Antioxidative characteristics of Reaumuria soongorica under drought stress.

Reaumuria soongorica(Pall.) Maxim.,an extreme xeric shrub and a dominant species in desert and semi-desert areas,was used to investigate the adaptive mechanism of antioxidative system in respond to desert condition.Lipid peroxidation and antioxidative characteristic were measured in 2-year-old plants exposed to different levels of drought stress.The concentration of H2O2 arose markedly with increasing drought stress,MDA content increased under drought stress and the total soluble protein content decreased strongly as drought stress increasing.Carotenoid and proline contents increased under drought stress;Superoxide dismutases(SOD) activity was elevated significantly with increasing drought stress,catalase(CAT) activity increased under drought stress and guaiacol-type peroxidase(POD) activity increased markedly under moderate drought stress and decreased significantly under severe drought stress.These results suggested that carotenoid,proline,SOD and CAT appear to function as important component of antioxidative defense system under drought stress in R.soongorica,and that POD doesn't remove H2O2 efficiently under severe drought stress.