Soybean Growth Research Articles

Effects of Potassium Application on Yield, Protein and Oil Content of Selected Soybean Varieties in Trans Nzoia County, Kenya

There is low soybean production due to poor agronomic techniques, such as sub-optimal application of fertilizer among other factors. There are limited studies on the effects of potassium fertilizer application which is crucial in productivity, quality, and drought resistance. A study was conducted at the Kenya Agricultural Livestock and Research Organization, Kitale demonstration farm to determine the effects of potassium fertilizer application on the yield and quality of soybean varieties. A 3 x 4 factorial experiment was laid down in Randomised Complete Block Design and replicated three times. The study had two factors, that is three soybean varieties (DPSB19, Gazelle and SB24) and four levels of potassium (0 [control], 22.5, 45, and 67.5 kg K2O ha-1) applied as sulphate of potash fertilizer (50% K2O) at planting, making a total of 12 treatments. Data collected included number of pods per plant, number of seeds per plant, weight of seed per plant and 1000-seed weight, grain yield, protein and oil content. Data collected was subjected to analysis of variance using Statistical Analysis System version 9.3 and significantly different means separated using Least Significance Difference at α = 0.05. Application of potassium at the rate of 67.5 kg K2O ha-1 resulted to higher number of pods per plant and number of seeds per plant at 78.97 and 243.40, and 44.47 and 141.20 in the varieties DPSB19 and Gazelle, while in SB24 higher recording of 51.23 and 162.40 was observed with 22.5 kg K2­O ha-1. The higher 1000-seed weight was recorded in 22.5 kg K2O ha-1 in DPSB19 and Gazelle varieties, while for SB24 it was recorded in 67.5 kg K2O ha-1. The highest grain yield recorded was 9156.45 kg per ha, in DPSB19 in 22.5 kg K2O ha-1, 4517. 67.5 kg per ha in Gazelle variety in 67.5 kg K2O ha-1 and 6432.78 kg per ha in SB24 variety in 22.5 kg K2O ha-1. The higher percentage oil content was observed in 45 K2O kg ha-1 in DPSB19 (28.48%) and SB24 (23.38%) varieties, and in 22.5 kg K2O ha-1 in Gazelle (19.38%) variety and the higher percentage protein content was recorded in 45 K2O kg ha-1 in DPSB19 (42.99%) and Gazelle (40.56%), and in 45 K2O kg ha-1 in SB24 (48.87%). These findings show that soybean farmers should apply potassium fertilizer for appropriate growth, increased yield, protein and oil content in different soybean varieties. It is recommended that application of potassium at 67.5 kg K2O ha-1 be done for better soybean growth, yield and protein content and application of potassium at 45 kg K2O ha-1 is done for high oil content.

H2 S works synergistically with rhizobia to modify photosynthetic carbon assimilation and metabolism in nitrogen-deficient soybeans.

Hydrogen sulfide (H2 S) performs a crucial role in plant development and abiotic stress responses by interacting with other signalling molecules. However, the synergistic involvement of H2 S and rhizobia in photosynthetic carbon (C) metabolism in soybean (Glycine max) under nitrogen (N) deficiency has been largely overlooked. Therefore, we scrutinised how H2 S drives photosynthetic C fixation, utilisation, and accumulation in soybean-rhizobia symbiotic systems. When soybeans encountered N deficiency, organ growth, grain output, and nodule N-fixation performance were considerably improved owing to H2 S and rhizobia. Furthermore, H2 S collaborated with rhizobia to actively govern assimilation product generation and transport, modulating C allocation, utilisation, and accumulation. Additionally, H2 S and rhizobia profoundly affected critical enzyme activities and coding gene expressions implicated in C fixation, transport, and metabolism. Furthermore, we observed substantial effects of H2 S and rhizobia on primary metabolism and C-N coupled metabolic networks in essential organs via C metabolic regulation. Consequently, H2 S synergy with rhizobia inspired complex primary metabolism and C-N coupled metabolic pathways by directing the expression of key enzymes and related coding genes involved in C metabolism, stimulating effective C fixation, transport, and distribution, and ultimately improving N fixation, growth, and grain yield in soybeans.

