Special Issue "Effects of Biostimulants and Bioeffectors on Plant Growth"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Agricultural Engineering".

Deadline for manuscript submissions: closed (15 January 2021).

Special Issue Editor

Prof. Dr. Yoshiharu Fujii
Website
Guest Editor
Tokyo University of Agriculture and Technology, Fuchu, Tokyo 1838509, Japan
Interests: allelopathy; plant–plant interactions; plant–microbe interactions; bioactive natural chemicals; weed control; organic agriculture; sustainability in agriculture

Special Issue Information

Dear Colleagues,

Biostimulants include organic compounds and microorganisms that are applied to plants or soils to improve crop yield, quality, vigour, and tolerance to insects, diseases, weeds, or abiotic stresses. Thus, these unique bioactive compounds eventually contribute to the robustness of soil and plants, whilst enhancing productivity even in harsh environmental conditions and despite climate change. Bioeffectors are active naturally occurring compounds or viable microorganisms which directly or indirectly affect plant performance and thus have the potential to reduce fertilizer and agrochemicals use in crop production. Allelopathy and allelochemicals are related concepts according to which bioactive substances produced by plants (and some other organisms) influence the germination, growth, survival, and reproduction of other organisms. With an increasing world population, farmers will need to increase crop production either by increasing the amount of cultivated fields or by enhancing productivity through the adoption of new or improved agricultural techniques. In effect, biostimulants and bioeffectors can be further explored to improve crop productivity whislt ensuring the sustainabilty of the environment.

This Special Issue will focus on the effects of biostimulants and bioeffectors on plant growth. Novel research, reviews, and opinion articles on the basic principles of biostimulants and bioeffectors function, from the chemical level to the field level, toward their effective use in future agriculture are welcome.

Prof. Dr. Yoshiharu Fujii
Guest Editor

Manuscript Submission Information

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Keywords

  • biostimulants
  • bioeffectors
  • microorganisms
  • crop production
  • crop quality
  • allelopathy
  • allelochemicals
  • organic agriculture
  • soil rubustness
  • climate change

Published Papers (11 papers)

