Soybean Cotyledons Research Articles

Measurements and predictions of seedling emergence forces

Quantifying seedling emergence pressure or forces (soil impedance to seedling) during the process of plant emergence is difficult in a practical setting. In this study, a mechanical seedling testing device was designed and calibrated to measure seedling emergence pressures experienced by conical or spherical mechanical seedling in soil with varying compaction levels. The data were analysed to generate regression models for predicting seedling emergence forces. Results showed a high correlation between the seedling emergence pressure and soil resistance. The resultant regression model produced a coefficient of determination (R2) of 0.99. After incorporating the morphological characteristics of soybean cotyledon and maize coleoptile into the model, the predicted seedling emergence forces increased with the soil compaction level. During the emergence process, average emergence force of the soybean seedlings was 11.8 N for the lowest compaction level and 28.5 N for the highest compaction level, and the corresponding values of the maize seedlings were 0.2 N and 0.6 N. In a non-compacted field plot, maize crop had a 95.4% emergence rate and soybean crop had 97.2%, whereas for a compacted plot, the corresponding emergence rates were decreased to 19.1% and 60.5%. Inferences made from the study provide information on the dynamics of soil-seedling interaction, which have important implications for managing soil compaction in crop production.

Enhanced lignin and cellulose metabolism promote cell wall synthesis and growth of wild soybean HRA under alkali stress.

Soil salinization adversely threatens plant survival and food production globally. The mobilization of storage reserves in cotyledons and establishment of the hypocotyl/root axis (HRA) structure and function are crucial to the growth of dicotyledonous plants during the post-germination growth period. Here, we report the adaptive mechanisms of wild and cultivated soybeans in response to alkali stress in soil during the post-germination growth period. Diferences in physiological parameters, microstructure, and the types, amounts and metabolic pathways of small molecule metabolites and gene expression were compared and multi-omics integration analysis was performed between wild and cultivated soybean under sufcient and artifcially simulated alkali stress during the post-germination growth period in this study. Structural analysis showed that the cell wall thickness of wild soybean under alkali stress increased, whereas cultivated soybeans were severely damaged. A comprehensive analysis of small molecule metabolites and gene expression revealed that protein breakdown in wild soybean cotyledons under alkali stress was enhanced, and transport of amino acids and sucrose increased. Additionally, lignin and cellulose synthesis in wild soybean HRA under alkali stress were enhanced. verall, protein decomposition and transport of amino acids and sucrose increased in wild soybean cotyledons under alkali stress, which in turn, promotes HRA growth. Similarly, lignin and cellulose synthesis in wild soybean HRA enhanced, which subsequently, enhanced cell wall synthesis, thereby maintaining the stability and functionality of HRA under alkali stress. This study presents important practical implications for the utilization of wild plant resources and sustainable development of agriculture.

UV-B Radiation Exhibited Tissue-Specific Regulation of Isoflavone Biosynthesis in Soybean Cell Suspension Cultures.

Isoflavones, a class of substances with high biological activity, are abundant in soybeans. This study investigated isoflavone biosynthesis in soybean cell suspension cultures under UV-B radiation. UV-B radiation enhanced the transcription level and activity of key enzymes involved in isoflavone synthesis in cell suspension cultures. As a result, the isoflavone contents significantly increased by 19.80% and 91.21% in hypocotyl and cotyledon suspension cultures compared with the control, respectively. Meanwhile, a significant difference was observed in the composition of isoflavones between soybean hypocotyl and cotyledon suspension cultures. Genistin was only detected in hypocotyl suspension cultures, whereas glycitin, daidzein, and genistein accumulated in cotyledon suspension cultures. Therefore, UV-B radiation exhibited tissue-specific regulation of isoflavone biosynthesis in soybean cell suspension cultures. The combination of suspension cultures and abiotic stress provides a novel technological approach to isoflavone accumulation.

Automatic Localization of Soybean Seedlings Based on Crop Signaling and Multi-View Imaging.

