mass spectrometry (GC-MS). Principal component analysis (PCA) and test of statistical significance were applied to detect differentially accumulated metabolites. The PCA showed a clear grouping of DPs separated from NPs in RP and APII. Among the differentially accumulated metabolites, various precursors of apoplast components including arabinose and galactose or deoxygalactose in both PP and RP, as well as mannose and fucose in APII were under-accumulated in DPs. Results suggest affected apoplast composition during micropropagation of DPs. Full article

(This article belongs to the Section Propagation and Seeds)

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13 pages, 958 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Higher Temperatures Decrease Fruit Size in Strawberry Growing in the Subtropics

by Christopher Menzel

Horticulturae 2021, 7(2), 34; https://doi.org/10.3390/horticulturae7020034 - 23 Feb 2021

Cited by 27 | Viewed by 5738

Abstract

Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than [...] Read more.

Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than 12 g until 28 October. Additional data were collected on fruit soluble solids content (SSC) and titratable acidity (TA) from 16 September to 28 October. Minimum temperatures were 2 °C to 4 °C higher than the long-term averages from 1965 to 1990. Changes in marketable yield followed a dose-logistic pattern (p < 0.001, R²s = 0.99). There was a strong negative relationship between fruit weight (marketable) and the average daily mean temperature in the four or seven weeks before harvest from 29 July to 28 October (p < 0.001, R²s = 0.90). There were no significant relationships between SSC and TA, and temperatures in the eight days before harvest from 16 September to 28 October (p > 0.05). The plants continued to produce a marketable crop towards the end of the season, but the fruit were small and more expensive to harvest. Higher temperatures in the future are likely to affect the economics of strawberry production in subtropical locations. Full article

(This article belongs to the Section Fruit Production Systems)

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41 pages, 1590 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Methodologies in the Analysis of Phenolic Compounds in Roselle (Hibiscus sabdariffa L.): Composition, Biological Activity, and Beneficial Effects on Human Health

by Bety W. Hapsari, Manikharda and Widiastuti Setyaningsih

Horticulturae 2021, 7(2), 35; https://doi.org/10.3390/horticulturae7020035 - 23 Feb 2021

Cited by 49 | Viewed by 13085

Abstract

Roselle (Hibiscus sabdariffa L.), as an edible flower, has long provided an array of positive effects on human health. This benefit is a result of phenolic compounds that are naturally present mainly in the calyx. Plentiful medicinal remedies and functional foods based [...] Read more.

Roselle (Hibiscus sabdariffa L.), as an edible flower, has long provided an array of positive effects on human health. This benefit is a result of phenolic compounds that are naturally present mainly in the calyx. Plentiful medicinal remedies and functional foods based on this flower are available worldwide, as supported by the studies of phenolic compounds in recent decades. This paper aims to provide a comprehensive review of the composition, biological activity, and beneficial effects on human health of phenolic compounds in roselle. This review was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A structured search in the published literature for phenolics compositions in roselle was required prior to the evaluation on the validity of the reported analytical methods. Reliable identification and quantification of phenolic compounds in roselle can be achieved by employing the proper extraction and separation methods. With ample alternative analytical methods discussed here, this review provided an aid for comprehending and selecting the most appropriate method for a particular study. The applications of the analytical methods highlighted indicated that phenolic acids, flavonoids, and their derivatives have been identified and quantified in roselle with a range of biological activities and beneficial effects on human health. It was also disclosed that the composition and concentration of phenolic compounds in roselle vary due to the growth factors, cultivars, and environmental influence. Finally, apart from the research progress carried out with roselle during the last ten years, this review also proposed relevant future works. Full article

(This article belongs to the Special Issue Biodiversity, Production, Processing and Quality along the Chain of Herbal and Edible Flowers)

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22 pages, 7654 KiB

Open AccessEditor’s ChoiceArticle

Evaluating the Drought Endurance of Landscaping Ground Cover Plants in a Roof Top Model

by Nath Pichakum and Aussanee Pichakum

Horticulturae 2021, 7(2), 31; https://doi.org/10.3390/horticulturae7020031 - 13 Feb 2021

Cited by 3 | Viewed by 4029

Abstract

Vegetative ground covers are commonly used in urban, tropical roadside gardens. Such landscaping ground covers usually encounter extreme water-deficits and high temperatures from vehicles and urban infrastructures. However, information about the plant species that are appropriate for low maintenance gardens is not available, [...] Read more.

Vegetative ground covers are commonly used in urban, tropical roadside gardens. Such landscaping ground covers usually encounter extreme water-deficits and high temperatures from vehicles and urban infrastructures. However, information about the plant species that are appropriate for low maintenance gardens is not available, especially in tropical areas. This study aimed to investigate potential indicators for evaluating plant tolerance to water-deficit situations. A non-irrigated rooftop model was used to test 25 commercial ground cover species in a greenhouse at Mahidol University, Nakhon Pathom Province, Thailand. Each of these 25 species was potted and subjected to one of two conditions: with or without irrigation for 7 days. Physiological responses relevant to plant endurance during water-deficits were monitored, including changes in leaf relative water content (RWC), percent stomatal opening, leaf surface temperature, leaf total chlorophyll content, leaf greenness, maximum quantum yield, and light quantum yield. Moreover, an additional indicator of landscape utility was evaluated, where each species was judged by trained panelists for their esthetic appeal. Diverse responses were observed based on the type of physiological parameter measured, plant species, and duration of drought conditions. Water withdrawal for three days was deemed an appropriate time to determine plant tolerance to water-deficit conditions, as signs of stress were clearly observed in three parameters, i.e., changes in leaf RWC, percent stomatal opening, and esthetic score. Lastly, cluster analysis revealed that seven plant species were appropriate for tropical, urban ground covers, as they had high endurance under water-deficit conditions, namely, Allium schoenoprasum,Liriope muscari, Aloe sp., Sedum x rubrotinctum, Alternanthera ficoidea, Pilea libanensis and Plectranthus scutellarioides. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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15 pages, 1173 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Fertigation Management on the Quality of Organic Legumes Grown in Protected Cultivation

by María del Carmen García-García, Rafael Font, Pedro Gómez, Juan Luis Valenzuela, Juan A. Fernández and Mercedes Del Río-Celestino

Horticulturae 2021, 7(2), 28; https://doi.org/10.3390/horticulturae7020028 - 7 Feb 2021

Cited by 6 | Viewed by 3446

Abstract

Appropriate fertigation management plays an important role in increasing crop quality and economizing water. The objective of the study was to determine the effects of two fertigation treatments, normal (T100) and 50% sustained deficit (T50), on the physico-chemical quality of legumes. The determinations [...] Read more.