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Research

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Open AccessArticle
Cladosporium sp. Isolate as Fungal Plant Growth Promoting Agent
Agronomy 2021, 11(2), 392; https://doi.org/10.3390/agronomy11020392 - 23 Feb 2021
Viewed by 157
Abstract
Cladosporium species are active in protecting plants against different biotic and abiotic stresses. Since these species produced a wide range of secondary metabolites responsible for the adaptation to new habitats, plant health and performance, they are of great interest, especially for biostimulants in [...] Read more.
Cladosporium species are active in protecting plants against different biotic and abiotic stresses. Since these species produced a wide range of secondary metabolites responsible for the adaptation to new habitats, plant health and performance, they are of great interest, especially for biostimulants in agriculture. Cladosporium sp. produces protein hydrolysates (PHs), a class of biostimulants, by cultivation on medium with keratin wastes (feathers) as carbon and energy sources. The aim of this study was to select a Cladosporium isolate with potential to be used as plant growth promoting agent. The characteristics of Cladosporium isolates as plants biostimulants were evaluated through several tests, such as: antagonism versus plants pathogens, effect on plant growth of secreted volatiles produced by isolates, secretion of hydrolytic enzymes, production of 3-indole acetic acid, zinc and phosphorous solubilization, capacity to promote tomato seedlings growth (pot experiments). Cladosporium isolate T2 presented positive results to all tests. Encouraging results were obtained treating tomato seedlings with PHs from isolate Cladosporium T2 cultured on medium supplemented with 1% (w/w) chicken feathers, for which growth parameters, such as stem weight, stem height, and root weight were significantly higher by 65%, 32%, and 55%, respectively, compared to those treated with water. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
The Combined Effects of Gibberellic Acid and Rhizobium on Growth, Yield and Nutritional Status in Chickpea (Cicer arietinum L.)
Agronomy 2021, 11(1), 105; https://doi.org/10.3390/agronomy11010105 - 08 Jan 2021
Cited by 1 | Viewed by 329
Abstract
Plant growth regulators and Rhizobium are actively involved in the regulation of flowering, pod formation, nodulation, and ultimately the growth and yield of legumes. However, very limited information is available on the combined effect of gibberellic acid (GA3) and Rhizobium on [...] Read more.
Plant growth regulators and Rhizobium are actively involved in the regulation of flowering, pod formation, nodulation, and ultimately the growth and yield of legumes. However, very limited information is available on the combined effect of gibberellic acid (GA3) and Rhizobium on growth attributes and yield of legume crops. This experiment was designed to fill this gap by studying the performance of chickpea under exogenous application of GA3 (10−4 and 10−5 M) alone and in combination with Rhizobium. Exogenous application of GA3 (10−5 M) combined with rhizobium inoculation gave the highest values for number of nodules per plant (16) and their dry biomass (0.22 g). Moreover, GA3 application and seed inoculation with Rhizobium, when applied singly, significantly enhanced chickpea growth. However, the most promising results were obtained by the inoculation of Rhizobium accompanied with GA3 (10−5 M). Plant height, grain and stover yield, and chlorophyll contents were enhanced up to 35%, 39%, 21%, and 51%, respectively. Likewise, the bioaccumulation of macronutrients (N, P and K) was maximum in plants receiving both Rhizobium inoculation and GA3 application. It is concluded that the combined application of Rhizobium and GA3 has synergistic effects on the growth, yield, and nutrient contents of chickpea. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
Italian Ryegrass (Lolium multiflorum Lam.) Fiber Fraction Content and Dry Matter Digestibility Following Biostimulant Application against the Background of Varied Nitrogen Regime
Agronomy 2021, 11(1), 39; https://doi.org/10.3390/agronomy11010039 - 27 Dec 2020
Viewed by 432
Abstract
An experiment was conducted to determine the effect of an application of biostimulants, against the background of varied nitrogen regime, on the share of neutral detergent fraction (NDF), acid detergent fraction (ADF), and acid detergent lignin (ADL) in the crude fiber fraction of [...] Read more.
An experiment was conducted to determine the effect of an application of biostimulants, against the background of varied nitrogen regime, on the share of neutral detergent fraction (NDF), acid detergent fraction (ADF), and acid detergent lignin (ADL) in the crude fiber fraction of Italian ryegrass as well as its digestibility. A field experiment was arranged as a randomized subblock design (split-plot) with three replicates at the Siedlce Experimental Unit of the University of Natural Sciences and Humanities in Poland in 2013. The following factors were examined: type of biostimulant: Algex, Tytanit, Asahi SL and a control; nitrogen application rate: 0 (control); 120 and 180 kg·ha−1. There were confirmed positive effects resulting from an application of biostimulants in Italian ryegrass cultivation. There was confirmed the assumed hypothesis that an application of both natural and synthetic biostimulants will make it possible to improve the feeding value of grasses by reducing the fiber fraction. Particular attention should be paid to the biostimulant Algex whose application in Italian ryegrass cultivation produced the most beneficial response in terms of the share of NDF, ADF, and ADL fractions, which resulted in the greatest increase in the plant dry matter digestibility. Increasing nitrogen rates significantly reduced the quantity of analyzed fiber fractions, and increased grass digestibility. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
Open AccessArticle
Effect of Foliar Applied Acetylsalicilic Acid on Wheat (Triticum aestivum L.) under Field Conditions
Agronomy 2020, 10(12), 1918; https://doi.org/10.3390/agronomy10121918 - 06 Dec 2020
Viewed by 637
Abstract
The exogenous application of salicylic acid prevents plant damage caused by various abiotic stresses (drought, high and low temperatures, salinity) and helps plants to build resistance to biotic stresses (pathogens). Acetylsalicylic acid, which is a synthetic salicylic acid derivative, has the same properties. [...] Read more.
