Special Issue "Biostimulants as Physiological Modulators of Crop Performance and Product Quality"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Horticultural and Floricultural Crops".

Deadline for manuscript submissions: closed (31 May 2022) | Viewed by 29493

Special Issue Editors

Prof. Dr. Youssef Rouphael
E-Mail Website
Guest Editor
Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Interests: greenhouse crops; vegetables production; hydroponics and aquaponics; plant nutrition; microgreens; sprouts; edible flowers; functional foods, grafting; microbial and non-microbial biostimulants; biofortification; vegetable quality related to preharvest factors; LED; urban agriculture; organic farming
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Giuseppe Colla
E-Mail Website
Guest Editor
Department of Agriculture and Forest Sciences, University of Tuscia, 01100 Viterbo, Italy
Interests: microgreens, sprouts; functional food; crop production; plant nutrition; fertilizers; organic farming; organic agriculture; nutrient management; biofertilizers; vegetable production; fruit quality; fertigation; hydroponics; vegetable crops; biofortification
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The world’s horticultural systems face a great balancing act between two needs, on one side to raise the supply of food produced on the available farmland, since the global population will increase to more than 10 billion by 2050, and on the other side to reduce agriculture’s impact on the environment and human health. Meeting these two targets presents a major sustainability challenge to scientists and producers, which might be fostered by using natural products known as plant biostimulants. A plant biostimulant has recently been defined in the regulations (EU) 2019/1009 of the European Parliament and Council (EC) as an “EU fertilising product able to stimulate plant nutrition processes independently of the product’s nutrient content with the sole aim of improving one or more of the following characteristics of the plant or the plant rhizosphere: 1) nutrient use efficiency, 2) tolerance to abiotic stress, 3) quality traits, or 4) availability of confined nutrients in the soil or rhizosphere”. Plant biostimulants, by this definition, include several substances with bioactive properties: seaweed and plant extracts, humic and fulvic acids, protein hydrolysates and silicon, as well as some-plant growth-promoting microorganisms: mycorrhizal fungi and plant-growth-promoting rhizobacteria.

Following the huge success of the first Special Issue, “Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications”, we have decided to launch a second Special Issue entitled “Biostimulants as Physiological Modulators of Crop Performance and Product Quality”. This Special Issue invites original research, technology report, methods, opinion, perspectives, and invited reviews and mini reviews dissecting the biostimulation action of these natural compounds and substances and beneficial microorganisms on crops grown under optimal and suboptimal growing conditions (e.g., salinity, drought, nutrient deficiency and toxicity, heavy metal contaminations, waterlogging, and adverse soil pH conditions). Also of interest are potential contributions dealing with the effect as well as the molecular and physiological mechanisms of plant biostimulants on nutrient efficiency, product quality, post-harvest, and the modulation of the microbial population quantitatively and qualitatively. In addition, identification and understanding of the optimal method, time, rate of application, and phenological stage for improving plant performance and resilience to stress as well as the best plant species/cultivar × environment × management practices combinations will be considered within the general scope of the Special Issue. We strongly believe that this compilation of high-standard scientific papers on principles and practices of plant biostimulants will foster knowledge transfer among scientific communities, industries, and agronomists and will enable a better understanding of the mode of action and application procedure of biostimulants in different cropping systems.

Prof. Youssef Rouphael
Prof. Giuseppe Colla
Guest Editors

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Keywords

  • humic acids
  • microbial inoculants
  • PGPR
  • nitrogen-fixing bacteria
  • mycorrhizal fungi
  • microbiome
  • protein hydrolysate
  • silicon
  • physiological and molecular mechanisms
  • seaweed extracts
  • microalgae
  • functional biostimulants
  • agronomical and horticultural crops
  • abiotic stressors
  • NUE
  • post-harvest

Published Papers (25 papers)

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Research

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Communication
Effect of Herbicide and Biostimulants on Production and Economic Results of Edible Potato
Agronomy 2022, 12(6), 1409; https://doi.org/10.3390/agronomy12061409 - 11 Jun 2022
Cited by 1 | Viewed by 502
Abstract
In modern agriculture, preparations qualified as biostimulants are used alongside pesticides. They influence the development of plants and enable a yield-forming effect. An important feature of these preparations is that they are safe for the environment. They can be treated as substitutes for [...] Read more.
In modern agriculture, preparations qualified as biostimulants are used alongside pesticides. They influence the development of plants and enable a yield-forming effect. An important feature of these preparations is that they are safe for the environment. They can be treated as substitutes for plant protection agents, which is especially important in the era of implementation of the European Green Deal, ordering the reduction of chemicalization of agriculture. The purpose of this paper was to compare the production and economic results of five methods of plantation care in Solanum tuberosum cultivation: on the first object (control), mechanical cultivation was used, and on the second, object the herbicide Avatar 293 ZC (1.5 dm3·ha−1), on object three, the herbicide Avatar 293 ZC (1.5 dm3·ha−1) and the biostimulant PlonoStart (2.0 dm3·ha−1), on object four, the herbicide Avatar 293 ZC (1.5 dm3·ha−1) and biostimulant Aminoplant (1.5 dm3·ha−1), and on object five, the herbicide Avatar 293 ZC (1.5 dm3·ha−1) and biostimulant Agro-Sorb Folium (4.0 dm3·ha−1). The research was conducted from 2018 to 2020 at the Agricultural Experimental Station in Zawady, central-eastern Poland. The results were analyzed, on average, for two Polish edible potato cultivars (Malaga and Oberon), and three years of study (2018–2020) were taken into consideration. The experiment was established as a two-factor experiment in three replicates on light soil in a spit-plot arrangement. A beneficial effect of herbicides and biostimulants on the yield and profitability of edible potato production was observed. An average increase of 33.2% in marketable yield was obtained. The gross margin increased by an average of 49.3%. The highest total yield, as compared to the control object, was obtained from object 5, where the herbicide Avatar 293 ZC with biostimulant Agro-Sorb Folium was applied, such as the greatest economic effect was achieved also in object no. 5. Application of this biostimulant was most beneficial. Full article
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Article
Foliar Application of GA3 Stimulates Seed Production in Cauliflower
Agronomy 2022, 12(6), 1394; https://doi.org/10.3390/agronomy12061394 - 10 Jun 2022
Cited by 3 | Viewed by 553
Abstract
This study aimed to evaluate the influence of gibberellic acid on both concentration and time of application on the seed production ability of BU cauliflower-1. The experiment was conducted to determine seed production ability at five concentrations of GA3: G0 [...] Read more.