Appropriate fertigation management plays an important role in increasing crop quality and economizing water. The objective of the study was to determine the effects of two fertigation treatments, normal (T100) and 50% sustained deficit (T50), on the physico-chemical quality of legumes. The determinations were performed on the edible parts of peas, French beans and mangetout. The trials were conducted in a protected cultivation certified organic farm. The response of legumes to the treatments varied between the cultivars tested. The fertigation treatments had a significant effect on the morphometric traits (width for mangetout and French bean; fresh weight for French bean; seed height for Pea cv. Lincoln). The total soluble solids and citric acid content have been shown to be increased by low soil water availability (T50) for mangetout. Fertigation treatments did not significantly affect the antioxidant compounds (total phenolic and ascorbic acid), minerals and protein fraction contents of legumes studied. Regarding legume health benefits, the most prominent cultivars were BC-033620 pea and French bean because of their high total phenolic (65 mg gallic acid equivalent 100 g⁻¹ fresh weight) and ascorbic acid content (55 mg ascorbic acid 100 g⁻¹ fresh weight), respectively. The results expand our knowledge concerning the nutraceutical quality and appropriate cultivation methods of legumes in order to make the system more sustainable and to encourage their consumption. Full article

(This article belongs to the Special Issue Horticultural Crop Response to Different Environmental and Nutritional Stress)

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13 pages, 2273 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Genomic Resource Development for Hydrangea (Hydrangea macrophylla (Thunb.) Ser.)—A Transcriptome Assembly and a High-Density Genetic Linkage Map

by Xingbo Wu, Amanda M. Hulse-Kemp, Phillip A. Wadl, Zach Smith, Keithanne Mockaitis, Margaret E. Staton, Timothy A. Rinehart and Lisa W. Alexander

Horticulturae 2021, 7(2), 25; https://doi.org/10.3390/horticulturae7020025 - 5 Feb 2021

Cited by 14 | Viewed by 5452

Abstract

Hydrangea (Hydrangea macrophylla) is an important ornamental crop that has been cultivated for more than 300 years. Despite the economic importance, genetic studies for hydrangea have been limited by the lack of genetic resources. Genetic linkage maps and subsequent trait mapping [...] Read more.

Hydrangea (Hydrangea macrophylla) is an important ornamental crop that has been cultivated for more than 300 years. Despite the economic importance, genetic studies for hydrangea have been limited by the lack of genetic resources. Genetic linkage maps and subsequent trait mapping are essential tools to identify and make markers available for marker-assisted breeding. A transcriptomic study was performed on two important cultivars, Veitchii and Endless Summer, to discover simple sequence repeat (SSR) markers and an F₁ population based on the cross ‘Veitchii’ × ‘Endless Summer’ was established for genetic linkage map construction. Genotyping by sequencing (GBS) was performed on the mapping population along with SSR genotyping. From an analysis of 42,682 putative transcripts, 8780 SSRs were identified and 1535 were validated in the mapping parents. A total of 267 polymorphic SSRs were selected for linkage map construction. The GBS yielded 3923 high quality single nucleotide polymorphisms (SNPs) in the mapping population, resulting in a total of 4190 markers that were used to generate maps for each parent and a consensus map. The consensus linkage map contained 1767 positioned markers (146 SSRs and 1621 SNPs), spanned 1383.4 centiMorgans (cM), and was comprised of 18 linkage groups, with an average mapping interval of 0.8 cM. The transcriptome information and large-scale marker development in this study greatly expanded the genetic resources that are available for hydrangea. The high-density genetic linkage maps presented here will serve as an important foundation for quantitative trait loci mapping, map-based gene cloning, and marker-assisted selection of H. macrophylla. Full article

(This article belongs to the Special Issue Breeding, Genetics and Genomics of Ornamental Plants)

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14 pages, 2969 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Bacillus spp. and Brevibacillus sp. on the Photosynthesis and Redox Status of Solanum lycopersicum

by Marino Costa-Santos, Nuno Mariz-Ponte, Maria Celeste Dias, Luísa Moura, Guilhermina Marques and Conceição Santos

Horticulturae 2021, 7(2), 24; https://doi.org/10.3390/horticulturae7020024 - 3 Feb 2021

Cited by 27 | Viewed by 5129

Abstract

Plant-growth-promoting bacteria (PGPB) are gaining attention as a sustainable alternative to current agrochemicals. This study evaluated the impact of three Bacillus spp. (5PB1, 1PB1, FV46) and one Brevibacillus sp. (C9F) on the important crop tomato (Solanum lycopersicum) using the model cv. [...] Read more.

Plant-growth-promoting bacteria (PGPB) are gaining attention as a sustainable alternative to current agrochemicals. This study evaluated the impact of three Bacillus spp. (5PB1, 1PB1, FV46) and one Brevibacillus sp. (C9F) on the important crop tomato (Solanum lycopersicum) using the model cv. ‘MicroTom’. The effects of these isolates were assessed on (a) seedlings’ growth and vigor, and (b) adult potted plants. In potted plants, several photosynthetic parameters (chlorophylls (a and b), carotenoids and anthocyanins contents, transpiration rate, stomatal conductance, net CO₂ photosynthetic rate, and intercellular CO₂ concentration, and on chlorophyll fluorescence yields of light- and dark-adapted leaves)), as well as soluble sugars and starch contents, were quantified. Additionally, the effects on redox status were evaluated. While the growth of seedlings was, overall, not influenced by the strains, some effects were observed on adult plants. The Bacillus safensis FV46 stimulated the content of pigments, compared to C9F. Bacillus zhangzhouensis 5PB1 increased starch levels and was positively correlated with some parameters of the photophosphorylation and the gas exchange phases. Interestingly, Bacillus megaterium 1PB1 decreased superoxide (O₂⁻) content, and B. safensis FV46 promoted non-enzymatic antioxidant defenses, increasing total phenol content levels. These results, conducted on a model cultivar, support the theory that these isolates differently act on tomato plant physiology, and that their activity depends on the age of the plant, and may differently influence photosynthesis. It would now be interesting to analyze the influence of these bacteria using commercial cultivars. Full article

(This article belongs to the Collection Microbe-Assisted Production of Horticultural Crops)

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14 pages, 1527 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Nutraceutical Content and Daily Value Contribution of Sweet Potato Accessions for the European Market

by Aline C. Galvao, Carlo Nicoletto, Giampaolo Zanin, Pablo F. Vargas and Paolo Sambo

Horticulturae 2021, 7(2), 23; https://doi.org/10.3390/horticulturae7020023 - 30 Jan 2021

Cited by 14 | Viewed by 4433

Abstract

Sweet potatoes (SPs) are considered by the FAO as a primary crop for “traditional agriculture” in the tropics, but in Europe, its consumption is not widespread. However, consumer demand has grown exponentially over the past five years. This study has evaluated the quality [...] Read more.

