Effects on antioxidant enzyme activities and osmolytes in Halocnemum strobilaceum under salt stress

摘要

The seedlings of Halocnermum strobilaceum were cultivated in 0.5%hoagland nutrient solution containing 0.0%,0.9%,2.7%and 5.4%of NaCl as well as composite salt(Na^+,Ca^(2+),K^+,Si^(4+)) for 20 days;all the contents are in weight ratio.Succulent level,inorganic ions(Na^+,K^+),organics such as betaine,proline,malondialdehyde,and antioxidant enzyme activities including superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),betaine aldehyde dehydrogenase(BADH) were measured to reveal its salt tolerance mechanism.When the composite salt concentration reaches 5.4%,SOD activity level,and MDA content is five times the control group;when it reaches 2.7%,the succulent level of seedlings,and the content of K^+ in roots is nearly two times the NaCl treatment;the dry weight is more than three times the control group;with the NaCl treatment,MDA is three times the contrast;when the salt concentration is 2.7%,POD reaches the maximum.Results indicate that Si^(4+),K^+,and Ca^(2+) from composite salt in the roots of H.strobilaceum improved the water-holding capacity.The activities of antioxidant enzyme were raised by the accumulation of proline and betaine,which increased the salt tolerance.The absorption of K^+ promoted the high ratio of K^+/Na^+ and alleviated the damage of cell membranes of H.strobilaceum,which is associated with osmotic contents such as betaine and proline.