Advanced Studies in Abiotic Stress Response Mechanism of Horticultural Plants

A special issue of Horticulturae (ISSN 2311-7524). This special issue belongs to the section "Biotic and Abiotic Stress".

Deadline for manuscript submissions: 31 August 2024 | Viewed by 11107

Special Issue Editors


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Guest Editor
Institute for the Conservation and Improvement of Valencian Agrodiversity (COMAV, UPV), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
Interests: abiotic stress tolerance; plant environmental stress physiology; drought and salt stress; climate change; plant biochemistry; ecophysiology; oxidative stress biomarkers and reactive oxygen species; plant ecology; endemic species; invasive alien species

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Guest Editor
Plant Biology & Soil Science Department, Universidade de Vigo, 36310 Vigo, Spain
Interests: plant ecophysiology, environmental impact assessment, land degradation and marginal environmental study; screening, selection and genotypic evaluation in the plant–soil–environment nexus through agronomic tools and physiological perspective; environmental sustainability; non-conventional water resources; crop diversification; plant abiotic stress study; bio-herbicide potential of natural compounds
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Guest Editor
Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, International Crop Research Center for Stress Resistance, School of Life Sciences, Guangzhou University, Guangzhou 510642, China
Interests: abiotic stress resistance; disease resistance; domestication and improvement of crop plants; heat and drought stress; transcriptomics; genome-wide association study (GWAS); quantitative trait loci (QTLs); plant physiology; climate change; germplasm evaluation

Special Issue Information

Dear Colleagues,

Abiotic stress has a significantly negative impact on the productivity and survival of the main agricultural crops and ornamental plants. Current trends in climate change predict an increase in the severity and frequency of climatic phenomena and adverse environmental conditions, such as drought, water and soil salinity, as well as extreme temperatures, causing oxidative stress in plants.

Plants have developed several strategies to overcome abiotic stress, adopting a mechanism that allows them to survive adverse conditions. Therefore, many plants, especially tolerant species, can detect abiotic stress and elicit an appropriate response. These response mechanisms range from morphological and anatomical adaptations in organs to changes in physiological and biochemical processes. These adversely affect the plant’s growth and productivity and cause interference in stress tolerance and adaptation. Reactive oxygen species (ROS) are created in plant cells as a result of these stresses, which also cause oxidative damage. Plant defense against oxidative damage includes the activation of antioxidant enzymes and the buildup of complementary solutes that efficiently scavenge ROS. However, harmful degenerative processes do happen if the amount of activated oxygen produced surpasses the plant's ability to detoxify it; typical symptoms include loss of osmotic responsiveness, wilting, and necrosis. Plants must be able to sense, analyze, and translate various stimuli into adaptive responses, when faced with stressful situations imposed by shifting environmental variables that affect their growth and development during their life cycle.

The current Special Issue of Horticulturae aims to analyze the response mechanisms involved in plant tolerance to different types of abiotic stress, such as drought, soil salinity or high temperatures, among others, as well as in the recovery process when the stress situation is relieved.

Dr. Sara González-Orenga
Dr. M. Iftikhar Hussain
Dr. Muhammad Ikram
Guest Editors

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Keywords

  • abiotic stress
  • drought stress
  • salt stress
  • climate change
  • growth parameters
  • oxidative stress markers
  • antioxidant compounds
  • stress responsive genes
  • transcriptomic

Published Papers (11 papers)