Sweet potatoes (SPs) are considered by the FAO as a primary crop for “traditional agriculture” in the tropics, but in Europe, its consumption is not widespread. However, consumer demand has grown exponentially over the past five years. This study has evaluated the quality and nutrient contents of storage roots of 29 SPs accessions to characterize their role in improving the human diet. Roots were analyzed for nutraceuticals, sugars, and minerals. Results underlined a considerable variability of nutrient content related to color among SPs accessions. The deep-orange-fleshed SPs showed a higher content of β-carotene compared to the light orange- and cream-fleshed ones; 100 g of edible product of HON86 can supply 32.3% of the daily value contribution of vitamin A, followed by the pale orange-fleshed BRA32 and BRA54. The total phenolic content of the purple ecotypes was about two to five times higher than the other genotypes. The calcium content was generally low, whereas, in many accessions, magnesium and phosphorus content reached 20%, or higher of the contribution to the daily value. Such a high variability suggests different use of the different accessions according to their strengths, but might also be used for breeding to improve quality traits of the commercial varieties. Full article

(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)

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13 pages, 1562 KiB

Open AccessEditor’s ChoiceArticle

Reassessing the Role of Potassium in Tomato Grown with Water Shortages

by Anna De Luca, Mireia Corell, Mathilde Chivet, M. Angeles Parrado, José M. Pardo and Eduardo O. Leidi

Horticulturae 2021, 7(2), 20; https://doi.org/10.3390/horticulturae7020020 - 29 Jan 2021

Cited by 14 | Viewed by 3912

Abstract

Potassium (K) is closely related to plant water uptake and use and affects key processes in assimilation and growth. The aim of this work was to find out to what extent K supply and enhanced compartmentation might improve water use and productivity when [...] Read more.

Potassium (K) is closely related to plant water uptake and use and affects key processes in assimilation and growth. The aim of this work was to find out to what extent K supply and enhanced compartmentation might improve water use and productivity when tomato plants suffered from periods of water stress. Yield, water traits, gas exchange, photosynthetic rate and biomass partition were determined. When plants suffered dehydration, increasing K supply was associated with reduction in stomatal conductance and increased water contents, but failed to protect photosynthetic rate. Potassium supplements increased shoot growth, fruit setting and yield under water stress. However, increasing the K supply could not counteract the great yield reduction under drought. A transgenic tomato line with enhanced K uptake into vacuoles and able to reach higher plant K contents, still showed poor yield performance under water stress and had lower K use efficiency than the control plants. With unlimited water supply (hydroponics), plants grown in low-K showed greater root hydraulic conductivity than at higher K availability and stomatal conductance was not associated with leaf K concentration. In conclusion, increasing K supply and tissue content improved some physiological features related to drought tolerance but did not overcome yield restrictions imposed by water stress. Full article

(This article belongs to the Special Issue Managing the Product Quality of Vegetable Crops under Abiotic Stress)

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19 pages, 861 KiB

Open AccessEditor’s ChoiceArticle

Chemical Composition, Antioxidant, and α-Glucosidase-Inhibiting Activity of Aqueous and Hydroethanolic Extracts of Traditional Antidiabetics from Croatian Ethnomedicine

by Kristina Bljajić, Andrea Brajković, Ana Čačić, Lovorka Vujić, Jasna Jablan, Isabel Saraiva de Carvalho and Marijana Zovko Končić

Horticulturae 2021, 7(2), 15; https://doi.org/10.3390/horticulturae7020015 - 26 Jan 2021

Cited by 14 | Viewed by 3785

Abstract

Type 2 diabetes (T2D) is a chronic disease with a growing prevalence worldwide. In addition to the conventional therapy, many T2D patients use phytotherapeutic preparations. In the present study, chemical composition, antioxidant, and α-glucosidase inhibiting activity of traditional antidiabetics from Croatian ethnomedicine ( [...] Read more.

Type 2 diabetes (T2D) is a chronic disease with a growing prevalence worldwide. In addition to the conventional therapy, many T2D patients use phytotherapeutic preparations. In the present study, chemical composition, antioxidant, and α-glucosidase inhibiting activity of traditional antidiabetics from Croatian ethnomedicine (Achillea millefolium, Artemisia absinthium, Centaurium erythraea, Morusalba, Phaseolus vulgaris, Sambucus nigra, and Salvia officinalis) were assessed. The efficacy of water and 80% ethanol as extraction solvents for bioactive constituents was compared. HPLC analysis revealed that the prepared extracts were rich in phenols, especially rutin, ferulic, and chlorogenic acid. Antiradical (against DPPH and ABTS radicals), reducing (towards Mo⁶⁺ and Fe³⁺ ions), and enzyme inhibiting properties were in linear correlation with the content of phenolic constituents. Ethanolic extracts, richer in phenolic substances, showed dominant efficacy in those assays. Aqueous extracts, on the other hand, were better Fe²⁺ ion chelators and more active in the β-carotene linoleic acid assay. Extracts from S. officinalis and A. millefolium were particularly active antioxidants and α-glucosidase inhibitors. A. absinthium, another potent α-glucosidase inhibitor, contained chromium, a mineral that promotes insulin action. The investigated plants contained significant amounts of minerals useful in management of T2D, with negligible amounts of heavy metals deeming them safe for human use. Full article

(This article belongs to the Special Issue Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Green, Red and Flowering Plants)

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15 pages, 996 KiB

Open AccessEditor’s ChoiceArticle

Effects of Drought on Yield and Nutraceutical Properties of Beans (Phaseolus spp.) Traditionally Cultivated in Veneto, Italy

by Pietro Sica, Aline Galvao, Francesco Scariolo, Carmelo Maucieri, Carlo Nicoletto, Cristiane Pilon, Paolo Sambo, Gianni Barcaccia, Maurizio Borin, Miguel Cabrera and Dorcas Franklin

Horticulturae 2021, 7(2), 17; https://doi.org/10.3390/horticulturae7020017 - 26 Jan 2021

Cited by 13 | Viewed by 4418

Abstract

Beans are often grown in regions with climates that are susceptible to drought during the cultivation period. Consequently, it is important to identify bean accessions tolerant to drought conditions and assess the effect of drought on seeds’ nutraceutical properties. This study evaluated the [...] Read more.