Response of soybean and maize roots and soil enzyme activities to biodegradable microplastics contaminated soil

Although biodegradable plastic film is a promising alternative product for reducing polyethylene plastic pollution in agricultural soils, the effects of its residues on plant growth and soil properties remain unclear. In this study, we conducted an experiment to investigate root properties and soil enzyme activities in Poly (butylene adipate-co-terephthalate) microplastics (PBAT-MPs) contaminated soil (0 % (CK), 0.1 %, 0.2 %, 0.5 % and 1 % of dry soil weight) with soybean (Glycine max (Linn.) Merr.) and maize (Zea mays L.). The results show that PBAT-MP accumulation in soil negatively affects root growth, and alter soil enzyme activities, which may then constrain C/N cycling and potential yields. For soybean, the total root length, total root surface area and root biomass decreased by 34 %− 58 %, 34 %− 54 % and 25 %− 40 % at the harvesting stage compared to CK, respectively. The negative effects of PBAT-MPs on maize roots were greater than on soybean roots. The total root length, root surface area and root biomass of maize decreased by 37 %− 71 %, 33 %− 71 % and 24 %− 64 % at the tasseling and harvesting stage, respectively (p < 0.05). Furthermore, a statistical analysis of the data indicates that the inhibition of soybean and maize root growth by PBAT-MP accumulation was mediated by the significantly different impacts of PBAT-MP addition on C-enzyme (β-xylosidase, cellobiohydrolase, β-glucosidase) and N-enzyme activities (leucine-aminopeptidase, N-acetyl-β-glucosaminidase, alanine aminotransferase) in rhizosphere and non-rhizosphere soil, possibly due to interactions with plant-specific root exudates and microbial communities. These findings show the potential risks posed by biodegradable microplastics on the plant-soil system, and suggest that biodegradable plastic film should be applied with caution.

Effect of Sulphur and Zinc Fertilization on Growth and Yield of Soybean [Glycine max (L.) Merrill] under Nagaland Condition

Background: A field experiment was conducted at the Experimental Research Farm of School and Agricultural Sciences and Rural Development (SASRD), Nagaland University, during the Kharif season of 2017 and 2018 to study the effect of sulphur and zinc fertilization for biofortification in soybean (Glycine max L. Merrill) under Nagaland condition. Methods: The experiment was laid out in a Factorial Randomized Block Design (RBD) with 15 treatments combinations viz sulphur (0 kg ha-1, 20 kg ha-1 and 40 kg ha-1), zinc (0 kg ha-1, 5 kg ha-1, 10 kg ha-1, 15 kg ha-1, and 20 kg ha-1) replicated thrice. Result: The results obtained showed that the plant growth and yield attributes were significantly influenced by the treatment combination of S20Zn20. The application of 20 kg S ha-1 showed higher plant height, number of leaves and branches per plant, shoot dry weight, leaf area index (LAI), crop growth rate (CGR), number of nodules and was found to be quite comparable with the treatment of 40 kg S ha-1. The zinc fertilization of 20 kg Zn ha-1 showed greater response by the plant and showed increased plant height, number of leaves and branches per plant, shoot dry weight, leaf area index (LAI) and number of nodules at par with 15 kg Zn ha-1. A higher number of pods (40.48 and 40.89), seed yield of (1.07 t ha-1 and 1.10 t ha-1) and stover yield (1.97 t ha-1 and 2.02 t ha-1) were observed in 20 kg S ha-1 and 20 kg Zn ha-1 fertilization respectively as compared to the other levels of treatments. However, the length of pods, number of seeds per pod, test weight and harvest index did not differ significantly by the treatments.

Bacillus- and Trichoderma-based products control the spiral nematode Helicotylenchus dihystera in soybean

Soybean (Glycine max) is significantly affected by plant-parasitic nematodes. The spiral nematode (Helicotylenchus dihystera) is considered a potential parasite for Brazilian soybean. This study investigated the efficiency of microorganism-based products against H. dihystera in soybean and possible mechanisms involved in the control. Products based on Bacillus and Trichoderma were compared to a chemical nematicide (abamectin). By in vitro tests, all products killed H. dihystera. Production of toxic compounds was tested by using cell-free culture filtrate or by volatile emission. Filtrates of Trichoderma and Bacillus killed more than 85% of H. dihystera. The volatile emitted by Bacillus-based products also killed the nematodes. All products increased soybean growth and controlled H. dihystera in pots with infested soil, where B. amyloliquefaciens-based products stood out. The field experiment confirmed the efficiency of abamectin and Bacillus against H. dihystera. Therefore, the microorganism-based products produced compounds toxic to H. dihystera and benefited soybean under infested soil.