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Research

19 pages, 15235 KiB  
Article
Genome-Wide Identification of the DGK Gene Family in Kiwifruit (Actinidia valvata Dunn) and an Expression Analysis of Their Responses to Waterlogging Stress
by Meijuan Zhang, Cuixia Liu, Faming Wang, Shibiao Liu, Jianyou Gao, Jiewei Li, Quanhui Mo, Kaiyu Ye, Beibei Qi and Hongjuan Gong
Horticulturae 2024, 10(4), 310; https://doi.org/10.3390/horticulturae10040310 - 22 Mar 2024
Viewed by 588
Abstract
Diacylglycerol kinase (DGK) is a lipid kinase that phosphorylates diacylglycerol (DAG) to generate phosphatidic acid (PA). Based on converting one important signaling molecule (DAG) to another (PA), DGK plays an important role in plant responses to abiotic stress, including waterlogging stress. However, no [...] Read more.
Diacylglycerol kinase (DGK) is a lipid kinase that phosphorylates diacylglycerol (DAG) to generate phosphatidic acid (PA). Based on converting one important signaling molecule (DAG) to another (PA), DGK plays an important role in plant responses to abiotic stress, including waterlogging stress. However, no studies have been reported on the characterization of the DGK gene family in the waterlogging-tolerant kiwifruit germplasm Actinidia valvata Dunn. In this study, we identified 18 AvDGK genes in the A. valvata genome. The phylogenetic analysis showed that AvDGKs can be classified into three clusters, and members within the same cluster have similar domain distributions, exon-intron structures, and conserved motif compositions. The chromosome localization analysis revealed that all AvDGK genes are located across 18 different chromosomes. There were 29 duplicated gene pairs in A. valvata and all had undergone purifying selection during evolution. The promoter cis-element analysis revealed that the cis-elements within AvDGK genes are associated with multiple functions, including phytohormone signal transduction, stress responses, and plant growth and development. The expression pattern analyses indicated that AvDGKs play important roles in fruit development and plant responses to waterlogging stress. The AvDGK gene family in the tetraploid A. valvata genome might promote PA synthesis and subsequent signal transduction both under short- and long-term waterlogging stresses. These results provide information regarding the structural characteristics and potential function of AvDGK genes within A. valvata and lay a fundamental basis for further research into breeding to enhance the kiwifruit’s tolerance to waterlogging stress. Full article
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19 pages, 5246 KiB  
Article
Evaluation of the Allelopathic Activity of Aqueous and Methanol Extracts of Heliotropium indicum Leaves and Roots on Eight Cucurbit Crops
by Pervin Akter, Tahera Siddiqua, Rabeya Begum and A. M. Abu Ahmed
Horticulturae 2024, 10(2), 135; https://doi.org/10.3390/horticulturae10020135 - 30 Jan 2024
Viewed by 858
Abstract
Allelopathy, a biological phenomenon where plants release chemicals that influence the growth and development of neighboring flora, offers potential natural alternatives for weed management in agriculture. This study investigated the allelopathic effects of Heliotropium indicum leaf and root extracts on the germination, growth, [...] Read more.
Allelopathy, a biological phenomenon where plants release chemicals that influence the growth and development of neighboring flora, offers potential natural alternatives for weed management in agriculture. This study investigated the allelopathic effects of Heliotropium indicum leaf and root extracts on the germination, growth, and biochemical parameters of eight cucurbit crops. Results demonstrated that H. indicum extracts generally inhibited seed germination across all cucurbit species, with aqueous extracts showing a stronger effect than methanol extracts in Lagenaria siceraria at 10.66 ± 0.46% (p < 0.001). The treatment also variably affected shoot and root growth, indicating both inhibitory and stimulatory actions, depending on the crop species and extract type. For instance, in methanol extract treatments, Benincasa hispida’s shoot length was significantly reduced, compared to the control, at 2.1 ± 0.14 cm (p < 0.001). Notably, aqueous leaf extracts enhanced chlorophyll content more effectively than root