Beans are often grown in regions with climates that are susceptible to drought during the cultivation period. Consequently, it is important to identify bean accessions tolerant to drought conditions and assess the effect of drought on seeds’ nutraceutical properties. This study evaluated the effect of drought during different development stages (NES = never stressed; ALS = always stressed; SBF = stressed before flowering; SAF = stressed after flowering) on the yield and nutraceutical properties of six local bean varieties: Fasolo del Diavolo, Gialet, Posenati, Secle, D’oro, and Maron. Analysis of variance indicated that Gialet was not significantly affected by drought treatments, and Posenati under SBF and NES treatments had greater yields than under ALS and SAF treatments, whereas Secle under SBF produced 80% more seeds than under NES. Total phenols, antioxidant capacity, and calcium content were significantly different among the local varieties. Yield was significantly and positively correlated with seed calcium content and significantly and negatively correlated with protein, total phenols, and antioxidant capacity. The interaction between local varieties and treatment significantly affected seeds’ Zn content. Gialet and Maron seeds’ Zn contents were about 60 mg kg⁻¹, almost double the average of commercial varieties. In summary, this study paves the way to the identification of potential bean varieties resistant to drought. Further molecular studies will help support these findings. Full article

(This article belongs to the Special Issue Managing the Product Quality of Vegetable Crops under Abiotic Stress)

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16 pages, 1693 KiB

Open AccessEditor’s ChoiceArticle

Fertilization and Pre-Sowing Seed Soaking Affect Yield and Mineral Nutrients of Ten Microgreen Species

by Tongyin Li, Geoffrey T. Lalk and Guihong Bi

Horticulturae 2021, 7(2), 14; https://doi.org/10.3390/horticulturae7020014 - 25 Jan 2021

Cited by 27 | Viewed by 5796

Abstract

Microgreens, vegetable or herb seedlings consumed at a young growth stage, are considered to be a functional food with high concentrations of mineral nutrients and healthy beneficial bioactive compounds. The production of microgreens has been increasing in recent years. Vegetable growers are interested [...] Read more.

Microgreens, vegetable or herb seedlings consumed at a young growth stage, are considered to be a functional food with high concentrations of mineral nutrients and healthy beneficial bioactive compounds. The production of microgreens has been increasing in recent years. Vegetable growers are interested in growing microgreens as a new specialty crop due to their high market value, popularity, and short production cycles. However, there is a lack of research-based crop-specific recommendations for cultural practices including fertilization, pre-sowing seed treatments, and their effects on nutritional facts of microgreens. Ten microgreen species were evaluated for their shoot growth and mineral nutrient concentrations as affected by one-time post-emergence fertilization and pre-sowing seed soaking in two repeated experiments, from November 2018 to January 2019, in a greenhouse. The microgreen species varied in fresh and dry shoot weights, shoot height, visual rating, as well as macro- and micro-nutrient concentrations. Fertilization with a general-purpose soluble fertilizer (20-20-20 with micronutrients) at a rate of 100 mg·L⁻¹ nitrogen (N) increased fresh shoot weight, and macro- and micro-nutrient concentrations in one or both experiments, with the exception of decreasing concentrations of calcium (Ca), magnesium (Mg), and manganese (Mn). Seed soaking consistently decreased fresh or dry shoot weight and nutrient concentrations when there was a significant effect. Full article

(This article belongs to the Section Protected Culture)

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11 pages, 11207 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Reduced Iris Yellow Spot Symptoms through Selection within Onion Breeding Lines

by Neel Kamal, Seyed Shahabeddin Nourbakhsh and Christopher S. Cramer

Horticulturae 2021, 7(2), 12; https://doi.org/10.3390/horticulturae7020012 - 22 Jan 2021

Cited by 7 | Viewed by 3629

Abstract

Iris yellow spot (IYS) disease in onion (Allium cepa L.) is caused by onion thrips (Thrips tabaci L.) vectored Iris yellow spot virus (IYSV). The absence of cultivars that are resistant/tolerant to thrips and/or IYS is a challenge for onion bulb [...] Read more.

Iris yellow spot (IYS) disease in onion (Allium cepa L.) is caused by onion thrips (Thrips tabaci L.) vectored Iris yellow spot virus (IYSV). The absence of cultivars that are resistant/tolerant to thrips and/or IYS is a challenge for onion bulb and seed production worldwide. To measure selection progress for reduced/delayed IYS symptom expression in onion breeding lines after two selection cycles, selections were performed in 2011 on previously evaluated lines that exhibited a reduced symptom expression after one selection cycle. Selected plants from each line were massed in a cage and the resulted progenies were evaluated in 2013 and 2014 along with their original populations and a susceptible check—’Rumba’. In some comparisons, the selection progress for delayed/reduced IYS symptom expression was observed for some breeding lines. Plants of most selected breeding lines exhibited less disease expression than plants of ‘Rumba’. For some selections, a low disease severity was observed even with a relatively high number of thrips per plant. These results suggest that further improvement might be achievable with additional cycles of selection. Full article

(This article belongs to the Special Issue Advances in Allium Breeding and Genetics)

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12 pages, 288 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Tree Planting Density and Canopy Position Affect ‘Cerasuola’ and ‘Koroneiki’ Olive Oil Quality

by Filipa Grilo, Sahar Sedaghat, Vita Di Stefano, Raffaele Sacchi, Tiziano Caruso and Riccardo Lo Bianco

Horticulturae 2021, 7(2), 11; https://doi.org/10.3390/horticulturae7020011 - 20 Jan 2021

Cited by 13 | Viewed by 3639

Abstract

To maximize orchard production and tree crop efficiency, optimization of both maximum orchard light interception and radiation distribution within the tree canopy are important strategies. To study the influence of planting density and fruit position within the canopy on oil quality from ‘Cerasuola’ [...] Read more.