This study aimed to evaluate the influence of gibberellic acid on both concentration and time of application on the seed production ability of BU cauliflower-1. The experiment was conducted to determine seed production ability at five concentrations of GA3: G0 = Control, G1 = 100 ppm, G2 = 200 ppm, G3 = 300 ppm, G4 = 400 ppm, along with four application times at different growth stages including T1 = Foliar application at 3 weeks after planting, T2 = Foliar application at 4 weeks after planting, T3 = Foliar application at 5 weeks after planting and T4 = Foliar application at 6 weeks after planting. Results revealed that 200 ppm GA3 gave the highest plant height (44.05 cm), the number of primary (10.88) and secondary flowering branches (31.33), stalk length (79.53 cm), seeded pods per plant (465), pod length (4.975 cm), seeds per pod (10.87), seed yield per plant (16.16 g), seed yield (0.24 ton/ha), and weight of thousand seeds (4.826 g) with the earliest curd (51.02 days) and flower initiation (84.17 days). It also gave the highest net return (Tk. 4.7 lakh/ha) and benefit-cost ratio (4.34). GA3 application at 3 weeks after transplanting had the highest numbers of primary and secondary flowering branches, pods, seeded pods, and seed yield per plant. The treatment combination of G2T1 gave the earliest curd initiation (49.60 days), the highest number of secondary flowering branches (34.87), seed yield per plant (22.75 g), and seed yield (0.27 ton/h). In contrast, the G2T2 treatment resulted in the earliest flower initiation (81.77 days) with the highest pod length (5.20 cm), the number of pods per plant (707), and seeded pods per plant (507), and seeds per pod (11.30). Hence, 200 ppm GA3 applied three weeks after transplanting could be used as the best combination for cauliflower seed production with the highest net return and benefit-cost ratio. Enhancing seed yield is our ultimate goal; hence, we suggest 200 ppm GA3 three weeks after transplanting for increased cauliflower seed production with the highest return and benefit-cost ratio in the study area. As we performed the study in a particular location, we recommend multilocation trials in different agro-ecological regions to study the genotype–environment interaction for final confirmation of the results. Full article
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Article
Heat-Stress-Mitigating Effects of a Protein-Hydrolysate-Based Biostimulant Are Linked to Changes in Protease, DHN, and HSP Gene Expression in Maize
Agronomy 2022, 12(5), 1127; https://doi.org/10.3390/agronomy12051127 - 07 May 2022
Viewed by 457
Abstract
The growth-promoting and heat-mitigating effects of a commercially available protein-hydrolysate-based biostimulant, Kaishi, during the early vegetative stage was investigated by applying it as a foliar spray on soil-grown maize plants or in the nutrient solution of hydroponically grown plants. At 10−3 dilution, [...] Read more.
The growth-promoting and heat-mitigating effects of a commercially available protein-hydrolysate-based biostimulant, Kaishi, during the early vegetative stage was investigated by applying it as a foliar spray on soil-grown maize plants or in the nutrient solution of hydroponically grown plants. At 10−3 dilution, the biostimulant inhibited germination and delayed the growth progress, while at 10−6–10−12 dilutions, it promoted shoot and root growth. Heat stress caused biomass reduction, decreased leaf pigment content and the chlorophyll a/chlorophyll b (chl a/b) ratio, caused starch depletion, and increased lipid peroxidation. Kaishi priming resulted in the substantial mitigation of negative stress effects, maintaining growth, stabilizing pigment content and the chl a/b ratio, restoring the leaf starch content, lowering the malondialdehyde (MDA) level, and significantly increasing the free proline content. The expression profiles of a set of genes coding for heat shock proteins (HSPs), dehydrins (DHNs), and proteases were analysed using qRT-PCR after heat stress exposure. The biostimulant-treated plants had higher transcript levels of certain HSPs, DHNs, and protease-coding genes, which remained stable or increased after the applied stress. The results demonstrate that very low concentrations of the biostimulant exerted stress-mitigating effects that could be linked to organ-specific changes in the gene expression of certain stress-inducible proteins. Full article
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Article
The Effect of an Engineered Biostimulant Derived from Ascophyllum nodosum on Grass Yield under a Reduced Nitrogen Regime in an Agronomic Setting
Agronomy 2022, 12(2), 463; https://doi.org/10.3390/agronomy12020463 - 13 Feb 2022
Cited by 1 | Viewed by 1053
Abstract
Nitrogen (N) is the most important macronutrient used in modern agricultural systems to enhance crop yields; however, a significant amount of applied N is not taken up by the crop and is lost to the environment. Improving the nitrogen use efficiency (NUE) of [...] Read more.
Nitrogen (N) is the most important macronutrient used in modern agricultural systems to enhance crop yields; however, a significant amount of applied N is not taken up by the crop and is lost to the environment. Improving the nitrogen use efficiency (NUE) of crops can curb these environmental losses while concurrently delivering economic gains. Plant biostimulants have potential to improve NUE in agronomic settings. In this research, a granular N-containing fertilizer coated with the biostimulant PSI-362, an extract from the brown seaweed Ascophyllum nodosum, was applied to grass managed under different production systems to assess its impact on NUE. The role of soil type, pH, phosphorus (P) and potassium (K) on the efficacy of the biostimulant in improving NUE was assessed using lysimeters filled with six different soils. A significant increase in grass yield (29%) was found with PSI-362 addition at a 75% N rate over the 75% N control (8478 kg of dry matter (DM) ha−1 vs. 6772 kg of DM ha−1) over two years of trials under a simulated grazing platform of six rotations. The NUE increased to 96.6% for the PSI-362-treated grass compared to 82.8% for controls. Field-based evaluations demonstrated no decrease in yield and quality from harvested and grazed grass treated with the biostimulant when the N rate was reduced by 20 to 25%. Based on these results, the application of PSI-362 allows a reduction in nitrogen input by up to 25% without losses of grass yield or quality. Full article
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Article
Combined Biostimulant Applications of Trichoderma spp. with Fatty Acid Mixtures Improve Biocontrol Activity, Horticultural Crop Yield and Nutritional Quality
Agronomy 2022, 12(2), 275; https://doi.org/10.3390/agronomy12020275 - 21 Jan 2022
Cited by 1 | Viewed by 1095
Abstract
The growing demand for safer foods reflects the public perception of the adverse consequences of chemicals used in agriculture. This research aimed at developing new biological formulations based on the combination of small microbial consortia containing two Trichoderma spp., with a medium–long chain [...] Read more.