Biologically synthesized zinc and copper oxide nanoparticles using Cannabis sativa L. enhance soybean (Glycine max) defense against fusarium virguliforme

In this study, zinc and copper oxide nanoparticles (NPs) were synthesized using hemp (Cannabis sativa L.) leaves (ZnONP-HL and CuONP-HL), and their antifungal potential was assessed against Fusarium virguliforme in soybean (Glycine max L.). Hemp was selected because it is known to contain large quantities of secondary metabolites that can potentially enhance the reactivity of NPs through surface property modification. Synthesizing NPs with biologically derived materials allows to avoid the use of harsh and expensive synthetic reducing and capping agents. The ZnONP-HL and CuONP-HL showed average grain/crystallite size of 13.51 nm and 7.36 nm, respectively. The biologically synthesized NPs compared well with their chemically synthesized counterparts (ZnONP chem, and CuONP chem; 18.75 nm and 10.05 nm, respectively), confirming the stabilizing role of hemp-derived biomolecules. Analysis of the hemp leaf extract and functional groups that were associated with ZnONP-HL and CuONP-HL confirmed the presence of terpenes, flavonoids, and phenolic compounds. Biosynthesized NPs were applied on soybeans as bio-nano-fungicides against F. virguliforme via foliar treatments. ZnONP-HL and CuONP-HL at 200 μg/mL significantly (p < 0.05) increased (∼ 50%) soybean growth, compared to diseased controls. The NPs improved the nutrient (e.g., K, Ca, P) content and enhanced photosynthetic indicators of the plants by 100–200%. A 300% increase in the expression of soybean pathogenesis related GmPR genes encoding antifungal and defense proteins confirmed that the biosynthesized NPs enhanced disease resistance against the fungal phytopathogen. The findings from this study provide novel evidence of systemic suppression of fungal disease by nanobiopesticides, via promoting plant defense mechanisms.

Optimization of culture medium and bioformulation of rhizobial actinomycetes to enhance soybean plant growth

Abstract. Fatmawati U, Qurrata’aini MR, Rosyidi NW, Sari DP, Santosa S. 2023. Optimization of culture medium and bioformulation of rhizobial actinomycetes to enhance soybean plant growth. Biodiversitas 24: 2912-2918. Actinomycetes are a group of Gram-positive bacteria that are well-known for having plant growth-promoting activity. In an earlier study, Streptomyces sp. strain ASR 58 and Streptomyces sp. strain ASR 67, isolated from soybean rhizosphere, were found to be capable of producing Indole-Acetic Acid (IAA), dissolving phosphate, and stimulating soybean growth. Optimization of culture media and selection of carrier materials for formulation are necessary to maintain actinomycetes' cell viability and plant growth property stability. This study aimed to evaluate several culture media, determine the optimal carrier materials in actinomycetes formulation, and evaluate the effect of actinomycete bioformulation on the soybean plant growth in planta. The sugar potato broth medium was the best in increasing the cell biomass of ASR 67 and co-culture of ASR 58 and ASR 67 compared to other mediums (skim molasses and rice bran broth). The viability of ASR 58 cell (5.3 x 107 CFU/mL), ASR 67 (3.8 x 107 CFU/mL), and its combination of both (4.3 x 107 CFU/mL) was best maintained in talc powder carrier during 10 weeks of storage as revealed by the number of viable cells decreases. Applying ASR 58 and ASR 67 co-culture on talc powder formula enhanced soybean plant biomass four weeks after planting, including plant height, the number of leaves, and root dry weight.

Metal-Tolerant Bioinoculant Pseudomonas putida KNP9 Mediated Enhancement of Soybean Growth under Heavy Metal Stress Suitable for Biofuel Production at the Metal-Contaminated Site