The exogenous application of salicylic acid prevents plant damage caused by various abiotic stresses (drought, high and low temperatures, salinity) and helps plants to build resistance to biotic stresses (pathogens). Acetylsalicylic acid, which is a synthetic salicylic acid derivative, has the same properties. In the face of climate change and a greater likelihood of extreme weather events, the use of these acids can significantly help to ensure proper growth and development of plants, especially sensitive species, even under stress conditions. The problem, however, is choosing the right dose (concentration) and time of application, and individual species sensitivity. The aim of the study was to assess the effect of acetylsalicylic acid on the growth and yield parameters of spring wheat. A field trial was carried out in 2013 and 2014 at the Institute of Plant Protection—National Research Institute in Poznan (Poland). The experiment was established on spring wheat cv. ‘Tybalt’, in four replications. Acetylsalicylic acid was tested in two concentrations: 0.3 and 0.5 mM. Each concentration was applied to the crop twice at growth stage BBCH 29 (end of tillering) and 7 days afterwards, and at growth stage BBCH 37 (flag leaf just visible) and 7 days afterwards. The study evaluated 12 traits of the crop, including plant height, chlorophyll content in the flag leaf, length of the ear, and quality and quantity parameters of the yield. The study showed that both the selection of the appropriate concentration and the time of acetylsalicylic acid application have a significant impact on the growth and development of the wheat. The acetylsalicylic acid increased the amount of chlorophyll in the leaves, the number of grains in the ear, the mass of a thousand grains, and grain yield. The present study did not confirm significant differences between the acetylsalicylic acid concentrations. The concentration of 0.5 mM proved more effective only for such traits as plant height and protein content in the grain. The study showed that it is not the concentration but the time of acetylsalicylic acid application that is more important for the growth of the wheat. Although there were no significant differences between the effects of earlier and later application time on plant height or chlorophyll content, most of the structural and qualitative parameters of the yield (number of grains in the ear, grain density, grain hardness, protein, gluten and starch content) were better after later application of acetylsalicylic acid (GS BBCH 37). Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
Growth Promotion, Nutrition Levels, and Antioxidant Activity in Peucedanum japonicum Thunb. under Various Plant Extracts
Agronomy 2020, 10(10), 1494; https://doi.org/10.3390/agronomy10101494 - 01 Oct 2020
Viewed by 420
Abstract
This study examined the growth promotion effects of selected water extracts on Peucedanum japonicum. As secondary considerations, the mineral nutrition levels were measured in both the extracts and the test plant. In addition, the levels of chlorophyll and the photosynthetic efficiency in [...] Read more.
This study examined the growth promotion effects of selected water extracts on Peucedanum japonicum. As secondary considerations, the mineral nutrition levels were measured in both the extracts and the test plant. In addition, the levels of chlorophyll and the photosynthetic efficiency in the test plant were analyzed after the treatment of selected plant extracts. Finally, the total phenol, flavonoid contents, and DPPH (2,2′-diphenyl-1-picrylhydrazyl) radical scavenging activity in Peucedanum japonicum leaves were determined after the extract treatments. The shoot fresh weight of Peucedanum japonicum increased in response to all the extracts used, and in some cases increased at rates of 16–49% after extract treatments. Compared to the control, the photosynthetic efficiency and chlorophyll content of the Peucedanum japonicum plants did not vary significantly. In measuring the macro and microelements in the extracts, those with the highest levels were not necessarily the most effective growth promotors of Peucedanum japonicum plants. However, nutrition levels increased significantly in Peucedanum japonicum leaves after extract treatments. The total phenol contents in the Peucedanum japonicum leaves increased significantly when treated with the soybean stem extracts at 3%, Chinese chive extract at 0.5–3%, onion extract at 0.5%, or tomato extract at 3%. The total flavonoid contents in the Peucedanum japonicum leaves treated with the soybean leaf extracts at 0.5 to 3% increased by 23–36% compared to the control, but there were no differences with other extracts. Thus, the plant extracts tested in this study showed improved growth promotion, mineral contents, total phenol, total flavonoid contents, and DPPH radical scavenging activity. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
The Influence of Red Light (RL) and Effective Microorganism (EM) Application on Soil Properties, Yield, and Quality in Wheat Cultivation
Agronomy 2020, 10(8), 1201; https://doi.org/10.3390/agronomy10081201 - 15 Aug 2020
Viewed by 657
Abstract
The aim of the study was to determine the impact of red light (RL) and effective microorganisms (EMs) on the wheat yield of grain and straw, as well as the quality (protein, carbohydrates, gluten, index of sedimentation (SDS index), germination capacity). Moreover, the [...] Read more.
The aim of the study was to determine the impact of red light (RL) and effective microorganisms (EMs) on the wheat yield of grain and straw, as well as the quality (protein, carbohydrates, gluten, index of sedimentation (SDS index), germination capacity). Moreover, the experiments measured the granulometric composition and pH of soil, as well as its content of microelements and major nutrients, including heavy metals. The field experiment was conducted in 2017, 2018, and 2019 at the experimental station (Felin) of the University of Life Sciences in Lublin (Poland). The best results in terms of overall yield, protein content, and SDS index were obtained after the red light treatment (RL). The three-year application of effective microorganisms (EMs) in the soil had a positive impact, relative to the control, on the grain yield, straw yield, starch, SDS index, and germination capacity. A slight decrease was observed in terms of the protein content. After the application of effective microorganisms (EMs) in soil, changes were observed in the soil’s granulometric composition, pH, humus, and microelements. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
Open AccessArticle
Effect of Compound Biochar Substrate on the Root Growth of Cucumber Plug Seedlings
Agronomy 2020, 10(8), 1080; https://doi.org/10.3390/agronomy10081080 - 26 Jul 2020
Cited by 2 | Viewed by 576
Abstract
Since plug seedling plays a key role in automatic transplanting, this work aimed to explore the effect biochar has on the root growth of plug seedlings. The physicochemical properties tests showed that the addition of biochar in the peats could increase the porosity, [...] Read more.