The growing demand for safer foods reflects the public perception of the adverse consequences of chemicals used in agriculture. This research aimed at developing new biological formulations based on the combination of small microbial consortia containing two Trichoderma spp., with a medium–long chain fatty acids mixture (FAm). The bioactivity of these formulations was investigated on different vegetable crops in terms of biocontrol, growth promotion, yield and quality improvements. FAm application reduced Botrytis cinerea necrosis by up to 90% compared to the infected control plants and some of the assayed Trichoderma spp. + FAm combinations contained Rhizoctonia disease, reaching more than 90% reduction of tomato and lettuce plant mortality. An increasing yield, ranging to 25 and 90%, was recorded on treated tomato, lettuce and kohlrabi compared to untreated plants. A significant enrichment in carotenoids (+60%) and glucosinolates (+39%) was measured on biotreated plants compared to controls. Untargeted LC-MS analysis revealed a higher content of tomatine and dehydro-phytosphingosine, glycoalkaloids involved in defense responses, in Trichoderma spp. + FAm combination-treated plants. The combined biostimulant applications of Trichoderma spp. with FAm were able to improve the performances of different horticultural plant species, producing a premium quality marketable vegetable with higher antioxidant content. Full article
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Article
The Effect of Titanium Organic Complex on Pollination Process and Fruit Development of Apple cv. Topaz
Agronomy 2021, 11(12), 2591; https://doi.org/10.3390/agronomy11122591 - 20 Dec 2021
Viewed by 948
Abstract
Optimal weather conditions are necessary for the proper course of the flowering process and high activity of pollinators, which is the most important factor affecting pollination. Because weather conditions do not always favour effective pollination and because pollinators’ activities are decreasing, the application [...] Read more.
Optimal weather conditions are necessary for the proper course of the flowering process and high activity of pollinators, which is the most important factor affecting pollination. Because weather conditions do not always favour effective pollination and because pollinators’ activities are decreasing, the application of compound stimulating pollination and fertilization may be a good perspective for increasing yield. Titanium is considered a beneficial element for plants. Preliminary studies have indicated the positive effect of titanium organic complex on pollen adhesion to the stigma and pollen germination on the stigma of tomato and cucumber. Therefore, a 2-year experiment was designed to determine the effect of titanium organic complex application on the pollination process and fruit development of apple cv. Topaz (Malus domestica Borkh.) The experiment demonstrated the positive effect of titanium organic complex on fertilization of ovules because of effective pollination, seed setting, and fruit development of apple. Application of titanium organic complex improved pollen adhesion to the stigma and pollen germination on the stigma. In addition, titanium organic complex increased the number of pollen tubes growing through the pistil style, which resulted in fertilization that was more effective, as confirmed by the higher number of seeds set in fruits. Higher numbers of seeds set in fruits positively affected their weight and size. Therefore, fruit harvested from trees to which titanium organic complex was applied were characterized by greater weight, length, and diameter compared to fruits obtained from the trees to which titanium organic complex was not applied. Full article
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Article
Effects of Nitrogen, Azoxystrobin and a Biostimulant Based on Brown Algae and Yeast on Wild Rocket Features at Harvest and During Storage
Agronomy 2021, 11(11), 2326; https://doi.org/10.3390/agronomy11112326 - 17 Nov 2021
Viewed by 634
Abstract
Recently, the use of biostimulant substances of different origins has been affirmed. They act differently on the physiological processes of the plant, helping to improve its productive response and resistance to biotic and abiotic stress. Therefore, the response of the wild rocket to [...] Read more.
Recently, the use of biostimulant substances of different origins has been affirmed. They act differently on the physiological processes of the plant, helping to improve its productive response and resistance to biotic and abiotic stress. Therefore, the response of the wild rocket to two substances known to have biostimulating activity (Azoxystrobin, and a fluid extract of brown algae and yeast), was evaluated. Two experimental trials (Exp 1 and Exp 2) were carried out in the greenhouse. The collected product, in addition to being evaluated from a qualitative point of view, was used for evaluation of shelf life. Exp 1 involved the comparison of two N levels with two Azoxystrobin levels (treated–Azo+, and untreated control). Exp 2 involved the comparison of two N levels, and two biostimulating substances based on Azoxystrobin (Azo+) and on fluid extracts of yeast and brown algae (YBA+), in addition to untreated control. A split-plot experimental design with three replications was used. Azo+ increased marketable yield of wild rocket by 16.8% and enhanced some qualitative features at harvest as the increase in chlorophyll (+17.8%) and carotenoids (+13.5%), and decrease in nitrates (−10.6%), regardless of the nitrogen level. Furthermore, Azo+ increased the shelf life (+2.5 days) of wild rocket stored at 3.5 °C. In particular, Azo+ slowed the loss of chlorophyll (yellowing) and the worsening of odor and visual appearance. As Azoxystrobin is a fungicide effective for the control of some diseases of wild rocket, its use should be promoted as it would offer not only the benefit of disease control but also improved production and shelf life. YBA+ caused an increase in the chlorophyll content (+12.5%) at harvest of wild rocket, but reduced its antioxidant activity (−40%). YBA+ did not cause substantial variations in shelf life with the exception of a slowdown in the degradation of carotenoids. Further research is desirable to evaluate other variables such as the dose and time of application. Full article
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Article
Exogenous Application of Biostimulants and Synthetic Growth Promoters Improved the Productivity and Grain Quality of Quinoa Linked with Enhanced Photosynthetic Pigments and Metabolomics
Agronomy 2021, 11(11), 2302; https://doi.org/10.3390/agronomy11112302 - 14 Nov 2021
Cited by 6 | Viewed by 821
Abstract
Modern agriculture is mainly concerned with maximum resource use efficiency linked with greater productivity to feed the growing global population. The exogenous application of biostimulants is considered a sustainable approach to improve the growth and productivity of field crops. The present study was [...] Read more.