The contamination of agricultural land with heavy metals is a global concern. Agricultural products produced in heavy metal-contaminated soil are prone to metal accumulation, and thus, are less fitted for consumption due to food safety issues. The cultivation of biofuel crops in contaminated soil would provide immediate economic benefit to the landholders while simultaneously reclaiming contaminated sites in the long run. The use of edible soybean for biodiesel production is discouraged due to the negative impact on food security. However, soybean produced in metal-contaminated soil would be suitable for biodiesel production. In this study, the tolerance and metal bioaccumulation potential of Pseudomonas putida KNP9 for Pb and Cd is investigated, and KNP9 is tested for soybean growth enhancement in cadmium and lead-amended soil. The maximum metal tolerance for the Pb and Cd in KNP9 was 1580 µM and 546 µM, respectively. KNP9 was found to be effective in removing both Pb and Cd from the solution. SEM-EDX revealed that KNP9 bioaccumulates both Pb and Cd. In pot trial studies, KNP9 was found to be effective in enhancing soybean growth with respect to untreated control under lead and cadmium stress. Thus, KNP9 inoculation protects soybean plants from the detrimental effects of cadmium and lead stress. Therefore, metal bioaccumulating bacterium P. putida KNP9 inoculation in soybean is a promising strategy for soybean growth enhancement, which could be utilized for enhanced biodiesel production from soybean at metal-contaminated sites.

Effectiveness of indigenous Rhizobium sp. isolates from peatland soils on soybean (Glycine max L. Merril) growth and production

The low productivity of soybeans can be overcome by cultivating them on peatlands, accompanied by the provision of indigenous Rhizobium strains derived from peatlands. Isolating Rhizobium sp. from peatlands is believed to enhance soybean productivity on such land. This study aims to determine the effectiveness of local Riau Rhizobium sp. isolates for soybean cultivation in Riau peatlands. Six isolates of Rhizobium sp. were used in this study, obtained from plants growing on peatlands: IIMB4, IIRM1, IIRM2 from the rhizosphere of Mucuna bracteata, and IIRA4, IIRA2, IIRA6 from the rhizosphere of Acacia crassicarpa. The experiment followed a completely randomized design (CRD), with each treatment replicated four times. The treatments included control, commercial Rhizobium sp., isolates IIMB4, IIRA2, IIRA6, IIRM2, IIRA4, and IIRM1. The results demonstrated that all indigenous Rhizobium sp. isolates from peatlands, particularly IIMB4, effectively formed symbiotic associations with soybean plant roots, improving growth parameters and increasing soybean production. Nevertheless, it is also necessary to assess the effectiveness of these Rhizobium sp. isolates on various other leguminous plant species to identify the most efficient symbiotic isolates across different leguminous crops.

Synergistic Effects of Subsoil Calcium in Conjunction with Nitrogen on the Root Growth and Yields of Maize and Soybeans in a Tropical Cropping System

A large part of Brazilian maize is double-cropped after soybeans, when water shortages are very frequent. A larger root system can mitigate drought stress and enable better nitrogen (N) use. Alleviating acidity and applying gypsum can increase root growth and N-use efficiency in maize, which has a more aggressive root system than soybeans. However, it is not known how these factors interact in integrated cropping systems, or how soybeans respond to them. Soybean and maize root growth and grain yields as affected by soil Ca enrichment using lime and gypsum, along with the N rates applied to maize intercropped with Guinea grass (Megathyrsus maximus), were assessed in a medium-term field experiment. Liming resulted in greater root growth for both crops; however, when lime was used in conjunction with gypsum, root growth was further enhanced. The total maize grain yield was 35% higher compare to the control when gypsum was used in conjunction with lime; however, subsoil Ca enrichment increased the total soybean grain yield by 8% compared to the control. Nitrogen fertilization increased the total maize grain yield by 36%, with a more expressive increase when applying 160 kg ha−1 or more, and despite a positive effect on soybean grain yields in the long term, this response seems not to be a direct effect of the N applied to the maize. Both subsoil Ca enrichment and N application to maize increase root growth and the total yield of the system.

Integration of Remote Sensing and Field Observations in Evaluating DSSAT Model for Estimating Maize and Soybean Growth and Yield in Maryland, USA