To maximize orchard production and tree crop efficiency, optimization of both maximum orchard light interception and radiation distribution within the tree canopy are important strategies. To study the influence of planting density and fruit position within the canopy on oil quality from ‘Cerasuola’ and ‘Koroneiki’ olive (Olea europaea L.), fruits were harvested from the upper and lower canopy layers of trees in hedgerow planting systems at two densities: High at 1000 trees ha⁻¹ (HD) and Medium at 500 trees ha⁻¹ (MD). Tree crop efficiency and fruit weight, water and fat content were measured together with olive oil standard quality parameters, phenolic and volatile composition. Fruits in the upper layers of the canopy always showed a higher maturity index, 6% more fat content, and 4% less water content than lower layers. Upper layers of HD trees showed the highest phenol content, whereas lower layers of MD trees showed the lowest phenol content (36% less than the upper layers of HD). HD trees showed the largest differences in fruit maturation, water and fat content between upper and lower canopy positions, increasing quality and oil yield variability at harvest. ‘Koroneiki’ showed more stable oils with a 28% higher MUFA/PUFA ratio and 12% higher phenol content than ‘Cerasuola’ oils. This study provides further evidence of the fact that cultivar, planting density, and canopy architecture may be strong determinants of olive oil yield and composition in hedgerow planting systems. Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae Ⅱ)

12 pages, 1136 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Drying Methods on Phenolic Compounds and Antioxidant Activity of Urtica dioica L. Leaves

by Leani Martìnez Garcìa, Costanza Ceccanti, Carmine Negro, Luigi De Bellis, Luca Incrocci, Alberto Pardossi and Lucia Guidi

Horticulturae 2021, 7(1), 10; https://doi.org/10.3390/horticulturae7010010 - 19 Jan 2021

Cited by 62 | Viewed by 7801

Abstract

Stinging nettle (Urtica dioica) is a plant well known in traditional medicine for its many beneficial properties, but the lack of standardization regarding the product to offer to consumers limits its diffusion. To this end, drying appears to be a useful [...] Read more.

Stinging nettle (Urtica dioica) is a plant well known in traditional medicine for its many beneficial properties, but the lack of standardization regarding the product to offer to consumers limits its diffusion. To this end, drying appears to be a useful technique to offer a low-cost product that can be stored for long time, but the different drying procedures may give rise to end-products of very different quality as nutraceutical and antioxidant compounds. Nettle leaves have been dehydrated employing freeze-drying (FD), oven-drying (OD) or heat pump drying (HPD) and compared with fresh leaves following water extraction to emulate the use by final consumers. Results indicate that the best dehydration technique is HPD, which apparently gives rise to more than a doubling of total phenols and antioxidant activity in the extract compared to the water extract obtained from fresh leaves but a reduction in the level of ascorbic acid of about 39%. In addition, the content of some phenolic compounds is 10 to over a hundred times higher in the extract after HPD than that obtained from fresh samples. This confirms that the dehydration technique should be tuned in relation to the compounds of greatest interest or value. Full article

(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)

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13 pages, 1039 KiB

Open AccessFeature PaperEditor’s ChoiceReview

UV Lighting in Horticulture: A Sustainable Tool for Improving Production Quality and Food Safety

by Danilo Loconsole and Pietro Santamaria

Horticulturae 2021, 7(1), 9; https://doi.org/10.3390/horticulturae7010009 - 17 Jan 2021

Cited by 57 | Viewed by 17745

Abstract

Ultraviolet (UV) is a component of solar radiation that can be divided into three types defined by waveband: UV-A (315–400 nm), UV-B (280–315 nm), and UV-C (<280 nm). UV light can influence the physiological responses of plants. Wavelength, intensity, and exposure have a [...] Read more.

Ultraviolet (UV) is a component of solar radiation that can be divided into three types defined by waveband: UV-A (315–400 nm), UV-B (280–315 nm), and UV-C (<280 nm). UV light can influence the physiological responses of plants. Wavelength, intensity, and exposure have a great impact on plant growth and quality. Interaction between plants and UV light is regulated by photoreceptors such as UV Resistance Locus 8 (UVR8) that enables acclimation to UV-B stress. Although UV in high doses is known to damage quality and production parameters, some studies show that UV in low doses may stimulate biomass accumulation and the synthesis of healthy compounds that mainly absorb UV. UV exposure is known to induce variations in plant architecture, important in ornamental crops, increasing their economic value. Abiotic stress induced by UV exposure increases resistance to insects and pathogens, and reduce postharvest quality depletion. This review highlights the role that UV may play in plant growth, quality, photomorphogenesis, and abiotic/biotic stress resistance. Full article

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12 pages, 305 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Nutritional Characterization and Storage Ability of Salicornia ramosissima and Sarcocornia perennis for Fresh Vegetable Salads

by Maria Dulce Antunes, Custódia Gago, Adriana Guerreiro, Ana Rita Sousa, Miriam Julião, Maria Graça Miguel, Maria Leonor Faleiro and Thomas Panagopoulos

Horticulturae 2021, 7(1), 6; https://doi.org/10.3390/horticulturae7010006 - 8 Jan 2021

Cited by 39 | Viewed by 5382

Abstract

The aim of this work was to study the potential of two halophytes for fresh salads. Sarcocornia perennis (SAR) and Salicornia ramosissima (SAL) plant tips were harvested in May and July, and stored at 4 °C for 14 days. At harvest, mineral analyses [...] Read more.

The aim of this work was to study the potential of two halophytes for fresh salads. Sarcocornia perennis (SAR) and Salicornia ramosissima (SAL) plant tips were harvested in May and July, and stored at 4 °C for 14 days. At harvest, mineral analyses (Na, K, Mg, Ca, P, N, Fe, Zn, Cu, Pb and Cd), chlorophyll content, protein, β-carotene and ascorbic acid were performed. Color (CIELab), phenolics, antioxidant activity and microbial contamination were measured at harvest and after 14 days storage at 4 °C, and a taste panel evaluated the products. SAL had generally slightly higher values of vitamin C, phenols and carotenoids than SAR. In SAR after 14 days of storage, the levels of phenols and the antioxidant activity were higher than at harvest, both in May and July. The opposite was observed for SAL. In this case, only the antioxidant activity was higher after 14 days of storage. Microbial contamination was very low, not reaching even half of critical limits. Both halophytes had good nutritional value, being suitable for use as fresh salads which can be stored for up to 14 days at 4 °C. SAR seems to be a better source of antioxidants, Ca and Fe than SAL and has less general quality and nutritional value changes from harvest time through cold storage. Fresh tips of both halophytes showed better appearance and nutritional quality when harvested in the early season (May) than at the end of the season (July). Full article