extracts, suggesting a potential application as a biostimulant, to improve photosynthetic efficiency in certain species, for example, Momordica charantia (p < 0.05). The study further explored the antioxidative potential of the extracts by measuring MDA levels, a biomarker for oxidative stress. MDA levels increased significantly across all species in response to both types of extracts, indicating oxidative stress (L. siceraria p < 0.05). These findings suggest the potential of H. indicum extracts as natural herbicides and biostimulants, though their effects are species-specific and dependent on concentration. This research contributes to understanding the complex interactions in plant allelopathy, and highlights the potential of plant-derived extracts in sustainable agriculture. Full article
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28 pages, 3920 KiB  
Article
Assessment of Phytotoxicity in Untreated and Electrochemically Treated Leachates through the Analysis of Early Seed Growth and Inductively Coupled Plasma-Optical Emission Spectroscopy Characterization
by Alfredo Martínez-Cruz and María Neftalí Rojas-Valencia
Horticulturae 2024, 10(1), 67; https://doi.org/10.3390/horticulturae10010067 - 09 Jan 2024
Viewed by 1107
Abstract
The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was [...] Read more.
The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was to investigate the phytotoxicity of the proposed treatment system on seed growth and examine possible relationships between phytotoxicity results and the characterization of leachates, effluents, soil, and radicles. Phytotoxicity tests were conducted on seeds of Lactuca sativa, Cucumis sativus, and Phaseolus vulgaris, using Inductively Coupled Plasma-Optical analysis. The evolution of organic matter was monitored by fractionating the chemical oxygen demand (COD) and humic substances. The biodegradability index increased from 0.094 in raw leachate to 0.26 and 0.48 with EC and EO, respectively. Removal rates of 82%, 86%, 99%, and 81% were achieved for COD, dissolved organic carbon, color, and ammoniacal nitrogen, respectively. The biodegradable COD increased from 26% in raw leachate to 39% in the EC process and 58% in the EO process effluent. The proposed treatment system successfully broke the aromatic structures of the humic substances present in the raw leachate, thereby increasing the content of biodegradable material. Phytotoxicity tests revealed that the proposed treatment system significantly reduced the phytotoxicity of the generated effluents. Full article
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14 pages, 2405 KiB  
Article
Effects of Supplemental Potassium on the Growth, Photosynthetic Characteristics, and Ion Content of Zoysia matrella under Salt Stress
by Ling Zhang, Qiaofeng Jiang, Junqin Zong, Hailin Guo, Jianxiu Liu and Jingbo Chen
Horticulturae 2024, 10(1), 31; https://doi.org/10.3390/horticulturae10010031 - 28 Dec 2023
Cited by 1 | Viewed by 808
Abstract
Potassium is crucial in plant metabolism processes, and sufficient potassium can improve plant tolerance to abiotic stress. We studied the effects of different KCl concentration treatments (0, 1, 5, 20 mM) on the biomass, photosynthetic characteristics, and ion content of Zoysia matrella under [...] Read more.
Potassium is crucial in plant metabolism processes, and sufficient potassium can improve plant tolerance to abiotic stress. We studied the effects of different KCl concentration treatments (0, 1, 5, 20 mM) on the biomass, photosynthetic characteristics, and ion content of Zoysia matrella under salt stress (NaCl 300 mM). The results showed that the plant dry weight, stomatal conductance, transpiration rate, photosynthesis rate, K+ content in plants, and K+/Na+ ratio in leaves of Zoysia matrella under NaCl stress were significantly lower than those under no NaCl conditions. The addition of K can promote an increase in plant dry weight and significantly improve the stomatal conductance, transpiration rate, and photosynthesis rate of plants. In addition, under salt stress, the addition of 20 mM KCl can significantly reduce the accumulation of Na+ in plants and promote the secretion of Na+ in leaves, thus improving the salt tolerance of Zoysia matrella. Full article
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19 pages, 6739 KiB  