Modern agriculture is mainly concerned with maximum resource use efficiency linked with greater productivity to feed the growing global population. The exogenous application of biostimulants is considered a sustainable approach to improve the growth and productivity of field crops. The present study was carried out to explore the comparative impact of biostimulants and synthetic compounds on quinoa crop (cultivar UAF-Q7), as it has gained significant popularity among agricultural scientists and farmers throughout the world, due to its high nutritional profile. A two-year field experiment was carried out at the Research Area of Directorate of Farms, University of Agriculture, Faisalabad, Pakistan. Application of moringa leaf extract (MLE) produced the maximum total chlorophyll (5.11 mg g−1) and carotenoids (1.2 mg g−1), compared with the control. Antioxidants’ activities and gas exchange attributes were also recorded as the highest following MLE application. Mineral elements in root and in shoot were found highest in response to MLE application. Similarly, application of MLE significantly improved the growth and yield attributes of quinoa. Mineral elements of grain (Mg, Zn and Fe) were also significantly enhanced. MLE was found to be more responsive in improving the growth and quality compared with synthetic compounds. Full article
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Article
Biostimulant Effects of Cerium on Seed Germination and Initial Growth of Tomato Seedlings
Agronomy 2021, 11(8), 1525; https://doi.org/10.3390/agronomy11081525 - 30 Jul 2021
Cited by 4 | Viewed by 840
Abstract
The rare earth element (REE) cerium (Ce) can act as a biostimulant in diverse crop plants. The effects of 0, 5, 10, and 15 µM Ce (supplied as CeCl3 7H2O) on seed germination and the initial growth of tomato ( [...] Read more.
The rare earth element (REE) cerium (Ce) can act as a biostimulant in diverse crop plants. The effects of 0, 5, 10, and 15 µM Ce (supplied as CeCl3 7H2O) on seed germination and the initial growth of tomato (Solanum lycopersicum L.) cv. Vengador were evaluated. After a 12 h imbibition, the weight of the seeds treated with 15 µM Ce was 37.5% greater than that observed in the control. The germination index of the seeds treated with 5 µM Ce was greater than 100% (101.93%), though when applying 10 µM Ce this index was 17.53% lower than the control seeds. Nevertheless, Ce treatments did not significantly affect the coefficient of velocity of germination, relative seed germination, germination index, radicle length, dry biomass, or relative growth. Interestingly, shoot length increased significantly in the treatments with 5, 10, and 15 µM Ce. This tendency was also observed in the dry biomass weight and relative growth of the shoots. Hence, Ce has a stimulating effect on germination and initial growth in tomato cv. Vengador shoots. In particular, there was a priming effect of Ce on seeds, reflected in a higher weight gain in Ce-treated seeds, which indicated greater water absorption. Therefore, Ce can be an alternative to accelerate the production time of tomato seedlings in seedbeds. Full article
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Article
The Modulation of Auxin-Responsive Genes, Phytohormone Profile, and Metabolomic Signature in Leaves of Tomato Cuttings Is Specifically Modulated by Different Protein Hydrolysates
Agronomy 2021, 11(8), 1524; https://doi.org/10.3390/agronomy11081524 - 30 Jul 2021
Cited by 1 | Viewed by 741
Abstract
Protein hydrolysates (PHs) are employed in agriculture to increase the sustainability of farming systems, with positive results on crop productivity and response against environmental stressors. Nevertheless, the molecular mechanism(s) triggered by their specific activity is not clearly understood. In this work, five PHs [...] Read more.
Protein hydrolysates (PHs) are employed in agriculture to increase the sustainability of farming systems, with positive results on crop productivity and response against environmental stressors. Nevertheless, the molecular mechanism(s) triggered by their specific activity is not clearly understood. In this work, five PHs obtained by enzymatic hydrolysis of different vegetal protein sources were tested for their root-promoting activity on tomato cuttings. All the treatments improved both root length and number when compared to negative controls. Distinctive metabolomic signatures were highlighted in response to treatments, indicating the triggering of different molecular processes in leaf tissues of tomato cuttings. PHs differentially modulated the biosynthesis of plant stress-protectants, such as alkaloids and phenylpropanoids. Moreover, metabolites involved in phytohormone biosynthesis were significantly impacted. In this context, a clear modulation of several compounds related to auxin homeostasis was observed. In addition, the differential modulation of SlIAA2 and SlIAA9 genes, which are involved in the IAA signalling pathway, might further suggest the auxin-like activity elicited by the PHs tested. Here we provide evidence that PHs can impact plant molecular level, positively affecting root development, most likely by affecting the signalling cascades activated in leaf tissues. The biostimulant activity was sustained by PH-specific response at the molecular level, likely ascribable to their heterogeneous botanical origins. In fact, our findings did not point out a clear universal response to PHs, and specific effects are to be investigated. Full article
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Article
Foliar and Root Applications of Vegetal-Derived Protein Hydrolysates Differentially Enhance the Yield and Qualitative Attributes of Two Lettuce Cultivars Grown in Floating System
Agronomy 2021, 11(6), 1194; https://doi.org/10.3390/agronomy11061194 - 11 Jun 2021
Cited by 12 | Viewed by 1136
Abstract
Lettuce (Lactuca sativa L.) is a leafy vegetable cultivated widely for its fast and year-round production and its beneficial phytochemical content, which may be boosted further by plant biostimulants that are considered eco-sustainable means for enhancing horticultural crop production. A greenhouse experiment [...] Read more.
Lettuce (Lactuca sativa L.) is a leafy vegetable cultivated widely for its fast and year-round production and its beneficial phytochemical content, which may be boosted further by plant biostimulants that are considered eco-sustainable means for enhancing horticultural crop production. A greenhouse experiment was carried out to evaluate the yield and qualitative parameters of two differently pigmented lettuce cultivars grown in a floating raft system either untreated or treated (leaf, root or leaf/root application) with vegetal protein hydrolysates (PHs). For foliar application (F), lettuce plants were sprayed at a dose of 3 mL L−1, whereas for root application, 0.15 (T1) or 0.3 (T2) mL L−1 was applied to the nutrient solution alone or in combination with foliar spray (T1 + F and T2 + F) with the same foliar concentration. Bio-morphometric and production data were collected after harvest. Physiological and plant nutrition assays included leaf gas exchange, leaf fluorescence, SPAD index, mineral content, carotenoids, total phenols, total ascorbic acid content and antioxidant activities. Cultivar-specific reactions to biostimulant application were noted: whilst the green pigmented cultivar thrived under nutrient solution applications and recorded higher yield by 82.7% (T1) or (T1 + F) and 71.7% (T2), the red cultivar thrived under combined treatments, yielding 55.4% (T2 + F) higher than control and providing the most concentrated phytochemical content. These latter treatments also engendered the highest SPAD index, Fv/Fm ratio, CO2 assimilation, stomatal conductance and transpiration. In addition, the T2 + F treatment boosted ‘Canasta’ hydrophilic antioxidant activity (21.9%) and total ascorbic acid (5.6-fold). Nutrient solution treatments alone proved advantageous when compared to foliar treatments, while mixed treatments proved genotype-specific. New research on genotype specificity of biostimulant effects is warranted for future use, in order to rationalize biostimulant application modes and dosages. Full article
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Article
VNT4, a Derived Formulation of Glutacetine® Biostimulant, Improved Yield and N-Related Traits of Bread Wheat When Mixed with Urea-Ammonium-Nitrate Solution
Agronomy 2021, 11(5), 1013; https://doi.org/10.3390/agronomy11051013 - 20 May 2021
Viewed by 1269
Abstract
Optimizing nitrogen use efficiency (NUE) could mitigate the adverse effects of nitrogen (N) fertilizers by limiting their environmental risks and raising agronomic performance. We studied the effects of VNT4, a derived formulation of Glutacetine® biostimulant, mixed with urea-ammonium-nitrate solution (UAN) on the [...] Read more.
