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Background: Drought is the main restricted agent for growth and development of soybean and the physiological characteristics of different parts of soybean leaves changed significantly. Methods: To explore the impacts of drought stress on the physiological characteristics of leaves in different parts of soybean, in this study, Williams 82 was used as the experimental material and drought stress was simulated by a watering nutrient solution containing 10% PEG-6000. Under different treatment time conditions, the superoxide dismutase (SOD) activity and proline (Pro) content in different parts of soybean leaves were determined. Result: The results indicate that the SOD activity and Pro content in the upper and bottom leaves of soybean increased significantly under drought stress conditions and with the increase in drought stress time, the SOD activity in the upper and bottom leaves of soybean increased first and then declined and the content of Pro increased gradually. In general, soybean relief drought damage by increasing SOD activity and Pro content under drought stress. This study offered the theoretical foundation for exploring the mechanism of soybean drought resistance. [ABSTRACT FROM AUTHOR]

Background: Soybeans are the main sources of oil and protein for most of the global population. As the population grows, so does the demand for soybeans. However, drought is a major factor that limits soybean growth. Methods: The nitrogen content in different parts of the soybean under drought stress and rehydration was investigated using the soybean cultivars, HN44 and HN65, at different growth stages (vegetative growth, parallel period of vegetative growth and reproductive growth and reproductive growth). Result: During the vegetative growth stage, drought decreased the plant's nitrogen content. After rehydration, all the organs showed different degrees of compensatory effects. During the parallel period of vegetative and reproductive growth, drought decreased the nitrogen content of the leaves. After rehydration, the nitrogen content was partially restored. During the reproductive growth period, drought affected the translocation of nitrogen to the sink. After rehydration, the nitrogen content increased in the pods and decreased in other parts. In summary, rehydration after drought during the vegetative growth period of soybean can lead to nitrogen accumulation, but the reproductive growth phase differs from earlier; therefore, this period should avoid drought stress. [ABSTRACT FROM AUTHOR]

Background: As an important source of feed protein, soybean is involved in the processing industry, food industry and other fields. Therefore, in recent years, the demand for soybean has increased and soybean planting areas have also increased. However, frequent droughts have a serious impact on soybean yield. Methods: During the flowering period, the soybean plants were subjected to drought treatments of different degrees (0-7 days without water). The superoxide anion and proline contents in the leaves were determined. Then, fitting curves were drawn between the soil moisture content and the superoxide anion and proline contents. Result: The effects of different soil moisture contents on the superoxide anion and proline contents in soybean leaves and the correlation between these contents were analyzed. According to the fitting curves, with a decrease in the volumetric water content of soil, the superoxide anion and proline contents in soybean leaves increased. The superoxide anion contents in drought-tolerant cultivars were significantly lower than those in drought-sensitive cultivars and the proline contents were significantly higher in droughttolerant cultivars than those in drought-sensitive cultivars. The superoxide anion content in soybean leaves was positively correlated with the proline content in the soil volumetric water content range of 31.5% to 14.5%. [ABSTRACT FROM AUTHOR]

Background: The major medicinal alkaloids isolated from Uncaria rhynchophylla (gouteng in chinese) capsules are rhynchophylline (RIN) and isorhynchophylline (IRN). Extracts containing these terpene indole alkaloids (TIAs) can inhibit the formation and destabilize preformed fibrils of amyloid β protein (a pathological marker of Alzheimer’s disease), and have been shown to improve the cognitive function of mice with Alzheimer-like symptoms. The biosynthetic pathways of RIN and IRN are largely unknown. Results: In this study, RNA-sequencing of pooled Uncaria capsules RNA samples taken at three developmental stages that accumulate different amount of RIN and IRN was performed. More than 50 million high-quality reads from a cDNA library were generated and de novo assembled. Sequences for all of the known enzymes involved in TIAs synthesis were identified. Additionally, 193 cytochrome P450 (CYP450), 280 methyltransferase and 144 isomerase genes were identified, that are potential candidates for enzymes involved in RIN and IRN synthesis. Digital gene expression profile (DGE) analysis was performed on the three capsule developmental stages, and based on genes possessing expression profiles consistent with RIN and IRN levels; four CYP450s, three methyltransferases and three isomerases were identified as the candidates most likely to be involved in the later steps of RIN and IRN biosynthesis. Conclusion: A combination of de novo transcriptome assembly and DGE analysis was shown to be a powerful method for identifying genes encoding enzymes potentially involved in the biosynthesis of important secondary metabolites in a non-model plant. The transcriptome data from this study provides an important resource for understanding the formation of major bioactive constituents in the capsule extract from Uncaria, and provides information that may aid in metabolic engineering to increase yields of these important alkaloids. [ABSTRACT FROM AUTHOR]