(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)

12 pages, 1430 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Secondary Metabolite Contents and Metabolic Profiles of Six Lycoris Species

by Hyeon Ji Yeo, Ye Jin Kim, Bao Van Nguyen, Ye Eun Park, Chang Ha Park, Haeng Hoon Kim, Jae Kwang Kim and Sang Un Park

Horticulturae 2021, 7(1), 5; https://doi.org/10.3390/horticulturae7010005 - 5 Jan 2021

Cited by 6 | Viewed by 4101

Abstract

Quantitative HPLC analysis was performed on six different species of Lycoris herbs to investigate variation in phytochemical content, especially galantamine and phenylpropanoid-derived compounds. The contents of these compounds differed widely among the Lycoris species, with L. radiata and L. chinensis containing the lowest [...] Read more.

Quantitative HPLC analysis was performed on six different species of Lycoris herbs to investigate variation in phytochemical content, especially galantamine and phenylpropanoid-derived compounds. The contents of these compounds differed widely among the Lycoris species, with L. radiata and L. chinensis containing the lowest and highest galantamine contents, respectively. Specifically, the galantamine content of L. radiata was 62.5% higher than that of L. chinensis. Following L. radiata, L. sanguinea contained the next highest galantamine content, which was 59.1% higher than that of L. chinensis. Furthermore, a total of 12 phenylpropanoid-derived compounds were found in the different Lycoris species, where L. sanguinea, L. squamigera, and L. uydoensis had the largest accumulation of these compounds. The total phenylpropanoid content of L. sanguinea was the highest, while that of L. radiata was the lowest. Seven of the phenylpropanoid-derived compounds, rutin, quercetin, catechin, epicatechin gallate, chlorogenic acid, benzoic acid, and kaempferol, were dominant. L. sanguinea, L. uydoensis, and L. squamigera showed amounts of these seven compounds that were 5–6 times greater than those of the other species in the study. To the best of our knowledge, our results provide the most detailed phytochemical information on these species to date, which is valuable for future applications using these medicinal plants. Full article

(This article belongs to the Special Issue Biodiversity, Production, Processing and Quality along the Chain of Herbal and Edible Flowers)

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11 pages, 1497 KiB

Open AccessEditor’s ChoiceArticle

Freezing Tolerance and Chilling Fulfillment Differences in Cold Climate Grape Cultivars

by Turhan Yilmaz, Dilmini Alahakoon and Anne Fennell

Horticulturae 2021, 7(1), 4; https://doi.org/10.3390/horticulturae7010004 - 30 Dec 2020

Cited by 6 | Viewed by 5078

Abstract

Grapevine sustainability is impacted by the timing of dormancy initiation and freezing tolerance in fall and winter and chilling fulfillment and bud break in the spring. These traits have genetic and local temperature contributing factors; therefore, this study was undertaken to develop an [...] Read more.

Grapevine sustainability is impacted by the timing of dormancy initiation and freezing tolerance in fall and winter and chilling fulfillment and bud break in the spring. These traits have genetic and local temperature contributing factors; therefore, this study was undertaken to develop an understanding of these characteristics in four recently developed cold climate cultivars. The cold hardiness and chilling fulfillment profiles were monitored in Brianna, Frontenac gris, La Crescent and Marquette using differential thermal analyses and bud break assays. Bud cold hardiness of all cultivars increased with the declining temperatures from November through February, after which the buds began to lose freezing tolerance. There were significant differences in cold hardiness and chilling fulfillment between cultivars during the endodormant and ecodormant period of winter. Marquette had the greatest freezing tolerance from early November through midwinter suggesting it has potential as a sentinel cultivar for comparisons of new cold climate selections. Brianna was slower to acclimate and deacclimated more rapidly than the other cultivars. Chilling fulfillment under natural field or constant 4 °C conditions showed no main effect differences for chilling accumulation condition; however, there were significant cultivar, condition, and time point interactions, indicating the cultivars differed in chilling fulfillment responses. Full article

(This article belongs to the Special Issue Grape Responses to Abiotic and Biotic Stresses)

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18 pages, 10243 KiB

Open AccessEditor’s ChoiceArticle

Spatial and Temporal Enhancement of Colour Development in Apples Subjected to Reflective Material in the Southern Hemisphere

by Kerstin Funke and Michael Blanke

Horticulturae 2021, 7(1), 2; https://doi.org/10.3390/horticulturae7010002 - 27 Dec 2020

Cited by 13 | Viewed by 3982

Abstract

(1) Background: Climate change associated with a warm autumn often hampers the development of colouration of many fruits including late ripening apple varieties in New Zealand. (2) Objective: This study will provide detailed information on the possibility of enhancing colouration of apples under [...] Read more.

(1) Background: Climate change associated with a warm autumn often hampers the development of colouration of many fruits including late ripening apple varieties in New Zealand. (2) Objective: This study will provide detailed information on the possibility of enhancing colouration of apples under the diffuse light conditions in autumn in the southern hemisphere (SH). The aim is to obtain a larger proportion of fruit meeting the (red) colour market specifications, especially within the first picks, and to identify both the side of the fruit and its position within the tall trees canopy (3.5 m) as affected by reflective mulch on the ground spread at and over different times. (3) Material and methods: Reflective white textile mulch (Extenday^®) was spread in the grassed alleyways 4 weeks or 2 weeks before the anticipated harvest in April on cv. Fuji and Pacific Rose apple trees without hail nets in the Northern Part of the South Island (41° S) of NZ. Fruit colour (blush) was determined by scoring and colourimeter during fruit maturation and at harvest, and fruit quality was determined at harvest by standard methods. (4) Results: (a) In cv. Pacific Rose apple, the reflective mulch increased the scored blush value from 1.5 (<50% blush) to 3.9 (ca. 75% blush) before the first pick, whereas the control fruit (without Extenday^R) reached a final score value of only 3.0. (b) Fruit colour improved after one week of exposure to reflective mulch in the SH. (c) The scored blush on fruit near the trunk with reflective mulch doubled (Pacific Rose) or tripled (Fuji) at harvest in comparison with trees with grass alleyways (control). (d) Two and four weeks of reflective mulch enhanced colouration of the down facing side for fruit of both cultivars, especially for fruit from the inside of the canopy near the tree trunk. However, reflective mulch significantly improved blush by 20% on fruit from the periphery of the canopies of the tall trees in both cultivars without significantly affecting fruit firmness, soluble solids, starch breakdown or ripeness. (5) Conclusions: The results from ca. 2000 colour measurements showed that the short exposure of at least two weeks of reflective mulch was sufficient for enhancing colouration for outside, inside and down facing sides of the fruit of both cultivars. As a result of this surprisingly short and efficient exposure time for these tall trees (3.5 m), the reflective mulch increased the portion of fruit harvested in the first pick by 8% (Fuji) and by 27% (Pacific Rose) with improved fruit storability or export quality and thereby increased financial returns to the grower in the SH. Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae)