Optimizing nitrogen use efficiency (NUE) could mitigate the adverse effects of nitrogen (N) fertilizers by limiting their environmental risks and raising agronomic performance. We studied the effects of VNT4, a derived formulation of Glutacetine® biostimulant, mixed with urea-ammonium-nitrate solution (UAN) on the growth, N-related traits and agronomic performance of winter wheat (Triticum aestivum L.). The experiment was performed under six contrasting field conditions over two years in Normandy (France), including a site where 15N labelling was undertaken. Taking into account all the sites, we report that VNT4 significantly improved grain yield (+359 kg ha−1), total grain N and NUE. VNT4 application improved growth during tillering and stem elongation (+10.7%), and N and 15N uptake between tillering and maturity (+7.3% N and +16.9% 15N) leading to a higher N accumulation at maturity (+9.3% N). This N mainly originated from fertilizer (+19.4% 15N) and was assimilated after the flag leaf stage in particular (+47.6% 15N). These effects could be related to maintenance of physiological functions of flag leaves as suggested by the enhancement of their nutrient status (especially S, Zn and Mo). The adoption of VNT4 as a UAN additive is an efficient agronomic practice to enhance wheat productivity under an oceanic temperate climate. Full article
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Article
Transcriptomic and Metabolomic Studies Reveal Mechanisms of Effects of CPPU-Mediated Fruit-Setting on Attenuating Volatile Attributes of Melon Fruit
Agronomy 2021, 11(5), 1007; https://doi.org/10.3390/agronomy11051007 - 19 May 2021
Viewed by 976
Abstract
N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), a synthetic cytokinin-active compound, is widely applied to induce parthenocarpic fruit set and enhance melon fruit enlargement (Cucumis melo L.). CPPU may also influence fruit quality; however, the mechanisms through which this occurs remain unknown. We investigated the differences in [...] Read more.
N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), a synthetic cytokinin-active compound, is widely applied to induce parthenocarpic fruit set and enhance melon fruit enlargement (Cucumis melo L.). CPPU may also influence fruit quality; however, the mechanisms through which this occurs remain unknown. We investigated the differences in volatile emissions between parthenocarpic fruit set by CPPU (C) and seeded fruit set by artificial pollination (P). Gas chromatography–mass spectrometry (GC–MS) analysis revealed that six volatile organic compounds (VOCs) emitted by the P-group fruits were not detected in C-group fruits. The relative abundances of another 14 VOCs emitted by the CPPU-treated fruits were less than those in the P-group fruits. RNA sequencing analysis indicated that a total of 1027, 994, and 743 differentially expressed genes (DEGs) were detected in the C20 (treatment with 20 mg·L–1 CPPU) vs. P, P-C20 (pollination followed by 20 mg·L−1 CPPU treatment) vs. P, and P-C20 vs. C20 treatments, respectively. Compared with the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, the DEGs related to fatty acid degradation and metabolism, which contribute to volatile production, were enriched. In particular, DEGs such as carotenoid cleavage dioxygenase (CCD)-, lipoxygenase (LOX)-, alcohol dehydrogenase (ADH)-, and alcohol acyltransferase (ATT)-related genes were closely related to the formation of volatiles. In summary, our study provides a metabolic and transcriptomic atlas, reveals the impact of CPPU on VOCs, and enhances our understanding of the mechanisms of CPPU that contribute towards generally reducing the quality of melon fruit. Full article
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Article
Biostimulant Application Improves Yield Parameters and Accentuates Fruit Color of Annurca Apples
Agronomy 2021, 11(4), 715; https://doi.org/10.3390/agronomy11040715 - 09 Apr 2021
Viewed by 946
Abstract
The Annurca apple is a typical fruit from Southern Italy that is notable for its high firmness and characteristic flavor, and presents positive effects on human health. The aim of the present study was to improve the agronomic characteristics of Annurca trees and [...] Read more.
The Annurca apple is a typical fruit from Southern Italy that is notable for its high firmness and characteristic flavor, and presents positive effects on human health. The aim of the present study was to improve the agronomic characteristics of Annurca trees and the quality of their fruits by the use of plant biostimulants. We performed the study with three biostimulants (protein hydrolysates, seaweed extracts, and microalgae) to determine their effects on trees and fruits at harvest and during fridge conservation. The measurements in the field concerned the production per plant, the number of fruits, the diameter and fruit weight, the diameter of trunk, the weight of pruning, the first harvest %, and yield efficiency (plant prod./TCSA) for both growing seasons 2018–2019. The analyzed fruit parameters at harvest and during the fridge conservation were: flesh firmness, epicarp color, total soluble solids, pH, and titratable acidity. The results showed positive effects of the biostimulants on the production and the color parameters, especially with microalgae enhancing fruit redness (5-fold) and color index (8.5-fold). In particular, protein hydrolysates and microalgae increased the production (10.4%), diameter of the fruits (7.0%), the first harvest percentage (37.8%), and yield efficiency (6.9%). The tested plant biostimulants showed no significant effect on the measured qualitative parameters. This study represents the first detailed research on the use of different types of biostimulants on Annurca trees and their impact on the quality of its fruits from harvest to storage, and may present a sustainable alternative for the “melaio” processes. Full article
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Article
Yield Enhancement of Biostimulants, Vitamin B12, and CoQ10 Compared to Inorganic Fertilizer in Radish
Agronomy 2021, 11(4), 697; https://doi.org/10.3390/agronomy11040697 - 07 Apr 2021
Cited by 4 | Viewed by 1361
Abstract
Two pot experiments were conducted to evaluate the response of radish crops against different plant growth regulators, biostimulants, and leaf extracts at Yale University, USA. The first experiment examined the marginal effect of vitamin B12 when added to the Berlyn Laboratory’s proprietary biostimulant [...] Read more.
