Abstract
Effects of water stress and foliar boron (FB) application on soybean (Glycine max (L) Merr.) seed composition and nitrogen metabolism have not been well investigated. Therefore, the objective of this study was to investigate the effects of water stress and FB on seed protein, oil, fatty acids, nitrate reductase activity (NRA), and nitrogenase activity (NA). A repeated greenhouse experiment was conducted where one set of soybean plants were subjected to water stress (WS), and the other set was watered (W). Foliar boron (B) was applied at rate of 0.45 kg·ha-1. Treatments were watered-plants with no FB (W), watered-plants with FB (WB), water-stress plants with no FB (WS), and water-stress plants with FB (WSB). The results showed that seed protein and oil percentage were significantly (P 15N/ 14N and 13C/12C natural abundance were altered between watered-and watered-stressed plants. These results suggest that water stress and FB can influence seed composition, and nitrogen metabolism, and 15N/14N and 13C/12C ratios, reflecting environmental and metabolic changes in carbon and nitrogen fixation pathways. Lack of B translocation from leaves to seed under water stress may suggest a possible mechanism of limited B translocation under water stress. These findings may be beneficial to breeders to select for B translocation efficiency under drought conditions. Altered 15N/14N and 13C/12C under water stress can be used as a tool to select for drought tolerance using N and C isotopes in the breeding programs.
Highlights
Soybean is a major crop in the world, and soybean seed is a major source of protein and oil
These results suggest that water stress and foliar boron (FB) can influence seed composition, and nitrogen metabolism, and 15N/14N and 13C/12C ratios, reflecting environmental and metabolic changes in carbon and nitrogen fixation pathways
Seed (Figure 1(a)) and nodule (Figure 1(b)) weights and Nitrogen Metabolism in Soybean were higher in W and with FB (WB), with the highest weight observed in WB treatment
Summary
Soybean is a major crop in the world, and soybean seed is a major source of protein and oil. The quality of soybean seed is determined by the content and composition of protein, oil, and fatty acids. Soybean seed protein ranges from 34 to 57% of total seed weight, with a mean of 42%, and oil content ranges from 8.3 to 28%, with a mean of 19.5% [1]. The concentration of saturated fatty acids in soybean seed oil ranges from 10% to 12% palmitic acid (C16:0), and 2.2 to 7.2% stearic acid (C18:0) [2]. The mean concentration of unsaturated fatty acids in soybean seed oil is 24% oleic acid (C18:1), 54% linoleic acid (C18:2), and 8.0% linolenic acid (C18:3) [3]. Higher oleic acid and lower linolenic acid are desirable traits for oil stability and long-term shelf storage for industrial and processing purposes, but higher linolenic acids (essential polyunsaturated) are desirable for human nutrition. The food industry is becoming increasingly interested in producing soybean seed with a AJPS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