Article
Effect of Osmolytes on Photoassembly of Functionally Active Mn4CaO5 Cluster in Mn-Depleted Photosystem II Preparations Isolated from Spinach Leaves
by Denis V. Yanykin, Dina V. Kazantseva and Andrey A. Khorobrykh
Horticulturae 2023, 9(12), 1339; https://doi.org/10.3390/horticulturae9121339 - 14 Dec 2023
Viewed by 784
Abstract
The effect of osmolytes (trehalose, sucrose, betaine, D-glucose and hydroxyectoine) on the photoassembly of the functionally active inorganic core of the water-oxidizing complex (Mn4CaO5 cluster) in Mn-depleted PSII preparations (apo-WOC-PSII) was investigated. It was revealed that the efficiency of the [...] Read more.
The effect of osmolytes (trehalose, sucrose, betaine, D-glucose and hydroxyectoine) on the photoassembly of the functionally active inorganic core of the water-oxidizing complex (Mn4CaO5 cluster) in Mn-depleted PSII preparations (apo-WOC-PSII) was investigated. It was revealed that the efficiency of the photoassembly of the Mn4CaO5 cluster was considerably (three times) increased in the presence of 1 M disaccharides (trehalose or sucrose) in contrast to other osmolytes. It was found that the osmolytes (especially trehalose or sucrose) improved the redox interaction of exogenous Mn2+ with apo-WOC-PSII, enhanced the protective effect of Mn2+ against the photoinhibition of apo-WOC-PSII, protected CaCl2-treated PSII preparations against thermoinactivation, and stabilized the water-oxidizing complex and electron transport from QA to QB in native PSII preparations during heat treatment. It is suggested that the ability of osmolytes to enhance the efficiency of the photoassembly of a Mn4CaO5 cluster depends on their effect on the following key processes: the redox interaction of Mn2+ with apo-WOC-PSII; the stability of apo-WOC-PSII to photoinhibition during the photoactivation procedure; and the stabilization of both the newly assembled functionally active Mn4CaO5 cluster and the electron transfer from QA to QB. Full article
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20 pages, 2244 KiB  
Article
Melatonin Enhanced Drought Stress Tolerance and Productivity of Pelargonium graveolens L. (Herit) by Regulating Physiological and Biochemical Responses
by Ragia M. Mazrou, Fahmy A. S. Hassan, Mohamed Magdy F. Mansour and Mohamed M. Moussa
Horticulturae 2023, 9(11), 1222; https://doi.org/10.3390/horticulturae9111222 - 11 Nov 2023
Cited by 1 | Viewed by 1040
Abstract
As a type of abiotic stress, drought limits plant growth and productivity. The increased demand for the valuable essential oil extracted from geranium (Pelargonium graveolens L.) is mainly regulated by plant growth, which is adversely affected by drought. Melatonin (MT) has been [...] Read more.
As a type of abiotic stress, drought limits plant growth and productivity. The increased demand for the valuable essential oil extracted from geranium (Pelargonium graveolens L.) is mainly regulated by plant growth, which is adversely affected by drought. Melatonin (MT) has been used to enhance plant growth under various abiotic stresses, although its impact on overcoming drought stress in aromatic plants, including geranium, has not yet been investigated. In the current investigation, MT at 100 µM was applied at 100% (well-watered) or 50% (drought stress) field capacity to verify the role of MT in geranium under drought stress. Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll content; however, MT alleviated these effects. The herb yield of the stressed plants was reduced by 59.91% compared to the unstressed plants, while this reduction was only 14.38% when MT was applied. In contrast, drought enhanced the essential oil percentage in geranium leaves. Despite the reduction in oil yield caused by drought, MT application mitigated this reduction and improved both oil yield and oil components. Moreover, the MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase, resulting in the alleviation of drought-induced oxidative damage. Consequently, MT reduced both hydrogen peroxide and malondialdehyde accumulation by 71.11 and 48.30%, respectively, under drought, thereby maintaining the cellular structures’ integrity. Overall, this is the first report that reveals the ability of MT application to improve geranium oil yield and resistance to drought by enhancing the antioxidant defense system. The results enrich awareness regarding the potential benefits of the external application of MT and its roles that can help researchers to improve aromatic plants’ performance and productivity under drought stress. Full article