Crop models are useful for evaluating crop growth and yield at the field and regional scales, but their applications and accuracies are restricted by input data availability and quality. To overcome difficulties inherent to crop modeling, input data can be enhanced by the incorporation of remotely sensed and field observations into crop growth models. This approach has been recognized to be an important way to monitor crop growth conditions and to predict yield at the field and regional scale. In recent years, satellite remote sensing has provided high-temporal and high-spatial-resolution data that allow for generating continuous time series of biophysical parameters such as vegetation indices, leaf area index, and phenology. The objectives of this study were to use remote sensing along with field observations as inputs to the Decision Support System for Agro-Technology (DSSAT) model to estimate soybean and maize growth and yield. The study used phenology and leaf area index (LAI) data derived from Planet Fusion (daily, 3 m) satellite imagery along with field observation data on crop growth stage, LAI and yield collected at the United State Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center (BARC), Beltsville, Maryland. For maize, a total of 17 treatments (site years) were used (ten treatments for model calibration and seven treatments for validation), while for soybean (maturity groups three and four), a total of 18 treatments were used (nine for calibration and nine for validation). The calibrated model was tested against an independent, multi-location and multi-year set of phenology and yield data (2017–2020) from BARC fields. The model accurately simulated maize and soybean days to flowering and maturity and produced reasonable yield estimates for most fields and years. Model run for independent locations and years produced good results for phenology and yields for both maize and soybean, as indicated by index of agreement (d) values ranging from 0.65 to 0.93 and normalized root-mean-squared error values ranging from 1 to 20%, except for soybean maturity group four. Overall, model performances with respect to phenology and grain yield for maize and soybean were good and consistent with other DSSAT evaluation studies. The inclusion of remote sensing along with field observations in crop-growth model inputs can provide an effective approach for assessing crop conditions, even in regions lacking ground data.

Developing a New Vegetation Index Using Cyan, Orange, and Near Infrared Bands to Analyze Soybean Growth Dynamics

Remote sensing Vegetation Indices (VIs) are simple, effective, and widely used methods for quantitative and qualitative analysis of vegetation cover, vigor, and growth dynamics. This study developed and assessed a new vegetation index (VI) using Cyan, Orange, and Near Infrared (NIR) bands to assess Soybean growth dynamics. The study was conducted at Lakehead University Agriculture Research Station, Thunder Bay, Canada, over four reproductive stages of Soybean growth (R4–R7). Spectral profiles were created for each stage, and the correlation between each spectral band at different stages was tested. There was no linear correlation between different bands except the correlation between the Cyan and Orange bands at R5 and R6 stages. Existing VIs have also been explored using approximately similar band combinations. Based on this analysis, three VIs were proposed for this new camera, and their behavior at different stages was evaluated using Leaf Area Index (LAI). Cyan and Orange spectral values were relatively high in the first and last growing seasons, while NIR values increased dramatically in the mid-growing seasons and decreased in the last stage. VINIR,O,C index showed the best results for mid-growing seasons (correlation with LAI = 0.39 for R5 and R6). VIC,O index showed a high level of details visually (leaves and background) for R4 and R7 than the other indices and correlated highly with LAI (0.48 and −0.5, respectively). Overall, the study provided new VIs that can be used to effectively analyze Soybean growth dynamics, with different VIs showing reliability over different growing stages.

Rhizosphere nutrient availability and nutrient uptake of soybean in response to biochar application

Biochar application in agricultural soils can be highly beneficial to crop productivity in numerous ways. Rhizosphere nutrient dynamics and its relation to nutrient uptake of crops under biochar amendment remain unclear. Therefore, the present study investigated the combined effect of biochar application and incubation on growth, yield, and rhizosphere nutrient availability of soybean (Glycine max L.) plant. A pot experiment was conducted with two biochar applications (with and without biochar) and two incubation conditions (with and without incubation) in a glasshouse. A separate soil column leaching experiment was conducted to test the nutrient retention ability of soil once biochar is amended. Irrespective of the incubation condition, biochar application made a significant increase in pod dry weight. The total nutrient uptake by soybean greatly increased under biochar amendment compared with the plants grown without biochar. When incubation is not done, soybean increased its P and K uptake respectively by 52% and 48% under biochar amendment compared to those without biochar. With incubation, the relevant increases were 42% and 32% respectively. The results from soil column leaching experiment suggest that the application of biochar in planting media could be an effective way to retain soil N by reducing the leaching losses.

Overexpression of soybean GmNAC19 and GmGRAB1 enhances root growth and water-deficit stress tolerance in soybean.