Two pot experiments were conducted to evaluate the response of radish crops against different plant growth regulators, biostimulants, and leaf extracts at Yale University, USA. The first experiment examined the marginal effect of vitamin B12 when added to the Berlyn Laboratory’s proprietary biostimulant formula (GPB Core). Increasing concentrations of vitamin B12 were added, as investigated in groups SL (0 mg/L), SB1 (0.5 mg/L), SB2 (1.0 mg/L), and SB3 (1.5 mg/L). The addition of vitamin B12 conferred no significant incremental benefit over the GPB Core. However, the GPB Core formula (SL) increased fresh shoot biomass by 172.9%, dry shoot biomass by 136.4%, fresh root biomass by 64.7%, and dry root biomass by 29.1% over plant treated with inorganic fertilizer alone (p < 0.01). The second experiment examined the combined marginal effect of vitamin B12 and coenzyme Q10 (CoQ10) when added to the GPB Core. The three experimental groups included the GPB Core plus inorganic fertilizer (S+); GPB Core, vitamin B12, CoQ10, and inorganic fertilizer (SBQ+); and GPB Core, vitamin B12, CoQ10, and no inorganic fertilizer (SBQ0). SBQ0 outperformed the inorganic fertilizer control in fresh shoot, dry shoot, fresh root, and dry root biomass by 190.3%, 127.1%, 128.5%, and 41.3%, respectively (p < 0.01), indicating that inorganic fertilizer can be replaced by biostimulants while simultaneously increasing yield. Additionally, the differences between SBQ+ and SBQ0 in the biomass metrics were statistically insignificant, indicating that in the presence of biostimulants, inorganic fertilizers confer a slight marginal benefit. There was no evidence, however, that the addition of CoQ10 and vitamin B12 conferred benefits over S+. Overall, the application of biostimulants statistically significantly improves radish biomass. Both experiments indicate that under low stress conditions, biostimulants can replace inorganic fertilizer while simultaneously increasing yield. Full article
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Article
Protein Hydrolysates Supplement in the Nutrient Solution of Soilless Grown Fresh Peppermint and Spearmint as a Tool for Improving Product Quality
Agronomy 2021, 11(2), 317; https://doi.org/10.3390/agronomy11020317 - 11 Feb 2021
Cited by 5 | Viewed by 968
Abstract
The present study investigated the potential of fresh peppermint (Mentha × piperita L.) and spearmint (Menthaspicata L.) production on a floating raft system combined with a commercial protein hydrolysate supplement (Amino16®) in a nutrient solution aiming to improve [...] Read more.
The present study investigated the potential of fresh peppermint (Mentha × piperita L.) and spearmint (Menthaspicata L.) production on a floating raft system combined with a commercial protein hydrolysate supplement (Amino16®) in a nutrient solution aiming to improve plant product quality. Three levels of the protein hydrolysate solution (0, 0.25 and 0.50%) were added in the nutrient solution, and the plants were harvested after twenty-four days. Plant growth characteristics were recorded, and nutritional, essential oil and polyphenolic composition were determined in fresh tissue. The addition of protein hydrolysates did not affect the fresh or dry weight but reduced plant height. Nitrate content significantly decreased, while total chlorophyll and essential oil content increased in both species. Moreover, the protein hydrolysate solution further increased total antioxidant capacity, total soluble phenol and carotenoid contents in spearmint plants, while it did not affect the essential oil and polyphenolic composition in both species. In conclusion, protein hydrolysates solution may be added in the nutrient solution, to improve the quality of peppermint and spearmint grown in a floating system, without adverse effects on crop yield or the essential oil and polyphenolic profile. Full article
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Article
Assessment of the Possibilities of Using Cross-Linked Polyacrylamide (Agro Hydrogel) and Preparations with Biostimulation in Building the Quality Potential of Newly Planted Apple Trees
Agronomy 2021, 11(1), 125; https://doi.org/10.3390/agronomy11010125 - 11 Jan 2021
Cited by 3 | Viewed by 969
Abstract
The research was carried out in a commercial apple orchard in southeastern Poland. The aim of the research was to evaluate the effect of fertilizer with biostimulation and humic acids with algae extracts and agrogel on the reception and growth of newly planted [...] Read more.
The research was carried out in a commercial apple orchard in southeastern Poland. The aim of the research was to evaluate the effect of fertilizer with biostimulation and humic acids with algae extracts and agrogel on the reception and growth of newly planted maiden apple trees of the ‘Gala Must’ variety. One-year-old budwoods were planted annually on the site where fruit trees had grown for 20 years. For the purpose of the experiment, old trees were grubbed up every year in autumn. The experiment assessed the growth and quality of apple trees in the fall of the first year after planting them permanently using a biostimulator in the form of fertilizer and agrogel. On the basis of 3-year studies, it was shown that the application of the assessed preparations had a positive effect on the quality parameters of the trees. The experiment showed the positive effect of the preparation with biostimulation on the best growth and quality parameters every year, which was confirmed by the multidimensional cluster analysis. The fact that the use of agrogel significantly modified the height of the evaluated apple trees in the second year of the study, when lower amounts of rainfall were recorded, is particularly noteworthy. Full article
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Article
Systematic Investigation of the Effects of a Novel Protein Hydrolysate on the Growth, Physiological Parameters, Fruit Development and Yield of Grapevine (Vitis Vinifera L., cv Sauvignon Blanc) under Water Stress Conditions
Agronomy 2020, 10(11), 1785; https://doi.org/10.3390/agronomy10111785 - 14 Nov 2020
Cited by 4 | Viewed by 979
Abstract
In the last decade climate change has impacted viticulture and water deficit has become a major concern in fruit production. Many studies have been carried out to determine the grapevine response to environmental changes and to identify key genetic traits to be used [...] Read more.
In the last decade climate change has impacted viticulture and water deficit has become a major concern in fruit production. Many studies have been carried out to determine the grapevine response to environmental changes and to identify key genetic traits to be used in grapevine breeding. However, in order to better manage climate-related risks, novel viticultural practices are urgently needed. A promising solution for a more sustainable model of viticulture involves the use of biostimulants. In this study, the effectiveness of a novel biostimulant (APR®) belonging to the group of protein thermal hydrolysates was tested on grapevine plants subjected to progressive water deficit conditions. Our results showed that this compound applied to roots before imposing water deprivation mitigates the consequences of stress by sustaining the growth of the younger vegetative organs and limiting the extent of cell dehydration; this positive impact on the plant’s physiological state persisted during the recovery phase. Furthermore, at the end of the growing season, plants treated with the biostimulant, both in optimal water conditions and under water stress, exhibited a greater accumulation of biomass in the aerial part (6.8% and 21.3 %, respectively) and a higher berry diameter (3.4 % and 9.5 %, respectively). Additional work through field trials will be necessary to further substantiate these results and to translate this knowledge into specific practices that grape growers can easily adopt. Full article
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Article
Modification of Yield and Fiber Fractions Biosynthesis in Phaseolus vulgaris L. by Treatment with Biostimulants Containing Amino Acids and Seaweed Extract
Agronomy 2020, 10(9), 1338; https://doi.org/10.3390/agronomy10091338 - 05 Sep 2020
Cited by 7 | Viewed by 1376
Abstract
The most serious of these is to stimulate the development of sustainable and, at the same time, environmentally friendly systems. Therefore, this study aimed to determine the effect of two biostimulants on the bean yield and fiber fractions in seeds: neutral-detergent fiber, acid-detergent [...] Read more.
