Gas Exchange and Ionomic Changes in Wild and Cultivated Soybean Seedlings under Salt Stress

A comprehensive acquaintance of photosynthesis and ionic homeostasis are essential for improvement of salt tolerance in crops. However, gas exchange, ion homeostasis and their effects on metabolites in soybean under salt stress have not been fully investigated. In this study, wild and cultivated soybeans were used to explore gas exchange and ionomic profile changes in order to reveal the salt tolerance mechanism in wild soybean. Under neutral salt stress (NS), wild soybean increased the net photosynthetic rate (p(N)) and decreased Na+ and Cl- absorption and accumulated in the roots and reduced content in leaves than in cultivated soybean. Under alkaline salt stress, it inhibited the absorption of Cl- to adapt salt stress. During neutral salt stress in wild soybean, p(N) and carotenoids in leaves were positively correlated with fatty acid metabolism, but negatively correlated with amino acid, organic acid and antioxidant receiver operating characteristics (ROC) metabolisms in roots and Na+ and Cl- were negatively correlated with fatty acid metabolism in leaves and with TCA cycle in roots. Under alkaline salt stress, gas exchange was negatively correlated with amino acid metabolism in leaves, and with TCA cycle in roots and Na+ was positively correlated with amino acid metabolism. Results indicated the restricted accumulation of toxic ions, regulated absorption of nutrient elements, maintained gas exchange and then caused changes in small molecule metabolites pathway are possible reasons for salt tolerance in wild soybean. (C) 2019 Friends Science Publishers