Soybean (Glycine max) is an important crop in agricultural production where water shortage limits yields in soybean. Root system plays important roles in water-limited environments, but the underlying mechanisms are largely unknown. In our previous study, we produced a RNA-seq dataset generated from roots of soybean at three different growth stages (20-, 30-, and 44-day-old plants). In the present study, we performed a transcriptome analysis of the RNA-seq data to select candidate genes with probable association with root growth and development. Candidate genes were functionally examined in soybean by overexpression of individual genes using intact soybean composite plants with transgenic hairy roots. Root growth and biomass in the transgenic composite plants were significantly increased by overexpression of the GmNAC19 and GmGRAB1 transcriptional factors, showing up to 1.8-fold increase in root length and/or 1.7-fold increase in root fresh/dry weight. Furthermore, greenhouse-grown transgenic composite plants had significantly higher seed yield by about 2-fold than control plants. Expression profiling in different developmental stages and tissues showed that GmNAC19 and GmGRAB1 were most highly expressed in roots, displaying a distinct root-preferential expression. Moreover, we found that under water-deficit conditions, overexpression of GmNAC19 enhanced water stress tolerance in transgenic composite plants. Taken together, these results provide further insights into the agricultural potential of these genes for development of soybean cultivars with improved root growth and enhanced tolerance to water-deficit conditions.

Evaluating the Effectiveness of Calcium Silicate in Enhancing Soybean Growth and Yield.

The application of silicon (Si) fertilizer positively impacts crop health, yield, and seed quality worldwide. Si is a "quasi-essential" element that is crucial for plant nutrition and stress response but is less associated with growth. This study aimed to investigate the effect of Si on the yield of cultivated soybean (Glycine max L). Two locations, Gyeongsan and Gunwi, in the Republic of Korea were selected, and a land suitability analysis was performed using QGIS version 3.28.1. The experiments at both locations consisted of three treatments: the control, Si fertilizer application at 2.3 kg per plot (9 m × 9 m) (T1), and Si fertilizer application at 4.6 kg per plot (9 m × 9 m) (T2). The agronomic, root, and yield traits, as well as vegetative indices, were analyzed to evaluate the overall impact of Si. The results demonstrated that Si had consistently significant effects on most root and shoot parameters in the two experimental fields, which led to significantly increased crop yield when compared with the control, with T2 (22.8% and 25.6%, representing an output of 2.19 and 2.24 t ha-1 at Gyeongsan and Gunwi, respectively) showing a higher yield than T1 (11% and 14.2%, representing 1.98 and 2.04 t ha-1 at Gyeongsan and Gunwi, respectively). These results demonstrate the positive impact of exogenous Si application on the overall growth, morphological and physiological traits, and yield output of soybeans. However, the application of the optimal concentration of Si according to the crop requirement, soil status, and environmental conditions requires further studies.

IAA and ACC deaminase producing-bacteria isolated from the rhizosphere of pineapple plants grown under different abiotic and biotic stresses

The roles of plant growth-promoting rhizobacteria in promoting plant growth and soil health, including alteration in plant metabolism and production of phytohormones such as indole-3-acetic acid (IAA) and the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, are indisputable. This study aimed to isolate and characterize beneficial bacteria isolated from the rhizosphere of pineapple from distinct stress-inducing habitats, including water excess-, herbicide-over-treated-, and pathogen-infected areas at PT Great Giant Foods located in Lampung, Indonesia. The isolated bacteria were screened based on IAA production and ACC deaminase activities. Six selected isolates produced IAA with concentrations of up to 36.93 mgL−1. The highest value belongs to Bacillus sp. NCTB5I, followed by Brevundimonas sp. CHTB 2C (13.13 mgL−1) and Pseudomonas sp. CHTB 5B (6.65 mgL−1). All isolates were detected with ACC deaminase activities with Brevundimonas sp. CHTJ 5H consuming 88% of ACC over 24 h, the highest among all. Brevundimonas sp. CHTB 2C was detected with the highest ACC deaminase activity with the value of 13,370 nm α-ketobutyrate mg−1h−1. In another experiment, it was revealed that all selected isolates promote soybean growth. These bacteria are potential to be developed in the future as bioagents to promote plant growth, especially under stressful environmental conditions.

Physiology and proteomics analyses reveal the regulatory mechanism of mepiquat chloride in soybean

Soybean is an important grain and oil crop cultivated worldwide. Mepiquat chloride (DPC), a plant growth regulator, is widely used in cotton planting; however, its application in soybean remains rarely studied. Herein, we explored DPC regulation in soybeans using morphology, physiology, and proteomics analyses. Morphological and physiological analyses showed that DPC significantly reduced the plant height and shoot dry weight, promoted the growth of lateral roots in a specific concentration range, increased the activities of the leaf protective enzymes (superoxide dismutase and catalase), and decreased and increased malondialdehyde and total flavonoid contents, respectively. Proteomic analysis of leaves treated with 100 mg/L DPC revealed that multiple proteins related to plant growth and stress resistance were regulated after treatment. The key proteins involved in photosynthesis and cell wall elongation in the two varieties of soybean were significantly downregulated and those related to promoting lateral root growth and stress resistance were significantly upregulated. Overall, DPC inhibited shoot growth and photosynthesis in soybean but promoted lateral root growth, enhanced protective enzyme activity, and improved the ability of plants to resist abiotic stress. This study preliminarily determined the suitable DPC concentration for soybean spraying and provided a theoretical basis for its rational application.