Since plug seedling plays a key role in automatic transplanting, this work aimed to explore the effect biochar has on the root growth of plug seedlings. The physicochemical properties tests showed that the addition of biochar in the peats could increase the porosity, pH, and EC values of the substrate, and the substrates treated with 0%, 10%, 20%, and 30% biochar could meet the requirements of seedling raising. The water retention of the substrate was superior with the increase of biochar proportion, and the nitrogen release significantly decreased with the increase of the biochar proportion. Our results demonstrated that the substrate with 10% biochar-treated apparently promoted the growth of seedlings and root systems, even the length of the root-tip cells. However, the substrates with 40% and 50% biochar-treated obviously inhibited the growth of seedlings and root systems. It was noticed that the strength of substrate with appropriate biochar proportion was enhanced, as well. Under the interaction of strong root system and solid substrate, the compressive strength of the substrate with 20% and 10% biochar-treated was much better than others, especially that of 40% and 50% biochar-treated, which efficiently satisfied the requirements of automatic seedling picking. The biochar may have a good application prospect in seedling raising. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
Effect of Salt-Tolerant Bacterial Inoculations on Rice Seedlings Differing in Salt-Tolerance under Saline Soil Conditions
Agronomy 2020, 10(7), 1030; https://doi.org/10.3390/agronomy10071030 - 16 Jul 2020
Cited by 1 | Viewed by 558
Abstract
Salt-tolerant plant growth-promoting rhizobacteria (PGPR) could be an alternative to alleviate salinity problems in rice plants grown in the coastal areas. This study was conducted to isolate and characterize salt-tolerant PGPR and observe their effects on the physiological and biochemical properties of rice [...] Read more.
Salt-tolerant plant growth-promoting rhizobacteria (PGPR) could be an alternative to alleviate salinity problems in rice plants grown in the coastal areas. This study was conducted to isolate and characterize salt-tolerant PGPR and observe their effects on the physiological and biochemical properties of rice plants grown under non-saline and saline glasshouse conditions. Three strains were selected based on their salt-tolerance and plant growth-promoting properties under in vitro saline conditions. These strains were identified as Bacillus tequilensis (UPMRB9), Bacillus aryabhattai (UPMRE6), and Providencia stuartii (UPMRG1) using a 16S rRNA technique. The selected strains were inoculated to three different rice varieties, namely BRRI dhan67 (salt-tolerant), Putra-1 (moderate salt-tolerant), and MR297 (salt-susceptible) under glasshouse conditions. Results showed that the MR297 rice variety inoculated with UPMRB9 produced the highest total chlorophyll content, with an increment of 28%, and lowest electrolyte leakage of 92%. The Putra-1 rice variety also showed a 156% total dry matter increase with the inoculation of this bacterial strain. The highest increase of relative water content and reduction of Na/K ratio were found upon inoculation of UPMRE6 and UPMRB9, respectively. The biggest significant effects of these bacterial inoculations were on relative water content, electrolyte leakage, and the Na/K ratio of the BRRI dhan67 rice variety under saline conditions, suggesting a synergistic effect on the mechanisms of plant salt-tolerance. This study has shown that the application of locally-isolated salt-tolerant PGPR strains could be an effective long-term and sustainable solution for rice cultivation in the coastal areas, which are affected by global climate change. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
Study of Allelopathic Interaction of Essential Oils from Medicinal and Aromatic Plants on Seed Germination and Seedling Growth of Lettuce
Agronomy 2020, 10(2), 163; https://doi.org/10.3390/agronomy10020163 - 23 Jan 2020
Cited by 5 | Viewed by 1153
Abstract
Medicinal and aromatic plants have the ability to transmit volatile allelochemicals and affect their surrounding organisms. In this regard, their interaction should also be considered. The inhibitory effects of 112 essential oils on lettuce seed and seedling were investigated by cotton swab method. [...] Read more.
Medicinal and aromatic plants have the ability to transmit volatile allelochemicals and affect their surrounding organisms. In this regard, their interaction should also be considered. The inhibitory effects of 112 essential oils on lettuce seed and seedling were investigated by cotton swab method. Germination (G%), Mean germination time (MGT), Lethal of embryo (L%), dormancy (D%), radicle growth (R%), and hypocotyl growth (H%) were measured. Two methods were used for evaluating allelopathic interaction effects: the simplified modified dilution check-board technique (SMCT) and the isobologram. Thymus daenensis had the highest inhibitory effect on G% (IC50 = 2.9 ppm) and the most lethal effect on the embryo (LC50 = 7.2 ppm). Thymus transcaspicus, Dracocephalum moldavica, Artemisia sieberi and Amomum subulatum had the greatest effect on MGT. Ziziphora tenuior, Trachyspermum ammi and Pelargonium graveolens had the highest effect on D%. Origanum vulgare was the strongest growth inhibitor. The highest synergistic effect on G% was in A. subulatum + Mentha suaveolens, on H% was related to Perovskia abrotanoides + T. daenensis, and on R% was observed in Artemisia vulgaris + M. suaveolens. The results of this study can lead to identification of new phytotoxic compounds in EOs and control weeds more effectively. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Open AccessArticle
Plant Biostimulant Effects of Baker’s Yeast Vinasse and Selenium on Tomatoes through Foliar Fertilization
Agronomy 2020, 10(1), 133; https://doi.org/10.3390/agronomy10010133 - 16 Jan 2020
Cited by 2 | Viewed by 986
Abstract
The application of selenium (Se) to tomatoes enhances accumulation of bioactive compounds. The physiological window of Se is very narrow, and Se overdose reduces the yield. Glycine betaine was shown to reduce Se’s negative effects on plants and to potentiate its beneficial effects. [...] Read more.
The application of selenium (Se) to tomatoes enhances accumulation of bioactive compounds. The physiological window of Se is very narrow, and Se overdose reduces the yield. Glycine betaine was shown to reduce Se’s negative effects on plants and to potentiate its beneficial effects. In this study, baker’s yeast vinasse (BYV), as an affordable source of glycine betaine, was tested for its interaction with Se in an optimized foliar fertilizer. The application dose was selected after a laboratory experiment, wherein assays on plant height, leaves surfaces, stomatal conductance, and chlorophyll fluorescence were done. The Se and BYV supplemented foliar fertilizers were tested for their effects on accumulation of bioactives in drip-irrigated tomatoes cultivated in a greenhouse. Under laboratory conditions, assays demonstrated Se and BYV induced effects on tomatoes plants. Both the stomatal conductance and photosynthesis efficiency increased compared to a water treated control. The greenhouse experiment demonstrated that BYV and Se addition increases the number of tomato fruits in the “extra” marketable class and enhances the accumulation of ascorbic acid, carotenes, polyphenols, and flavonoids. The effects depend on the composition of the foliar fertilizer, the most significant effects being recorded for the foliar applied product with the highest BYV and nitrogen content. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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Review