The most serious of these is to stimulate the development of sustainable and, at the same time, environmentally friendly systems. Therefore, this study aimed to determine the effect of two biostimulants on the bean yield and fiber fractions in seeds: neutral-detergent fiber, acid-detergent fiber, lignin, cellulose, and hemicellulose. The field experiment performed in 2016–2018 in Poland. Over the growing season, plants were treated with biostimulants seaweed extracts (concentrations of 0.7% and 1%) and amino acids (0.3% and 0.5%) based products. Plants were sprayed a single time in the Biologische Bundesanstalt, Bundessortenamt and Chemical industry (BBCH) 13–15 phenological phases and a double spray in the BBCH 13–15 and 61. The study showed a significant increase in bean yield (average 32.08% compare to control) when seaweed extracts was used in the form of a double spray at a higher concentration. In the case of the application of amino acids-based product, the best results (increase of 21.97%) were obtained using a double spray at a lower concentration. It was found that the tested biostimulants changed the fiber fractions of bean seeds. The acid-detergent fiber (ADF) content was the highest (average increase of 2%) after double plant treatment with seaweed extracts based product. While the increased concentration of neutral-detergent fiber (NDF) (over 4%) resulted from double spraying with lower concentration of this biostimulant. The increase in the lignin (ADL) (1.12%), hemicellulose (HCEL) (4.54%), and cellulose (CEL) (0.91%) represented plant response to the double application of this biostimulant in the higher concentration. The results indicated also that the use of amino acids-based product caused an increase in the ADF (0.28%), NDF (10.27%), ADL (0.63%), and HCEL (9.99%) contents in bean seeds as an effect of double plant treatment with this biostimulant at lower concentration. Full article
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Article
Effect of Biostimulants on Apple Quality at Harvest and After Storage
Agronomy 2020, 10(8), 1214; https://doi.org/10.3390/agronomy10081214 - 18 Aug 2020
Cited by 4 | Viewed by 1831
Abstract
Nutritional unbalances, such as calcium deficiency at the fruit level, are generally the causative agent of post-harvest disorders in apples. Foliar application of Ca as calcium chloride is the current solution to increase Ca concentration in apples, even though the effectiveness of this [...] Read more.
Nutritional unbalances, such as calcium deficiency at the fruit level, are generally the causative agent of post-harvest disorders in apples. Foliar application of Ca as calcium chloride is the current solution to increase Ca concentration in apples, even though the effectiveness of this approach is often not satisfactory. In this research, we tested the efficacy of a combined application of Ca with selected biostimulants to improve apple quality and to reduce the incidence of storage disorders. The experiment was conducted in two “Jonathan” apple orchards that differed in management systems and characteristics. Tree canopies were sprayed with calcium chloride alone and in combination with a commercial product containing zinc and silicon or a seaweed extract. The seaweed extract increased apple quality by boosting the reddish coloration (+32% of color index) and by enhancing final anthocyanin concentration of fruit skin. Both biostimulants significantly reduced (by 20%) the incidence of the physiological disorder, known as “Jonathan spot”, after 160 days of storage. Increased concentration of nutrients (Ca, Zn, and Mn) in the skin of apples after biostimulant applications, together with changes of the phenolic profile during the storage, are discussed as the possible causes of the reduced fruit susceptibility to post-harvest disorders. Full article
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Article
Impact of New Micro Carbon Technology Based Fertilizers on Growth, Nutrient Efficiency and Root Cell Morphology of Capsicum annuum L.
Agronomy 2020, 10(8), 1165; https://doi.org/10.3390/agronomy10081165 - 08 Aug 2020
Cited by 4 | Viewed by 1179
Abstract
The aim of this study was to determine the effects of new Micro Carbon Technology (MCT®) fertilizers based on humic acids biologically digested on the growth and development of pepper plants. In this work, the biostimulant effect of MCT® fertilizers [...] Read more.
The aim of this study was to determine the effects of new Micro Carbon Technology (MCT®) fertilizers based on humic acids biologically digested on the growth and development of pepper plants. In this work, the biostimulant effect of MCT® fertilizers was compared to conventional mineral fertilizers. In order to evaluate MCT® fertilizers, a previous chemical characterization (infrared spectroscopy, liquid chromatography and mass spectrometry) of seven MCT® fertilizers was performed. Two fertilization tests of pepper plants were carried out in hydroponic conditions, where the fertilization and the age of the plants were studied in order to evaluate the specific effects on roots and leaves. Plant weight and foliar analysis (chlorophyll indices and nutrients) have been determined. Transmission electron microscopy was used to visualize the morphological differences in the root and leaf cells. Comparison between conventional and MCT® based fertilizers showed that, with the MCT® fertilizers, the plant is exposed to the presence of free amino acids (Glycine and Alanine), polyphenols and humic substances. Although no significant differences were found in plant mass production, the plants fertilized with MCT® products presented better nutritional status than plants treated with conventional fertilization in terms of nutrient content in leaves. Important morphological differences in root cells were found. A large central vacuole that represented the 68–83% of the total root cell area was shown if the MCT® products were used, suggesting significant changes of membrane permeability in terms of water adsorption and consequently nutrient storage. The morphological differences observed in the root cells were more noticeable in adult plants. Full article
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Article
Effect of Reduced Nitrogen and Supplemented Amino Acids Nutrient Solution on the Nutritional Quality of Baby Green and Red Lettuce Grown in a Floating System
Agronomy 2020, 10(7), 922; https://doi.org/10.3390/agronomy10070922 - 27 Jun 2020
Cited by 15 | Viewed by 1226
Abstract
Excessive nitrogen fertilization results in nitrate accumulation in leafy vegetables. Reducing the dose of mineral nitrogen or using alternate fertilizers lowers the nitrate accumulation; however, a critical minimum level of mineral nitrogen is necessary to maintain yield and nutritional quality. The aim of [...] Read more.