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18 pages, 2186 KiB  
Article
The Effect of One-Year Seed Spaceflight Storage on Yield, Biochemical and Mineral Characteristics of Mature Leafy Vegetables Belonging to Brassicaceae, Apiaceae and Asteraceae Families
by Viktor Kharchenko, Nadezhda Golubkina, Liubov Skrypnik, Otilia Cristina Murariu, Lorenzo Vecchietti and Gianluca Caruso
Horticulturae 2023, 9(10), 1073; https://doi.org/10.3390/horticulturae9101073 - 25 Sep 2023
Cited by 2 | Viewed by 762
Abstract
Spaceflight is known to produce genetic changes in seeds, usually accelerating aging, though species and varietal differences have been poorly investigated. Comparisons were carried out in terms of yield, biochemical characteristics and mineral composition between mature plants grown from seeds subjected to a [...] Read more.
Spaceflight is known to produce genetic changes in seeds, usually accelerating aging, though species and varietal differences have been poorly investigated. Comparisons were carried out in terms of yield, biochemical characteristics and mineral composition between mature plants grown from seeds subjected to a one-year spaceflight, belonging to Brassicaceae (Brassica juncea and Eruca sativa), Apiaceae (Anethus graveolens, and Coriandrum sativum), and Asteraceae (Lactuca sativa, six cultivars) families, and non-treated control. Among the studied species, only Brassica juncea and Eruca sativa demonstrated a growth stimulation effect caused by seed spaceflight, while significant growth inhibition was recorded in Apiaceae plants and three cultivars of Lactuca sativa L. No differences in the total antioxidant activity (AOA), polyphenol and ascorbic acid content were detected between ‘space-treated’ and control plants. On the contrary, significant decrease in proline accumulation and increase in malonic dialdehyde and photosynthetic pigments levels were shown by Brassicaceae species. The effect of long-term seed spaceflight on the mineral composition of mature plants was reflected in the inhibition of accumulation of all 24 elements analyzed in Apiaceae plants, except for Se, whose concentration was higher in all ‘space-treated’ plants compared to the control. Spaceflight seed storage increased V levels in lettuce and decreased Na accumulation in all the investigated species. The results reveal species-dependent changes in the accumulation of macro-, micro- and toxic elements in Apiaceae, Brassicacea, and Asteraceae representatives due to spaceflight seed storage. The detected differences in plant elemental composition between ‘space’ treatment and control partly explain the corresponding yield gap and suggest a relationship between mineral status and adaptability. The highest beneficial effect of spaceflight seed storage on yield was recorded in Eruca sativa cultivar, Rusalochka. Full article
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20 pages, 4939 KiB  
Article
Plant Hormone Signals Mediate Melatonin Synthesis to Enhance Osmotic Stress Tolerance in Watermelon Cells
by Manwen Yan, Mingyan Li, Zhuoying Ding, Fei Qiao and Xuefei Jiang
Horticulturae 2023, 9(8), 927; https://doi.org/10.3390/horticulturae9080927 - 14 Aug 2023
Cited by 2 | Viewed by 995
Abstract
Melatonin, a multifunctional signaling molecule, has been shown to play a significant role in response to abiotic stress. Several species have been reported to unveil melatonin’s effect on osmotic stress; however, the signal transduction mechanism of phytohormone-mediated melatonin biosynthesis in plant species remains [...] Read more.
