Abstract: Natural Nostoc flagelliforme has resistance to drought resistance,alkali,and high temperature.This study aimed to investigate the effects of saline alkali stress on N.flagelliforme cell.The modified BG-11 culture medium containing different concentrations (0,60,120,180,240 mmol/L) of saline-alkali was used to culture N.flagelliforme cell at 25 ℃,80 μmol/(m²·s).Electrolyte leakage,the activities of superoxide dismutase,the content of malondialdehyde,proline,soluble protein and trehalose were determined.The response of N.flagelliforme cell was analyzed under the stress.Under saline-alkali stress,along with the stress severity,N.flagelliforme cell increased relative plasmalemma permeability and MDA content.Superoxide dismutase activity and proline content increased at first and then decreased.The content of soluble protein gradually decreased,but trehalose content increased.Saline-alkali stress can induce structure and physiological response of N.flagelliforme cell,and it could resist mild injury caused by saline-alkali.

Key words: saline-alkali, Nostoc flagelliforme, physiological response