Soybean is grown worldwide for its high protein and oil content. Weeds compete fiercely for resources, which affects soybean yields. Because of the progressive enhancement of weed resistance to herbicides and the quickly increasing cost of manual weeding, mechanical weed control is becoming the preferred method of weed control. Mechanical weed control finds it difficult to remove intra-row weeds due to the lack of rapid and precise weed/soybean detection and location technology. Rhodamine B (Rh-B) is a systemic crop compound that can be absorbed by soybeans which fluoresces under a specific excitation light. The purpose of this study is to combine systemic crop compounds and computer vision technology for the identification and localization of soybeans in the field. The fluorescence distribution properties of systemic crop compounds in soybeans and their effects on plant growth were explored. The fluorescence was mainly concentrated in soybean cotyledons treated with Rh-B. After a comparison of soybean seedlings treated with nine groups of rhodamine B solutions at different concentrations ranging from 0 to 1440 ppm, the soybeans treated with 180 ppm Rh-B for 24 h received the recommended dosage, resulting in significant fluorescence that did not affect crop growth. Increasing the Rh-B solutions reduced crop biomass, while prolonged treatment times reduced seed germination. The fluorescence produced lasted for 20 days, ensuring a stable signal in the early stages of growth. Additionally, a precise inter-row soybean plant location system based on a fluorescence imaging system with a 96.7% identification accuracy, determined on 300 datasets, was proposed. This article further confirms the potential of crop signaling technology to assist machines in achieving crop identification and localization in the field.

Exploring the impact of sulfocalcic solution and water glass on the synthesis of phytoalexins and antifungal activity against Cladosporium cladosporioides

The passion fruit production in Brazil stands out as an activity of significant interest, especially for small-scale farmers, due to the short cycle of the crop, high economic returns, and wide demand in the consumer market, encompassing both fresh consumption and industrial processing. However, despite these attractions, the crop faces considerable challenges due to its notable susceptibility to diseases. In this context, this study was conducted with the purpose of evaluating the effectiveness of sulfocalcic solution and water glass in two distinct aspects: (i) in the in vitro control of Cladosporium cladosporioides, the causal agent of Passion Fruit Scab; and (ii) in the induction of phytoalexin synthesis in soybean cotyledons and bean hypocotyls. Four distinct treatments were implemented: T1 as a control, T2 with water glass (1.25%), T3 with sulfocalcic solution (3.03%), and T4 with sulfocalcic solution (0.5%). Results revealed that the 3.03% sulfocalcic solution demonstrated significant efficacy in controlling mycelial growth, followed by the treatment with the same substance at 0.5%. Treatments 3 and 4 were equally effective in inhibiting germination and sporulation, reaching approximately 90%, while water glass showed no efficacy in the conducted tests. Regarding the induction of phytoalexins, none of the treatments resulted in the accumulation of these compounds in bean hypocotyls; however, the 3.03% sulfocalcic solution induced synthesis in soybean cotyledons. These findings underscore the potential of sulfocalcic solution as an effective control agent against C. cladosporioides.

Overexpression of R2R3-MYB IbMYB1a induces anthocyanin pigmentation in soybean cotyledon.

This is the first report showing anthocyanin accumulation in the soybean cotyledon via genetic transformation of a single gene. Soybean [Glycine max (L.) Merrill] contains valuable components, including anthocyanins. To enhance anthocyanin production in Korean soybean Kwangankong, we utilized the R2R3-type MYB gene (IbMYB1a), known for inducing anthocyanin pigmentation in Arabidopsis. This gene was incorporated into constructs using two promoters: the CaMV 35S promoter (P35S) and the β-conglycinin promoter (Pβ-con). Kwangankong was transformed using Agrobacterium, and the presence of IbMYB1a and Bar transgenes in T0 plants was confirmed through polymerase chain reaction (PCR), followed by gene expression validation. Visual inspection revealed that one P35S:IbMYB1a and three Pβ-con:IbMYB1a lines displayed seed color change. Pβ-con:IbMYB1a T1 seeds accumulated anthocyanins in cotyledon outer layers, whereas P35S:IbMYB1a and non-transgenic black soybean (Cheongja 5 and Seum) accumulated anthocyanins in the seed coat. During the germination and growth phase, T1 seedlings from Pβ-con:IbMYB1a lines exhibited anthocyanin pigmentation in cotyledons for up to 1month without growth aberrations. High-performance liquid chromatography confirmed cyanidin-3-O-glucoside as the major anthocyanin in the Pβ-con:IbMYB1a line (#3). We analyzed the expression patterns of anthocyanin biosynthesis genes, chalcone synthase 7,8, chalcone isomerase 1A, flavanone 3-hydroxylase, flavanone 3'-hydroxylase, dihydroflavanol reductase 1, dihydroflavanol reductase 2, anthocyanidin synthase 2, anthocyanidin synthase 3, and UDP glucose flavonoid 3-O-glucosyltransferase in transgenic and control Kwangankong and black soybean (Cheongja 5 and Seum) seeds using quantitative real-time PCR. We conclude that the induction of gene expression in transgenic plants in comparison with Kwangankong was attributable to IbMYB1a transformation. Notably, flavanone 3-hydroxylase, flavanone 3'-hydroxylase, and dihydroflavanol reductase 1 were abundantly expressed in black soybean seed coat, distinguishing them from transgenic cotyledons.