Excessive nitrogen fertilization results in nitrate accumulation in leafy vegetables. Reducing the dose of mineral nitrogen or using alternate fertilizers lowers the nitrate accumulation; however, a critical minimum level of mineral nitrogen is necessary to maintain yield and nutritional quality. The aim of this study was to evaluate the effect of two levels of mineral nitrogen (100% and 50%) and three levels of an amino acid solution (0, 0.3, and 0.9%) in the nutrient solution of two baby lettuce cultivars (green and red) grown in a floating system. Nitrogen reduction did not affect yield (12.9–13.4 and 11.0–11.3 g/plant, respectively) but reduced nitrate accumulation (by 43 and 19%, respectively) in both green and red lettuce, while enhancing phenolic content (by 28%) and antioxidant capacity (by 69%) in green lettuce and soluble solid (by 7%) and total chlorophyll content (by 9%) in red lettuce. Although nitrate accumulation was prevented (< 355 mg/kg FW) and most nutritional components increased in both lettuce types by amino acids supplementation, plant growth was negatively affected, especially in red lettuce, in both concentrations of amino acids (reduction by 9 and 35% in 0.3 and 0.9%, respectively). In both lettuce types, proline content increased by 0.9% amino acids supplementation (by 45%), implying a probable induction of a stress condition. Mineral nutrients were slightly affected by nitrogen reduction, which was probably perceived as an abiotic stress. Full article
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Review

Jump to: Research

Review
Rate and Timing of Application of Biostimulant Substances to Enhance Fruit Tree Tolerance toward Environmental Stresses and Fruit Quality
Agronomy 2022, 12(3), 603; https://doi.org/10.3390/agronomy12030603 - 28 Feb 2022
Cited by 1 | Viewed by 886
Abstract
Biostimulants represent an important category of agricultural inputs characterized by multiple functions. They are used to assist crop growth, yield and to enhance the final quality of produces. Their classification is generally based on claims (i.e., which services they provide to the crop), [...] Read more.
Biostimulants represent an important category of agricultural inputs characterized by multiple functions. They are used to assist crop growth, yield and to enhance the final quality of produces. Their classification is generally based on claims (i.e., which services they provide to the crop), even though their biological effects are often species-dependent and highly influenced by external factors (i.e., the growing conditions). This review provides a survey of the available scientific literature on the use of biostimulant substances in fruit production, with the specific aim to clarify their predominant mode and time of application. An extremely varied scenario emerged where foliar treatments are common for seaweed extracts, humic and fulvic acids, and where protein hydrolysates and silicon are applied both to the soil (drench) or sprayed to the canopy. Dosages were difficult to compare between the considered studies given the wide range of tested products and the uncertainty in their actual composition. Regarding the number of applications, biostimulants are generally applied following a calendar-approach, covering most of the growing season. When their use is intended to enhance crop tolerance toward environmental stresses, biostimulants are mainly applied before the stressful event to prime plant physiological defenses. Further studies based on multiple-year research projects and standard methodological protocols are urgently needed to verify a clear compliance with biostimulant claims and to evaluate their cost-effectiveness for the fruit production sector. Full article
Review
Plant Biostimulants: A Categorical Review, Their Implications for Row Crop Production, and Relation to Soil Health Indicators
Agronomy 2021, 11(7), 1297; https://doi.org/10.3390/agronomy11071297 - 26 Jun 2021
Cited by 14 | Viewed by 3437
Abstract
Plant biostimulants are specialty products used to increase crop production and are quickly becoming common in the agricultural seed and chemical marketplace. Unlike traditional crop inputs, such as fertilizers or pesticides, biostimulants are unique in that a single product may have multiple avenues [...] Read more.
Plant biostimulants are specialty products used to increase crop production and are quickly becoming common in the agricultural seed and chemical marketplace. Unlike traditional crop inputs, such as fertilizers or pesticides, biostimulants are unique in that a single product may have multiple avenues for influencing crop growth and development based on both the timing and the placement of application. This review presents a summary of the current status and descriptions of plant biostimulants with available literature on their uses in the row crop production of maize (Zea mays L.), soybean (Glycine max (L.) Merr.), wheat (Triticum aestivum), and other major crop species. Biostimulants have much potential to improve crop production through enhanced yields, grain quality, and increased sustainability of agronomic production systems, particularly in relation to nutrient management. However, there is great variability in the efficacy of biostimulants and a limited understanding of the mechanisms responsible in field-tested scenarios where differences are observed. These unknown mechanisms may align with the recognized soil health indicators, providing opportunities for unrealized biostimulant potential beyond crop growth and development. This review aims to identify the predominant types of crop biostimulants, the known understandings of their modes of action, and examples of their current field efficacy with an outlook for their future. Full article
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Review
Health-Promoting Properties of Plant Products: The Role of Mycorrhizal Fungi and Associated Bacteria
Agronomy 2020, 10(12), 1864; https://doi.org/10.3390/agronomy10121864 - 26 Nov 2020
Cited by 15 | Viewed by 1335
Abstract
The concept of food quality, traditionally based on nutritional and sensory properties, has recently acquired an additional meaning, referring to the health-promoting properties of plant products, that are ascribed to plant secondary metabolites called phytochemicals, primarily represented by polyphenolic compounds and glucosinolates. The [...] Read more.
The concept of food quality, traditionally based on nutritional and sensory properties, has recently acquired an additional meaning, referring to the health-promoting properties of plant products, that are ascribed to plant secondary metabolites called phytochemicals, primarily represented by polyphenolic compounds and glucosinolates. The diversity and content of phytochemicals in plant products are affected by different variables, such as plant genotype, agronomic factors, and arbuscular mycorrhizal fungi (AMF), which establish mycorrhizal symbioses with most crops, including cereals, legumes, vegetables, fruit trees, sunflower, cotton, and sugarcane. AMF and associated bacteria enhance plant growth and health, and affect the production of polyphenols and carotenoids, and the activity of antioxidant enzymes. The production of health-promoting phytochemicals was shown to be differentially modulated by different AMF isolates and bacterial strains, in several food plants, i.e., tomato, lettuce, strawberry, artichoke, maize, grapevine, sunflower. Here, we provide an overview of recent studies concerning the multiple roles played by AMF and associated bacteria in the modulation of the biosynthesis of plant secondary metabolites with health-promoting activity, and discuss the development of designed multifunctional consortia to be used in sustainable agriculture. Full article
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