Physiological Response of an Alkali Resistant Halophyte Kochia sieversiana to Salt and Alkali Stresses

A natural halophyte Kochia sieversiana was taken as the material.Using simulative ecological conditions,the seedlings of K.sieversiana were treated under the salt-stress conditions of 0～480 mmol·L-1 mixed neutral salts NaCl and Na_2SO_4(molar ratio=1∶1),and the alkali-stress conditions of 0～480 mmol·L-1 mixed alkaline salts NaHCO_3 and Na_2CO_3(molar ratio=1∶1).The relative growth rate(RGR) and other physiological index of stressed seedlings were determined to analyze K.sieversiana abilities and features of anti-salt and anti-alkali in order to investigate its physiological basis of ecological location.The results showed that K.sieversiana possessed of not only great salt resistance but also great alkali resistance.It still lived and maintained a slow growth under the salt stress of 480 mmol·L-1 and the alkali stress of 400 mmol·L-1.The salt-stress at low concentration(80 mmol·L-1) did not inhibit its growth but stimulated its growth.Seeing from the strain indexes of RGR,chlorophyl content and malondialdehyde(MDA) content,under the same salt concentration,effect of the alkali-stress on the seedlings of K.sieversiana was more intensity than of the salt-stress.The strain responses of K.sieversiana to alkali-stress were more obvious than to salt-stress on average.