An ex vitro hairy root system from petioles of detached soybeanleaves for in planta screening of target genes and CRISPR strategies associated with nematode bioassays.

The ex vitro hairy root system from petioles of detached soybeanleaves allows the functional validation of genes using classical transgenesis and CRISPR strategies (e.g., sgRNA validation, gene activation) associated with nematode bioassays. Agrobacterium rhizogenes-mediated root transformation has been widely used in soybean for the functional validation of target genes in classical transgenesis and single-guide RNA (sgRNA) in CRISPR-based technologies. Initial data showed that in vitro hairy root induction from soybean cotyledons and hypocotyls were not the most suitable strategies for simultaneous performing genetic studies and nematode bioassays. Therefore, an ex vitro hairy root system was developed for in planta screening of target molecules during soybean parasitism by root-knot nematodes (RKNs). Applying this method, hairy roots were successfully induced by A. rhizogenes from petioles of detached soybeanleaves. The soybean GmPR10 and GmGST genes were then constitutively overexpressed in both soybean hairy roots and tobacco plants, showing a reduction in the number of Meloidogyne incognita-induced galls of up to 41% and 39%, respectively. In addition, this system was evaluated for upregulation of the endogenous GmExpA and GmExpLB genes by CRISPR/dCas9, showing high levels of gene activation and reductions in gall number of up to 58.7% and 67.4%, respectively. Furthermore, morphological and histological analyses of the gallsweresuccessfully performed. These collective data validate the ex vitro hairy root system for screening target genes, using classical overexpression and CRISPR approaches, directly in soybean in a simple manner and associated with nematode bioassays. This system can also be used in other root pathosystems for analyses of gene function and studies of parasite interactions with plants, as well as for other purposes such as studies of root biology and promoter characterization.

Soybean LEAFY COTYLEDON 1: A Key Target for Genetic Enhancement of Oil Biosynthesis

Soybean is an important oilseed crop that is used as a feed for livestock and has several industrial uses. Lipid biosynthesis and accumulation primarily occur during seed development in plants. This process is regulated by several transcription factors and interconnected biochemical pathways. This study investigated the role of glycine max LEAFY COTYLEDON 1 (GmLEC1) in soybean seed development and the accumulation of storage reserves. The overexpression of GmLEC1 significantly increased the amount of triacylglycerol (TAG) in transgenic Arabidopsis seeds compared to the wild-type and an atlec1 mutant. Similarly, the high expression of GmLEC1 led to a 12% increase in TAG content in transgenic soybean hairy roots compared to the control. GmLEC1 also altered the fatty acid composition in transgenic Arabidopsis seeds and soybean hairy roots. Additionally, the overexpression of GmLEC1 resulted in a reduction in starch accumulation in seeds and vegetative tissues, as well as changes in cotyledon and seed morphology. The cotyledons of the atlec1 mutant displayed abnormal trichome development, and the seeds were smaller and less tolerant to desiccation. A complementation assay in Arabidopsis restored normal cotyledon phenotype and seed size. The main downstream targets of LEC1 are GL2 and WRI1, which were found to participate in fatty acid biosynthesis and trichome formation through the regulation of phytohormones and various transcription factors involved in seed development and maturation. The findings of this study suggest that GmLEC1 controls seed development and regulates the accumulation of seed storage compounds. Furthermore, these results demonstrate that GmLEC1 could be a reliable target for the genetic improvement of oil biosynthesis in soybean.

