EFFECTS OF EXOGENOUS SALICYLIC ACID ON COPPER-MEDIATED MEMBRANE LIPID PEROXIDATION IN RICE SEEDLINGS

Copper is a major heavy metal contaminant, which has received increasing attentions over the last few decades. As a key signal transduction molecule, salicylic acid (SA) is involved in inducing plant tolerance to several stresses. In this study, the effects of salicylic acid on membrane lipid peroxidation in rice seedlings under copper stress were studied. The results showed that with the increasing of Cu2+ concentration, the membrane integrity in rice seedlings was destroyed and the electric conductivity was increased, meanwhile the MDA content rose significantly, which indicated that the membrane lipid peroxidation was intensified. With the addition of SA to the culture, the electric conductivity and MDA content both decreased, which illustrated that SA could protect the integrity of membrane system in some degree, and alleviate membrane lipid peroxidation in rice seedlings. Also, SA enhanced POD, CAT and SOD activity in rice seedlings under Cu stress, and reinforced the defense ability of rice seedlings against heavy metal stress.