Melatonin, a multifunctional signaling molecule, has been shown to play a significant role in response to abiotic stress. Several species have been reported to unveil melatonin’s effect on osmotic stress; however, the signal transduction mechanism of phytohormone-mediated melatonin biosynthesis in plant species remains unclear. In this study, although plants can biosynthesize melatonin, the exogenous application of melatonin to watermelon cells can improve cell growth in response to osmotic stress by regulating the antioxidant machinery of cells. Regarding the melatonin synthesis pathway, ClOMT (ClASMT and ClCOMT) is a multi-gene family, and ClSNAT has two members. Both ClOMTs and ClSNATs harbor the cis-elements in their promoter regions responding to various hormones. Among abscisic acid (ABA), methyl jasmonate (MeJA), and salicylic acid (SA), ABA treatment observably upregulated the expression of ClOMTs and ClSNATs, and the accumulation of melatonin with ABA treatment reached a level comparable to that with osmotic stress by mannitol treatment. Furthermore, when hormone biosynthesis inhibitors were added to cells before osmotic stress, the expression of ClOMTs and ClSNATs, as well as melatonin accumulation, were significantly suppressed with the ABA biosynthesis inhibitor. This study demonstrated the crucial role of melatonin biosynthesis in response to osmotic stress via plant hormone signal transduction. It showed that ABA signaling plays a dominant role in melatonin synthesis under osmotic stress. Full article
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14 pages, 4040 KiB  
Article
Functional Verification of the Four Splice Variants from Ajania purpurea NST1 in Transgenic Tobacco
by Hai Wang, Xueying Hao, Wenxin Zhang, Yuning Guo, Xiang Zhao, Yanxi Li, Wenting He, Shiyi Cai and Xuebin Song
Horticulturae 2023, 9(8), 916; https://doi.org/10.3390/horticulturae9080916 - 10 Aug 2023
Viewed by 731
Abstract
Ajania purpurea is a small semi-shrub in the Asteraceae family. Its corolla is purplish red from the middle to the top, and its leaves and flowers are all fragrant. It can be introduced and cultivated as ornamental plants. In order to survive adversity, [...] Read more.
Ajania purpurea is a small semi-shrub in the Asteraceae family. Its corolla is purplish red from the middle to the top, and its leaves and flowers are all fragrant. It can be introduced and cultivated as ornamental plants. In order to survive adversity, plants actively regulate the expression of stress response genes and transcripts. Alternative splicing is a common phenomenon and an important regulation mode of eukaryotic gene transcription, which plays an important role in various biological processes. In this study, four splice variants of the NST1 gene were identified from A. purpurea, and the molecular mechanism of NST1 alternative splice variants involved in abiotic stress was explored through bioinformatics, transgenics and paraffin sectionalization. The analysis of amino acid sequences showed that ApNST1.1 had alternative 5′splicing, ApNST1.2 had alternative 3′splicing and ApNST1 had the two splicing types. The main conclusions from studying transgenic tobacco seedlings and adult seedlings under abiotic stress were as follows: ApNST1, ApNST1.1 and ApNST1.3 showed salt tolerance at seedling stage, especially ApNST1.3. At the mature seedling stage, the stem height of ApNST1.1 increased significantly, and ApNST1.1 showed obvious salt tolerance, while ApNST1.2 showed obvious cold resistance. Compared to Super35S::GFP, the xylem of ApNST1 thickened by 94 μm, and the cell wall thickened by 0.215 μm. These results are of great significance to the breeding and application of ApNST1 to select splice variants with more resistance to abiotic stress, and to future study in this area. At the same time, they provide a new direction for A. purpurea breeding, and increase the possibility of garden applications. Full article
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12 pages, 1743 KiB  
Article
Impact of Various Salinity Levels and Fusarium oxysporum as Stress Factors on the Morpho-Physiological and Yield Attributes of Onion
by Muhammad Zeeshan Mansha, Hafiz Muhammad Aatif, Kamran Ikram, Ch. Muhammad Shahid Hanif, Abdul Sattar, Rubab Iqbal, Qamar uz Zaman, Salem Mesfir Al-Qahtani, Nadi Awad Al-Harbi, Wael A. Omar and Mohamed F. M. Ibrahim
Horticulturae 2023, 9(7), 786; https://doi.org/10.3390/horticulturae9070786 - 10 Jul 2023
Cited by 1 | Viewed by 979
Abstract
The onion (Allium cepa L.) belongs to the family Alliaceae and has paramount importance among vegetable crops around the globe. Salinity stress and the soil-borne fungus Fusarium oxysporum f. sp. Cepa (FOC), which is the cause of basal rot, are potentially hazardous [...] Read more.