Evaluation of the contents and ratios of five fractionated proteins to elucidate the protein composition in soybean seeds

AbstractSelecting suitable soybean cultivars is important for food processing and exploring their endowment with desirable physiological functions. We applied the fractionation method previously established to compare soy protein composition among cultivars to promote such a selection. More than 95% of the proteins in soybean cotyledons were extracted from 13 soybean cultivars using a high‐concentration salt solution. The extracted proteins were fractionated into five fractions, namely oil body‐associated protein (OBAP), polar lipid‐associated protein (PLAP), globulins (11S and 7S), and whey by centrifugation after tuning the solubility behavior of the proteins with various solutions. Protein species in each fraction were analyzed by SDS‐PAGE. Protein content in the total extract and five fractions was quantified to characterize the protein composition of soybean cultivars. The correlation between the protein content of each fraction and the total protein in cotyledon was investigated. A strong positive correlation was found only for the 11S fraction (r = 0.82), followed by a positive correlation in the 7S fraction (r = 0.65). Thus, we surmised that the increased protein content in soybean was due to increased globulin content. Furthermore, the calculation of the average ratio of protein content in each fraction indicated the globulin fraction (7S and 11S) to be 52%, the lipophilic protein fraction (OBAP and PLAP) to be 33%, and the whey fraction to be 13%. The preparation method employed in this study is a promising tool for efficiently comparing the protein composition of soybean cultivars to evaluate the potential use of cultivars for food production.

Construction and Functional Evaluation of CRISPR/Cas9 Multiple Knockout Vectors of the FAD2 Gene Family

Soybean oil is a traditional edible oil. Increasing the oleic acid content is an important direction of soybean breeding. The soybean FAD2 family consists of seven genes that regulate how oleic acid is converted into linoleic acid. Five genes of the soybean FAD2 gene family, GmFAD2-1B, GmFAD2-1A, GmFAD2-2B, GmFAD2-2C, and GmFAD2-2D, were taken as target genes in this study. Firstly, a multivalent CRISPR/Cas9 gene-editing vector was constructed to regulate FAD2 gene expression. Multiple knockout vectors were inserted into the soybean varieties JN38, T6098, and T7010 using Agrobacterium-mediated soybean cotyledon transformation. The functional analysis, agronomic character analysis, and comparison of the mutant lines of the offspring of different genotypes indicated that the JN38 mutant was significantly taller in terms of plant height than the receptor JN38. The fatty acid content of the three groups showed the same trend. The fatty acid contents of mutant plants were higher than those of recipient plants, and the linoleic acid contents of mutant plants were lower than those of recipient plants. The best-performing among the three groups was the JN38 mutant, whose oleic acid content increased from 18.58% to 54.07% and whose linoleic acid content decreased from 57.79% to 26.17%. In conclusion, the knockout expression of multiple FAD2 genes increased the soybean oleic acid content and decreased the linoleic acid content in different receptors.

Correlation of Processing Techniques with Some Quality Indexes of Soy-Akamu Prepared with Yellow Maize, Sprouted and Un-Sprouted Soybean

Akamu or ogi is a commonly relished gruel when prepared with hot water by the sick, recovering patients and infants in Nigeria. It is nutritionally deficient due to inevitable processing losses which called for fortification with soybean (soy-akamu or soy-ogi). Soy-akanu was prepared from steeped yellow maize, sprouted and un-sprouted soybean cotyledons using different processing techniques. Proximate, micronutrients and functional properties were evaluated with standard analytical methods. The results showed that proximate composition of soy-akamu produced from dried steeped maize and sprouted soybean cotyledons had higher protein (63.20%), fibre (0.33%), ash (1.11%), energy (384.28 Kcal) and least moisture content (4.53%). The paste samples had respective values of 0.77, 3.06%; 0.00, 0.00%; 0.71, 1.02%; 29.86, 3303%; 143.50, 145.37 mg/100g, and 64 and 36-64-76%. Dried soy-akamu also had the highest calcium (41.18, iron (0.99), phosphorous (0.27), .zinc (48.02), potassium (0.45), vitamin C (24.60) and least in magnesium (0.07 mg/100g) content. The paste samples had respective values of 40.13, 41.14; 0.86, 0.92; 0.39, 0.41; 0.39, 0.41; 20.46, 23.65 mg/100g with respective magnesium (0.10-0.12) and phosphorous ( 0.25, 2.21 mg/100g) contents. Different processing techniques had significant (p<0.05) variations in proximate, micronutrient and functional properties of the soy-akamu and also their major sources of nutrient losses.