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Open AccessReview
Agricultural Uses of Juglone: Opportunities and Challenges
Agronomy 2020, 10(10), 1500; https://doi.org/10.3390/agronomy10101500 - 01 Oct 2020
Cited by 1 | Viewed by 611
Abstract
Application of conventional synthetic pesticides and agrochemicals has boosted the yield and productivity of crops by reducing pest infestation and promoting crop growth yet increasing reliance on many of these products poses serious environmental threats. This has led to growing interest in obtaining [...] Read more.
Application of conventional synthetic pesticides and agrochemicals has boosted the yield and productivity of crops by reducing pest infestation and promoting crop growth yet increasing reliance on many of these products poses serious environmental threats. This has led to growing interest in obtaining more environmentally friendly alternatives to conventional pesticides and agrochemicals. Allelochemicals produced by plants, fungi, and microbes offer options for developing novel natural product-based pesticides and agrochemicals that are effective but with lower environmental half-lives. Here, we review the current state of knowledge about the potential use of juglone (5-hydroxy-1,4-naphthoquinone), the allelochemical produced by black walnut trees (Juglans nigra), which has been investigated for applications across a range of different agricultural purposes. We then offer our perspective on what opportunities and challenges exist for harnessing juglone as a component of sustainable agriculture. Full article
(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)
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