The onion (Allium cepa L.) belongs to the family Alliaceae and has paramount importance among vegetable crops around the globe. Salinity stress and the soil-borne fungus Fusarium oxysporum f. sp. Cepa (FOC), which is the cause of basal rot, are potentially hazardous factors related to the yield of onion crops. The present study was conducted in CRD using three replicates in in vitro conditions and in a greenhouse to investigate the impact of stress factors (salinity levels and FOC) (T1 = Negative control; T2 = Positive control (FOC); T3 = EC 2.5 dS m−1; T4 = EC 3.5 dS m−1; T5 = EC 4.5 dS m−1; T6 = EC 2.5 dS m−1 + FOC; T7 = EC 3.5 dS m−1 + FOC; and T8 = EC 4.5 dS m−1 + FOC) on the morphological, physiological, and yield parameters of onions. Fungal biomass, in the in vitro condition, increased at a salinity level of 2–8 dS m−1. In the greenhouse, the application of salinity levels, viz. 2.5, 3.5, and 4.5 dS m−1, and fungal pathogens exhibited a more severe impact on the severity of the disease, onion growth, and bulb compared to sole stress. Overall, the decreased levels of osmotic potential, total chlorophyll content, membrane stability index, and total protein were assessed in onion leaves, whereas total phenolics were enhanced in the mentioned stress conditions. Sugar contents were reduced due to the sole application of pathogens, whereas they were enhanced in the sole application of salinity stress and increased due to a combination of FOC and salinity level applications. Polyphenol oxidase (PPO) activity was not altered as a result of pathogen infection, while peroxidase (PO) and phenylalanine ammonia-lyase (PAL) contents were enhanced, and the activity of catalase (CAT) was reduced. Sole stress along with the combined application of salinity levels with fungal pathogens exhibited enhanced PO and PPO activity; in contrast, CAT and PAL activity decreased. In summary, onion crop cultivation in saline soil conditions increases the disease’s severity, which is caused by FOC. Furthermore, it is crucial to carry out field trials while considering these outcomes in order to support a strong strategy for reducing the tested stresses within a wider range of environmental conditions. Full article
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15 pages, 1818 KiB  
Article
Lettuce in Monoculture or in Intercropping with Tomato Changes the Antioxidant Enzyme Activities, Nutrients and Growth of Lettuce
by Tatiana P. L. Cunha-Chiamolera, Arthur Bernardes Cecílio Filho, Durvalina M. M. Santos, Fernando M. Chiamolera, Ramón G. Guevara-González, Silvana Nicola and Miguel Urrestarazu
Horticulturae 2023, 9(7), 783; https://doi.org/10.3390/horticulturae9070783 - 10 Jul 2023
Cited by 1 | Viewed by 1490
Abstract
Intercropping systems are a widely used agricultural practice by smallholder farmers to enhance food security and to use natural resources more efficiently. The objective of this study was to evaluate two lettuce cvs under an intercropping system. Enzymatic growth, yield and economic benefit [...] Read more.
Intercropping systems are a widely used agricultural practice by smallholder farmers to enhance food security and to use natural resources more efficiently. The objective of this study was to evaluate two lettuce cvs under an intercropping system. Enzymatic growth, yield and economic benefit were evaluated. The experiment was carried out from August to February in Jaboticabal (Brazil) using tomato plants as a main crop and Lucy Brown and Vanda cvs of lettuce as secondary crops. The catalase, superoxide dismutase and peroxidase activity of lettuce plants was analyzed. Mineral nutrient content, growth, yield parameters and commercial economic benefit were measured. Significant differences in stress and activity enzymatic indicators were found versus cultivars of lettuce. The loss of abiotic factors such as radiation or its effect on enzymatic stress indicators was greater than its effect on yield. Yield loss in the intercropping systems was different for each cultivar system, with cv Lucy Brown showing greater yield loss than cv Vanda. Economic benefit was only found for the Vanda lettuce cv. Although the benefits of intercropping have been demonstrated as very appropriate cultural management, the choice of cultivars involved might be the determining factor for the agronomic success of the system. Full article
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