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14 pages, 1784 KiB

Open AccessEditor’s ChoiceArticle

Improvement of Growth and Morphology of Vegetable Seedlings with Supplemental Far-Red Enriched LED Lights in a Plant Factory

by Hyunseung Hwang, Sewoong An, Byungkwan Lee and Changhoo Chun

Horticulturae 2020, 6(4), 109; https://doi.org/10.3390/horticulturae6040109 - 21 Dec 2020

Cited by 26 | Viewed by 6246

Abstract

Although light-emitting diode (LED) lamps have been broadly applied in horticultural production to improve plant yield and quality, compared to natural light there is a disadvantage in the lack of far-red light in the LED spectrum. Far-red light has been studied widely to [...] Read more.

Although light-emitting diode (LED) lamps have been broadly applied in horticultural production to improve plant yield and quality, compared to natural light there is a disadvantage in the lack of far-red light in the LED spectrum. Far-red light has been studied widely to control plant growth and development. Therefore, this study aimed to find the effect of supplemental far-red-enriched LED lights to control the growth of tomato, red pepper, cucumber, gourd, watermelon and bottle gourd seedlings. The treatments were cool white LED:far-red LED at ratios of 5:0, 5:1, 5:2 and 5:3. The growth of tomato and red pepper seedlings, including hypocotyl length, was correlated to far-red light and light intensity. The phytochrome photostationary state (PSS) value of maximum hypocotyl length by supplemental far-red-enriched light ranged from 0.69 to 0.77 in tomato and red pepper seedlings. Although hypocotyl lengths of cucumber and watermelon were greatly affected by PSS, the PSS value for maximum hypocotyl length was lower than for tomato and red pepper. These results show that manipulating supplemental far-red enrichment can be used to control vegetable seedling growth with some variation among plant species. Full article

(This article belongs to the Section Vegetable Production Systems)

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18 pages, 4638 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Characterization of Cucumber (Cucumis sativus L.) GRAS Genes and Their Response to Various Abiotic Stresses

by Caixia Li, Shaoyun Dong, Xiaoping Liu, Kailiang Bo, Han Miao, Diane M. Beckles, Shengping Zhang and Xingfang Gu

Horticulturae 2020, 6(4), 110; https://doi.org/10.3390/horticulturae6040110 - 21 Dec 2020

Cited by 12 | Viewed by 4480

Abstract

The GRAS (gibberellic acid insensitive, repressor of GAI, and scarecrow) proteins are a family of plant-specific transcription factors that regulate plant growth, development, and stress response. Currently, the role of GRAS transcription factors in various abiotic stress responses has [...] Read more.

The GRAS (gibberellic acid insensitive, repressor of GAI, and scarecrow) proteins are a family of plant-specific transcription factors that regulate plant growth, development, and stress response. Currently, the role of GRAS transcription factors in various abiotic stress responses has not been systematically studied in cucumber (Cucumis sativus L.), a popular vegetable crop. Here, we provide a comprehensive bioinformatics analysis of the 35 GRAS genes identified in the cucumber genome. In this study, cucumber genotypes, i.e., “CG104”, which is stress-tolerant, and genotype “CG37”, which is stress-sensitive, were examined to provide insight on potential differences in the GRAS-regulated abiotic stress pathways. Transcriptional analysis by RNA-seq or qRT-PCR of these two genotypes revealed common and divergent functions of CsGRAS genes regulated by low and high temperatures, salinity, and by exposure to the phytohormones gibberellin (GA) and abscisic acid (ABA). Notably, CsGRAS2 (DELLA) and CsGRAS26 (LISCL) were regulated by all abiotic stresses and hormone treatments, suggesting that they may function in the biological cross-talk between multiple signaling pathways. This study provides candidate genes for improving cucumber tolerance to various environmental stresses. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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13 pages, 839 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Influences of Postharvest Storage and Processing Techniques on Antioxidant and Nutraceutical Properties of Rubus idaeus L.: A Mini-Review

by Ermes Lo Piccolo, Leani Martìnez Garcìa, Marco Landi, Lucia Guidi, Rossano Massai and Damiano Remorini

Horticulturae 2020, 6(4), 105; https://doi.org/10.3390/horticulturae6040105 - 16 Dec 2020

Cited by 11 | Viewed by 4437

Abstract

The growth of agricultural mechanization has promoted an increase in raspberry production, and for this reason, the best postharvest storage and processing techniques capable of maintaining the health beneficial properties of these perishable berry fruits have been widely studied. Indeed, raspberries are a [...] Read more.

The growth of agricultural mechanization has promoted an increase in raspberry production, and for this reason, the best postharvest storage and processing techniques capable of maintaining the health beneficial properties of these perishable berry fruits have been widely studied. Indeed, raspberries are a rich source of bioactive chemical compounds (e.g., ellagitannins, anthocyanins, and ascorbic acid), but these can be altered by postharvest storage and processing techniques before consumption. Although there are clear differences in storage times and techniques, the content of bioactive chemical compounds is relatively stable with some minor changes in ascorbic acid or anthocyanin content during cold (5 °C) or frozen storage. In the literature, processing techniques such as juicing or drying have negatively affected the content of bioactive chemical compounds. Among drying techniques, hot air (oven) drying is the process that alters the content of bioactive chemical compounds the most. For this reason, new drying technologies such as microwave and heat pumps have been developed. These novel techniques are more successful in retaining bioactive chemical compounds with respect to conventional hot air drying. This mini-review surveys recent literature concerning the effects of postharvest storage and processing techniques on raspberry bioactive chemical compound content. Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae)

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11 pages, 2747 KiB

Open AccessEditor’s ChoiceArticle

Indices for the Assessment of Glycoalkaloids in Potato Tubers Based on Surface Color and Chlorophyll Content

by Shimeles Tilahun, Hee Sung An, Tifsehit Solomon, Min Woo Baek, Han Ryul Choi, Hee Cheol Lee and Cheon Soon Jeong

Horticulturae 2020, 6(4), 107; https://doi.org/10.3390/horticulturae6040107 - 16 Dec 2020

Cited by 6 | Viewed by 3860

Abstract

Glycoalkaloids (GAs) are toxic to humans at higher concentrations. However, studies also suggest the health benefits of GAs depending on the dose and conditions of use. Methods that have been used to determine GA content in potato tubers are destructive and time-consuming and [...] Read more.