Integrated metabolomic and transcriptomic strategies to reveal alkali-resistance mechanisms in wild soybean during post-germination growth stage.

The keys to alkali-stress resistance of barren-tolerant wild soybean lay in enhanced reutilization of reserves in cotyledons as well as improved antioxidant protection and organic acid accumulation in young roots. Soil alkalization of farmlands is increasingly serious, adversely restricting crop growth and endangering food security. Here, based on integrated analysis of transcriptomics and metabolomics, we systematically investigated changes in cotyledon weight and young root growth in response to alkali stress in two ecotypes of wild soybean after germination to reveal alkali-resistance mechanisms in barren-tolerant wild soybean. Compared with barren-tolerant wild soybean, the dry weight of common wild soybean cotyledons under alkali stress decreased slowly and the length of young roots shortened. In barren-tolerant wild soybean, nitrogen-transport amino acids asparagine and glutamate decreased in cotyledons but increased in young roots, and nitrogen-compound transporter genes and genes involved in asparagine metabolism were significantly up-regulated in both cotyledons and young roots. Moreover, isocitric, succinic, and L-malic acids involved in the glyoxylate cycle significantly accumulated and the malate synthetase gene was up-regulated in barren-tolerant wild soybean cotyledons. In barren-tolerant wild soybean young roots, glutamate and glycine related to glutathione metabolism increased significantly and the glutathione reductase gene was up-regulated. Pyruvic acid and citric acid involved in pyruvate-citrate metabolism increased distinctly and genes encoding pyruvate decarboxylase and citrate synthetase were up-regulated. Integrated analysis showed that the keys to alkali-stress resistance of barren-tolerant wild soybean lay in enhanced protein decomposition, amino acid transport, and lipolysis in cotyledons as well as improved antioxidant protection and organic acid accumulation in young roots. This study provides new ideas for the exploitation and utilization of wild soybean resources.

Field Availability and Avoidance of Imidacloprid-Treated Soybean Seeds and Cotyledons by Birds.

Treated seeds and their cotyledons can present a toxicological risk to seed-eating birds. To assess whether avoidance behavior limits exposure and consequently the risk to birds, three fields were sown with soybeans. Half of the surface of each field was sown with seeds treated with 42 g/100 kg seed of insecticide imidacloprid (T plot, treated) and the other half with seeds without imidacloprid (C plot, control). Unburied seeds were surveyed in C and T plots at 12 and 48 h post-sowing. Damaged seedlings were surveyed in C and T plots at 12 days post-sowing. The abundance and richness of birds was surveyed at the field level (without distinguishing between C and T plots) before, during, and after sowing, and 12 days post-sowing. Unburied seed density was higher in the headlands of the T plots than in the C plots, but did not differ between 12 and 48 h. The damage to cotyledons of seedlings was 15.4% higher in C plots than in T plots. The abundance and richness/ha of birds that eat seeds and cotyledons were lower after sowing, indicating a deterrent effect on birds by sowing imidacloprid-treated seeds. Although the variation in seed density over time does not allow solid conclusions to be drawn about the avoidance of seeds treated by birds, the seedling results suggest an aversive effect of imidacloprid-treated soybeans on birds. The dominant species was the eared dove (Zenaida auriculata), whose risk of acute poisoning by imidacloprid in soybean seeds and cotyledons was low, according to its toxicity exposure ratio, foraged area of concern, and foraged time of concern. Environ Toxicol Chem 2023;42:1049-1060. © 2023 SETAC.

UV-B radiation enhances isoflavone accumulation and antioxidant capacity of soybean calluses.

