Cotyledons Of Soybean Seeds Research Articles

Primary cause of cotyledonous bacterial blight on soybean

One of the main causes of the worldwide decrease of sowing quality of soybean seeds is a cotyledonous bacterial blight in the form of necrotic decaying spots on the outer or inner side of cotyledons. We hypothesize that there is a primary non-bacterial cause for the development of necrotic spots on cotyledons of soybean seeds. We carried out the research in 2016-2020 at V.S. Pustovoit All-Russian Research Institute of Oil Crops on soybean seeds. Cotyledonous bacterial blight is never recorded on immature seeds of healthy soybean plants at the stages of a complete filling and the beginning of physiological maturation. But the secondary (rain) moistening of mature seeds on unharvested plants leads to the development of cotyledonous necroses and a decrease of soybean seed germination due to the subsequent necrotization of over-moistened and repeatedly dried tissues of cotyledons. The physiological mechanism of cotyledon necrosis formation is based on the secondary moistening of individual areas or whole mature seeds to a critical moisture level that initiates nucleic acid synthesis. This irreversibly activates the cell division processes of the over-moistened areas of cotyledons. Subsequent drying of seeds with over-moistened areas of cotyledons leads to their necrosis. The isolation of bacterial pathogens of various species and families in the necrotic areas of cotyledons can be explained by the secondary saprophytic infection of the over-moistened tissues already dead after secondary drying.

A Soluble Polysaccharide from Soybean Seeds and its Components.

Information on the characteristics of soybean polysaccharides is limited. This study was undertaken to purify and characterize a polysaccharide in mature soybean seeds (Glycine max (L.) Merr. cv. Akishirome). A soluble polysaccharide, A1-β, was extracted from the cotyledons of soybean seeds with water and purified by Bio-Gel A150m and DEAE-Sephacel column chromatography. The homogeneity of A1-β was confirmed by ultracentrifugal and electrophoretic analyses, and its molecular weight was ca. 2×106. The major components of A1-β were arabinose and galactose in the molar ratio of 2:3. Other components were rhamnose, fucose, xylose, mannose, glucose, mannuronic acid, galacturonic acid and glucuronic acid. These results indicate that A1-β may be a polysaccharide that has never been reported in soybean seeds.

Characterization of proteins released from legume seeds in hot water

When immersed in water at 50–60°, mature soybean seeds release a large amount of protein. The major protein released was basic 7S globulin (Bg), which is present in the cotyledons of soybean seeds. The released Bg consisted of the 27 000 and 16 000 subunits which were linked by disulphide bonding and glycosylated. The released Bg exhibited an identical structure with the mature Bg which was synthesized in the normal developing seeds. Proteins like Bg were also found to be released into hot water from the seeds of legume species such as azuki-bean, cowpea, mung-bean and winged-bean. Besides Bg and Bg-like proteins, a few proteins including the 9000 hydrophobic protein in soybean, ubiquitin in cowpea and mung-bean, and Kunitz trypsin inhibitor in winged-bean, were released from the seeds in hot water.

The guard mother cell dormancy of soybean cotyledon

The cotyledons of soybean seeds serve both as a food source and a photosynthetic organs for the early development of soybean seedlings. The development of the stomata of cotyledons should be important and related to the food source utilization and the mechanism of photosynthesis. During the study of the development of the cotyledon stomata of soybean seeds, a phenomenon was observed on the upper epidermal layer of the cotyledon, we call it. “the dormancy of the guard mother cell”, which is not reported in the literature available to us.Soybean seeds were soaked, planted and sampled at 24, 48, and 72 hours after planting. The upper epidermal layers were stripped with a sharp razor blade, and processed for observation with Hitachi S-2300 scanning electron microscope.

Electropherogram Patterns of Proteins of Embryo Axes, Cotyledons and Protein Bodies of Soybean Seeds

Summary Protein spectra of embryo axes (EA) protein bodies (PB) and cotyledons of soybean seeds were analysed by electrophoresis in polyacrylamide gel. Trypsin inhibitor was not detected in PB. Protease activity in PB was twice higher and more than two-fold lower in comparison with cotyledons and EA, respectively. Phosphatase activity was the highest in the embryo axes.

Occurrence of mRNA for storage protein in dry soybean seeds.

Poly(A)-containing RNA has been isolated from the cotyledons of soybean seeds by adsorption on a poly(U)-Sepharose column. Approximately 0.15% of the total soybean RNA applied bound to the column. The bound RNA (poly(A)-containing RNA) was shown to be mRNA by its ability to serve as template in a cell-free system derived from wheat germ. Poly(A)-containing RNA was polydisperse, migrating from approximately 50,000 to 700,000 daltons with a mean of 150,000 daltons in polyacrylamide gel electrophoresis. The size of the poly(A) portion of this RNA was in the range of 55 to 290 nucleotides. The adenylic acid content of the presumed poly(A) fragment was about 95%. The radioactive products of translation directed by the poly(A)-containing RNA in the wheat germ cell-free system were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by immunoprecipitation using antisera against beta-conglycinin and glycinin. The results of this investigation show that mRNAs for the subunit proteins of the major components of a soybean storage protein exist in the poly(A)-containing RNA preparation obtained from the cotyledons of dry soybean seeds.

