Effects of different salt-alkaline stress on seed germination and physiological characteristics of Hedysarum polybotrys

Abstract

In order to get the method for improving the salt resistance of Hedysarum polybotrys seeds and seedlings under different salt-alkaline stress, the seed germination and physiological characteristics of H. polybotrys seedlings were studied. Several physiological indexes of H. polybotrys seeds under different salt-alkaline stress, such as the germination vigor, germination rate, relative germination rate, relative salt damage rate were measured. And others indexes of the seedlings like chlorophyll contents, soluble protein contents, the permeability of plasmalemma, the activities of POD and SOD were also measured. Different salt-alkaline stress decreased the germination rate, vigor of germinate, germination index, while relative salt damage rate increased. With the increased salt-alkaline concentration, the adverse effects became more obvious. The strength of the salts: Na2CO3 > Na2SO4 > NaCl. With the increase of the salt-alkaline concentration, the chlorophyll contents and the soluble protein contents decreased, but the permeability of plasmalemma increased. The change trend of SOD and POD activity was similar, it is increased firstly, and then decreased as the stress intensity extended, the most significant increase of Na2SO4 and Na2CO3 in the concentration of salt-alkaline was 25 mmol x L(-1), but NaCl was 50 mmol x L(-1). The seeds and seedlings inhibition of the salts was Na2CO3 > Na2SO4 > NaCl.