Plant growth regulators improve nitrogen metabolism, yield, and quality of soybean–rhizobia symbiosis

PurposeIn recent years, considerable research has been conducted on the use of plant growth regulators (PGRs) to improve crop yields. Large amounts of PGRs are applied to regulate crop growth. However, few studies have assessed the impact of PGRs, which leave soil residues, on soil microorganisms, especially rhizobia.MethodsIn this study, the influence of inoculation of soybean roots with Sinorhizobium fredii and Bradyrhizobium japonicum exposed to gibberellin A3 (GA3) and mepiquat chloride (MC) on nodule number, nitrogenase activity, and a symbiotic nitrogen fixation gene (fixA) expression was studied. The nitrate content, free amino acids, and nitrate reductase activity of the roots, and seed yield and quality of soybean were measured.ResultNodulation was promoted to some extent, whereas nitrogenase activity and fixA expression were inhibited to some extent by treatment with GA3; however, these effects were reversed by treatment with MC. In a pot experiment to study phenotypic characteristics, rhizobia treatment in combination with GA3 or MC significantly improved soybean yield and seed nitrogen content, and increased the root nitrate content, free amino acid content, and nitrate reductase activity.ConclusionThe results indicated that PGRs, which leave soil residues, have significant positive effects on the growth and activity of soybean and rhizobia.

Cytosolic Fructose-1,6-bisphosphate Aldolases Modulate Primary Metabolism and Phytohormone Homeostasis in Soybean

Fructose-1,6-bisphosphate aldolase (FBA) is an important catalytic enzyme in carbon metabolism and plays an important role in plant growth and development. Currently, the biological functions of FBA in soybean (Glycine max) remain unknown. In this study, we conducted research on FBA in soybean and identified 14 GmFBA genes. Among them, GmFBAc1 and GmFBAc2 are broadly expressed in different tissues. Double mutant lines of GmFBAc1 and GmFBAc2 were obtained by CRISPR-Cas9 gene editing technology. Compared with the wild type, the double-gene homozygous mutant gmfbac1gmfbac2 exhibited dwarf seedlings and narrow leaflets, indicating that GmFBAc1 and GmFBAc2 are critical for soybean growth and development. The gmfbac1gmfbac2 metabolomic analysis revealed that compared to the wild type, carbohydrate metabolism was reduced and amino acid metabolism was enhanced in gmfbac1gmfbac2 mutant leaves. Transcriptomic analysis showed that genes in IAA signaling and JA signaling were downregulated and upregulated, respectively. Our study demonstrates an important role of GmFBAc1 and GmFBAc2 in modulating carbon metabolism and phytohormone homeostasis.

“Alperujo” Compost Improves Nodulation and Symbiotic Nitrogen Fixation of Soybean Inoculated with Bradyrhizobium diazoefficiens

The utilization of compost to enhance plant productivity and symbiotic nitrogen fixation (SNF) has been recognized as an effective alternative to synthetic nitrogen fertilizers. This environmentally sustainable method is readily accessible to farmers. This study investigated the effect of olive pomace (“alperujo”, AL) compost on the nodulation and SNF of soybeans (Glycine max L.) and their natural symbiont (Bradyrhizobium diazoefficiens). For that, soybean plants were subjected to several doses of AL compost under controlled greenhouse conditions. At the end of the experiment, the dry weight of plant biomass (aerial part and roots), the number and fresh weight of nodules, and nitrogen and leghaemoglobin contents were analyzed. The application of AL compost significantly improved soybean growth, as demonstrated by an increase in both plant biomass and height. Furthermore, nodular leghaemoglobin content and nitrogen content were found to be enhanced by the addition of AL compost (7 and 40%, respectively), indicating an increase in nodule effectiveness and symbiotic efficiency. Our results provide clear evidence of the synergetic effect of AL compost on the soybean-B. diazoefficiens association, probably due to AL-compost improved soybean roots development, and rhizospheric organic matter and nutrients assimilation by rhizobia.