Isoflavones are a class of flavonoids that belong to a large family of polyphenols and synthesized predominantly in legume, and they play important roles including acting as antioxidant, preventing osteoporosis, reducing the risk of atherosclerosis, and protecting against cardiovascular disease. This study focused on the accumulation and synthetic metabolism of isoflavone in soybean hypocotyl and cotyledon calluses under UV-B radiation. The results showed that UV-B radiation significantly up-regulated the gene expression of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), chalcone ketone synthase (CHS), chalcone isomerase (CHI), and isoflavone synthase (IFS), and enhanced their activity in soybean hypocotyl and cotyledon calluses. As a result, isoflavones content increased by 21.23 and 21.75% in soybean hypocotyl and cotyledon calluses, respectively. Among the isoflavones produced, malonyldaidzin was the dominant one in hypocotyl callus, while malonylglycitin and daidzein were the main isoflavones in cotyledon calluses. This study revealed that UV-B radiation induced isoflavone accumulation in soybean calluses, which could be an efficient strategy to improve the nutritional value of food and produce high levels of bioactive secondary metabolites.

Bio-priming with Trichoderma Enhanced Faster Reserve Mobilization in Germinating Soybean Cotyledons under Graded Macronutrients

Bio-priming with Trichoderma Enhanced Faster Reserve Mobilization in Germinating Soybean Cotyledons under Graded Macronutrients

Wild soybean salt tolerance metabolic model: Assessment of storage protein mobilization in cotyledons and C/N balance in the hypocotyl/root axis.

Salt stress has become one of the main factors limiting crop yield in recent years. The post-germinative growth is most sensitive to salt stress in soybean. In this study, cultivated and wild soybeans were used for an integrated metabonomics and transcriptomics analysis to determine whether wild soybean can resist salt stress by maintaining the mobilization of stored substances in cotyledons and the balance of carbon and nitrogen in the hypocotyl/root axis (HRA). Compared with wild soybean, the growth of cultivated soybean was significantly inhibited during the post-germinative growth period under salt stress. Integrating analysis found that the breakdown products of proteins, such as glutamate, glutamic acid, aspartic acid, and asparagine, increased significantly in wild soybean cotyledons. Asparagine synthase and fumarate hydratase genes and genes encoding HSP20 family proteins were specifically upregulated. In wild soybean HRA, levels of glutamic acid, aspartic acid, asparagine, citric acid, and succinic acid increased significantly, and the glutamate decarboxylase gene and the gene encoding carbonic anhydrase in nitrogen metabolism were significantly upregulated. The metabolic model indicated that wild soybean enhanced the decomposition of stored proteins and the transport of amino acids to the HRA in cotyledons and the GABA shunt to maintain carbon and nitrogen balance in the HRA to resist salt stress. This study provided a theoretical basis for cultivating salt-tolerant soybean varieties and opened opportunities for the development of sustainable agricultural practices.

Application of Iron Oxide Nanoparticles in the Surface-Assisted Laser Desorption and Ionization–Mass Spectrometry of Small-Molecule Compounds

Iron oxide nanoparticles were applied to the surface-assisted laser desorption and ionization–mass spectrometry (SALDI–MS) of small-molecule compounds, such as oligosaccharides, phytohormones, flavonoids, triglycerides, phospholipids, and amino acids. The spatial distribution of small-molecule compounds in soybean was further studied by using imaging mass spectrometry. After different preparation methods were compared, iron oxide nanoparticles calcined at 300 °C were selected. Results showed that in SALDI–MS analysis, iron oxide nanoparticles were characterized by good stability and low background noise. Analysis was performed in the positive ion mode at the laser energy of 70% with the average spectrum accumulated 30 times. The results showed that iron oxide nanoparticles had good repeatability and sensitivity in the analysis of the abovementioned small-molecule compounds. Four samples, namely, sucrose, abscisic acid, DL-aspartic acid, and 1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine, were analyzed via SALDI–MS. The spot-to-spot repeatability RSD was less than 2.8%, and the interpoint repeatability RSD was less than 5.2%. The linear correlation coefficient of the four samples was R2 > 0.993 within the concentration range of 0.05–1.0 mg/mL. On the basis of these results, the distribution of small-molecule components in soybean cotyledon, radicle, and germ was analyzed through SALDI–MSI.