Glycoalkaloids (GAs) are toxic to humans at higher concentrations. However, studies also suggest the health benefits of GAs depending on the dose and conditions of use. Methods that have been used to determine GA content in potato tubers are destructive and time-consuming and require skilled personnel and high-performance laboratory equipment. We conducted this study to develop indices for the prediction of the level of total GAs in potato tubers at different greening stages based on surface color readings and chlorophyll (Chl) development. Color values (Hunter L*, a*, b*, a*/b*), Chls (Chl a, Chl b, and total Chls) and GA (α-solanine, α-chaconine, and total GAs) content were measured from tubers of ‘Atlantic’ and ‘Trent’ potato cultivars at three-week intervals in up to six greening stages during the storage at room conditions (22 °C, 12-h shift of light-dark cycles). The results have revealed that greening, Chls, and GA content significantly increased for the two cultivars as the stage proceeded. The toxic level of GAs (>200 mg kg⁻¹ FW) was accumulated at the late greening stages, accompanied by the highest Chl content. Finally, indices were developed based on surface color and Chl content for estimation of the safe GA levels for the consumption of the two commercially and commonly used potato cultivars. Moreover, the developed indices could be used as basic information to adapt to other potato cultivars. Full article

(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)

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15 pages, 1717 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Correlations among Quality Characteristics of Green Asparagus Affected by the Application Methods of Elevated CO₂ Combined with MA Packaging

by Li-Xia Wang, In-Lee Choi and Ho-Min Kang

Horticulturae 2020, 6(4), 103; https://doi.org/10.3390/horticulturae6040103 - 14 Dec 2020

Cited by 6 | Viewed by 3894

Abstract

This research investigated the effects of continuous elevated CO₂ (20%, (v/v)) application or a 3 day CO₂ pretreatment followed by modified atmosphere (MA) or micro-perforated (MP) packaging on the postharvest quality of asparagus. The combination of CO₂ pretreatment with MA packaging [...] Read more.

This research investigated the effects of continuous elevated CO₂ (20%, (v/v)) application or a 3 day CO₂ pretreatment followed by modified atmosphere (MA) or micro-perforated (MP) packaging on the postharvest quality of asparagus. The combination of CO₂ pretreatment with MA packaging (Pre-MA) inhibited the yellowing of asparagus and fresh weight loss (FWL), whereas stem firmness slightly increased with all elevated CO₂ treatments. CO₂ pretreatments increased antioxidant activity in the stem, but not in the tip, in contrast to the continuous flow CO₂ (Flow-CO₂) treatment. The phenolic and flavonoid contents increased in the elevated CO₂ pretreatments and Flow-CO₂ treatment. The elevated CO₂ treatments, especially Flow-CO₂, inhibited the development of microorganisms, and the treated asparagus did not decay. Pre-MA and Flow-CO₂ treatments were more effective in maintaining the visual quality and retarding the off-odor of asparagus. Furthermore, significant correlations between sensory quality characteristics and physiological-biochemical attributes were recognized; three principal components were extracted and they explained 86.4% of asparagus characteristics. The results confirmed the importance of visual quality, off-odor, firmness, color parameters, SSC and total phenolic content. In conclusion, elevated CO₂ pretreatment followed by MA packaging (Pre-MA) was beneficial for extending asparagus cold storage shelf life, and Flow-CO₂ was the best treatment for inhibiting postharvest decay. Full article

(This article belongs to the Special Issue Managing the Product Quality of Vegetable Crops under Abiotic Stress)

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8 pages, 423 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Efficacy of Orange Essential Oil and Citral after Exposure to UV-C Irradiation to Inhibit Penicillium digitatum in Navel Oranges

by Mohammad M. Rahman, Ron B. H. Wills, Michael C. Bowyer, John B. Golding, Timothy Kirkman and Penta Pristijono

Horticulturae 2020, 6(4), 102; https://doi.org/10.3390/horticulturae6040102 - 14 Dec 2020

Cited by 11 | Viewed by 3500

Abstract

The effect of UV-C irradiation on antifungal properties of orange essential oil (EO) against Penicillium digitatum in inoculated Navel oranges was examined. The UV-C irradiation of orange EO resulted in a 20% loss of the major constituent, limonene, and the generation of three [...] Read more.

The effect of UV-C irradiation on antifungal properties of orange essential oil (EO) against Penicillium digitatum in inoculated Navel oranges was examined. The UV-C irradiation of orange EO resulted in a 20% loss of the major constituent, limonene, and the generation of three hydroperoxide oxidation products, (2S,4R)-p-mentha-6,8-diene-2-hydroperoxide,(1S,4R)-p-mentha-2,8-diene-1-hydroperoxide, and (1R,4R)-p-mentha-2,8-diene-1-hydroperoxide. The P. digitatum growth in oranges dipped in non-irradiated orange EO at 1000–4000 µL L⁻¹ was not significantly different to control the fruit. Dipping in UV-C treated orange EO inhibited the growth of P. digitatum with 4000 µL L⁻¹ having the greatest effect. No phytotoxic injury to the rind was observed at any concentration. Citral, as a known antifungal chemical, was included for comparison. The non-irradiated citral (1000 µL L⁻¹) was more effective than irradiated orange EO, but elicited rind phytotoxicity. The irradiated citral was less effective in inhibiting P. digitatum growth with the loss of citral, but not hydroperoxide formation. These results suggest UV-C irradiated orange EO as a potential alternative to synthetic fungicides to inhibit P. digitatum decay. The source of orange EO could be waste flavedo generated by the orange juice processing industry. Full article

(This article belongs to the Special Issue Explorations in Postharvest Diseases of Fruits and Vegetables)

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