Effects of exogenous indole-3-acetic acid on antioxidant enzyme activities and osmotic substance contents of lettuce under cadmium stress

Abstract

In plant growth and stress tolerance, indole-3-acetic acid (IAA) plays an important role. In this research, the effects of spraying different concentration (0, 25, 50, 100 and 200 μmol/L) of IAA on the antioxidant system in lettuce were investigated. The lettuce (Lactuca sativa) exposed to cadmium (Cd) exhibited the SOD, POD activities and MDA content obviously increased. Spraying exogenous IAA resulted that the CAT activity, soluble protein and proline content in shoots of lettuce increased compared with the Cd treatment alone, and MDA content with 50 μmol/L IAA was lowest. Therefore, spraying IAA effectively alleviated Cd toxicity and enhanced antioxidant system of lettuce, and the 100 μmol/L IAA was the optimal dose.