A Model for Identifying Soybean Growth Periods Based on Multi-Source Sensors and Improved Convolutional Neural Network

The identification of soybean growth periods is the key to timely take field management measures, which plays an important role in improving yield. In order to realize the discrimination of soybean growth periods under complex environments in the field quickly and accurately, a model for identifying soybean growth periods based on multi-source sensors and improved convolutional neural network was proposed. The AlexNet structure was improved by adjusting the number of fully connected layer 1 and fully connected layer 2 neurons to 1024 and 256. The model was optimized through the hyperparameters combination experiment and the classification experiment of different types of image datasets. The discrimination of soybean emergence (VE), cotyledon (VC), and first node (V1) stages was achieved. The experimental results showed that after improving the fully connected layers, the average classification accuracy of the model was 99.58%, the average loss was 0.0132, and the running time was 0.41 s/step under the optimal combination of hyperparameters. At around 20 iterations, the performances began to converge and were all superior to the baseline model. Field validation trials were conducted applying the model, and the classification accuracy was 90.81% in VE, 91.82% in VC, and 92.56% in V1, with an average classification accuracy of 91.73%, and single image recognition time was about 21.9 ms. It can meet the demand for the identification of soybean growth periods based on smart phone and unmanned aerial vehicle (UAV) remote sensing, and provide technical support for the identification of soybean growth periods with different resolutions from different sensors.

Hypothesis of the formation of bacterial blights on secondary moistened cotyledons of soybean and other leguminous crops

The article examines cotyledonous bacterial blight – a possible causes of the decrease in seed sowing quality of leguminous crops. The article presents the hypothesis that there is another cause for the development of cotyledonous necroses, regardless of species, variety, and crop’s cultivation area. The secondary (rain) moistening of mature seeds leads to the development of cotyledonous necroses and a decrease in seed germination of soybean, white bean, chickpea, white lupin, and blue lupin due to the subsequent necrotization of over-moistened areas of cotyledon tissues. The secondary moistening of mature seeds can lead to the development of cotyledon necrosis and a decrease in germination of soybean seeds, white beans, chickpeas, white lupin and blue lupin due to subsequent necrotization of waterlogged areas of cotyledon tissues. The symptoms of cotyledon necrosis development during secondary moistening of mature seeds and cotyledonous bacterial blights are almost identical in all leguminous crops. Bacterial pathogens of various species and families are isolated on the dead areas of cotyledons. This fact can be explained by the repeated saprophytic infection of cotyledon sites.

Avoidance of neonicotinoid-treated seeds and cotyledons by captive eared doves (Zenaida auriculata, Columbidae)

Farmland birds can be exposed to neonicotinoids through the ingestion of treated unburied seeds and cotyledons. The aim of this study was to evaluate the avoidance of sorghum with imidacloprid, clothianidin or thiamethoxam, soybean with imidacloprid, and soybean cotyledons with imidacloprid or thiamethoxam on eared doves (Zenaida auriculata). Doves were fed with test food (untreated and neonicotinoid-treated sorghum, soybean or soybean cotyledons) and maintenance food (seed mix) for 3–5 days to study the repellency (primary repellency and conditioned aversion) and anorexia caused by neonicotinoid-treated food, followed by a 7-day period on maintenance food to study the persistence of the anorexic effect after neonicotinoid exposure. Immediately afterward, the same doves were exposed to treated test food during a second period of 3–5 days to study the potential reinforcement of food avoidance. Finally, doves were fed with untreated test food to test the capacity of the pesticide to induce conditioned food aversion against untreated food in subsequent encounters. Intoxication signs and differences of body weight were determined. With sorghum, the three neonicotinoids produced a decrease in the consumption of treated seeds by >97% compared to control birds. However, this was not enough to prevent the death of 3/8 and 1/8 of the doves exposed to imidacloprid and clothianidin, respectively. Anorexia was clearly observed with neonicotinoid-treated sorghum. The birds did not avoid the untreated sorghum after exposure to the treated sorghum, indicating that avoidance is not generalized to the type of food without an associated sensory cue. The results obtained with soybean seeds and cotyledons were less conclusive because captive doves hardly consumed these foods, even without neonicotinoid treatment. The avoidance of sorghum seeds treated with neonicotinoids was insufficient to prevent poisoning and death of eared doves.