Crucial variations in growth and ion homeostasis of Glycine gracilis seedlings under two types of salt stresses

Abstract

Based on Glycine gracilis growth and ion homeostasis testing, neutral salt (NS)and alkaline salt (AS) stress were characterized and the responses of G. gracilis were investigated.The injurious effects of AS on G. gracilis were obviously stronger than those of NS.The effects of both stresses on the Na + content and Na + /K + ratio were similar at low concentrations, but as the stress increased, the effects of a greater Na + content and Na + /K + ratio increased slowly under NS conditions, but sharply under AS. The roots of G. gracilis accumulated NO 3 -and H 2 PO 4 -, while the stems and leaves accumulated C 2 O 4 2 -and H 2 PO 4 -to maintain thein tracellular ion balance. The dominant intracellular anions in the stipes were NO 3 -and C 2 O 4 2 -under control conditions, and NO 3 -and H 2 PO 4 -under salt stress. With the increasing AS, the Cl -, NO 3 -and H 2 PO 4 -concentrations decreased, and G. gracilis might have increased SO 4 2 -and C 2 O 4 2 -levels to compensate for the shortage of inorganic anions. Under NS, the NO 3 -and C 2 O 4 2 -concentrations decreased, and G. gracilis might have increased Cl -, H 2 PO 4 -and SO 4 2