Fatty acid distribution in glycolipids and phospholipids in cotyledons of germinating soybeans.

This investigation was conducted to observe changes in the fatty acid distributions of glycolipids (GL) and phospholipids (PL) in cotyledons of soybean seeds which were germinated either in the dark or the light at 28°C for 8 days. The GL isolated from the total lipids of cotyledons at different germinating stages were : acyl sterylglycoside (ASG), monogalactosyl diglyceride (MGD), digalactosyl diglyceride (DGD) and sulfolipid (SL). The PL isolated from the same total lipids as described above were : diphosphatidyl glycerol (DPG), phosphatidic acid (PA), phosphatidyl ethanolamine (PE), phosphatidyl glycerol (PG), phosphatidyl choline (PC) and phosphatidyl inositol (PI).During germination of soybean seeds, the content of linoleic and linolenic acids in MGD or DGD was markedly higher than that of the other GL. The positional distribution of fatty acids in PE, PC and PI was shown in all PL, in which saturated fatty acids, especially palmitic acid, were highly concentrated in position 1 and unsaturated fatty ...

Changes in glycolipid and phospholipid compositions in cotyledons of germinating soybeans.

This investigation was conducted to observe changes in the compositions of fatty acids, glycolipids (GL) and phospholipids (PL) in cotyledons of soybean seeds which were germinated either in the dark or the light at 28°C for 8 days. The patterns of changes in lipid composition depended on the germinating conditions tested. In general, non-polar lipids were metabolized at a faster rate than polar lipids. Changes in lipid contents in cotyledons were also observed more clearly with the polar lipids than with the non-polar ones, especially in the light-grown seedlings. The major component of lipid, GL in chloroplasts, appeared rapidly at an earlier stage in the cotyledons of light-grown seedlings. During germination of soybean seeds, acyl sterylglucoside in cotyledons decreased rapidly, but monogalactosyl diglyceride and digalactosyl diglyceride (DGD) increased in the light-grown seedlings, whereas sterylglucoside and DGD increased in the dark-grown seedlings. The major PL present immediately after immersion were phosphatidyl ethanolamine (PE), phosphatidyl choline (PC) and phosphatidyl inositol (PI). During germination under both conditions, light and dark, PE in cotyledons decreased with PC or PI, while phosphatidic acid increased rapidly, and phosphatidyl glycerol and diphosphatidyl glycerol also increased slightly. These changes in glycolipid and phospholipid compositions during germination seem to occur from the formation of photosynthetic tissues and the metabolic interconversion of phospholipids.

Effect of pH on the extraction of polyadenylic acid-containing RNA from soybean seeds.

The effect of pH in the SDS-phenol extraction step on the extractability, messenger activity and the composition of RNA species of the poly (A)-containing RNA from the cotyledons of soybean seeds was examined. The amount of total RNA extracted from the cotyledons was almost the same under neutral and alkaline pH. However the content of the poly (A)-containing RNA was higher in the preparation obtained under alkaline pH than neutral pH. higher in the preparation obtained under alkaline pH than neutral pH. This result shows that the poly (A)-containing RNA was efficiently extracted from soybean seeds under alkaline pH. In a mRNA-dependent cell-free system derived from E. coli, there was no significant difference in the messenger activity of the poly (A)-containing RNA between the two preparations. The patterns of the poly (A)-containing RNAs of the two preparations were very similar to one another in the case of dry soybean seeds, while there was slight difference in the case of green soybean seeds. The pol...

Ribonucleic acids with messenger activities in the cotyledons of soybean seeds.

Ribonucleic acids from the cotyledons of soybean seeds (H-RNA) stimulated the amino acid incorporation in a cell-free system prepared from soybean seedlings at a concentration of 5 mm magnesium acetate. In a reticulocyte cell-free system H-RNA stimulated the amino acid incorporation at a concentration of 10 mm Mg2+, but not at 4.3 mm Mg2+ Aurintricarboxylate, an inhibitor for the initiation of protein synthesis, inhibited the H-RNA and TMV-RNA-stimulated amino acid incorporation by about 90% and 70% at a concentration of 50 μm in E. coli and soybean seedling systems, respectively. When the H-RNA preparation was passed through a Millipore filter, about 1% of the charged RNA was retained on the filter. Chromatography on plain cellulose of H-RNA resulted in slight enrichment of an RNA fraction with the characteristics of mRNA.