The effects of salinity stress on Amorpha fruticosa Linn. seed germination, physiological and biochemical mechanisms

Abstract

Salinity stress is serious threat to crop productivity and globe food security. This study investigated the impact of NaCl (neutral salt) and basic salt (basic salt) on seed germination physiological and biochemical traits of Amorpha fruticosa. Salt stress had no significant effect on seed germination rate, however, alkali stress significantly decreased (p≤0.05) rate of germination. Both stresses also negatively affected the growth of radicle and germination (P <0.05), and the effect of alkali stress was greater than that of salt stress. The concentration of K+, Mg2+ and Na+/K+ in radicle and germ remained relatively stable, which was conducive to adapting to salt and alkali stress, but the concentration of K+, Mg2+, NO3-, H2PO4- and SO42- changed differently under salt and alkali stress. Tartaric acid was the main component of the 8 organic acids, and the accumulation changes of each component were different under salt stress and base stress. Tartaric acid was accumulated in large quantities under salt stress, and the accumulation of other acids (citric, malic, acetic, oxalic, formic and lactic acids) were markedly enhanced under alkali stress (P <0.05). Among the 16 free amino acids, arginine, alanine and threonine are the response solutes under salt stress, and glutamic acid and threonine are the response solutes under base stress. In In conclusion, proper concentration of salts can promote seed germination and radicle growth. Therefore, plant performance can be improved by soaking seeds in appropriate concentration of salts.