Effects of exogenous indole-3-acetic acid on the photosynthesis characteristics of lettuce under cadmium stress

IAA (indole-3-acetic acid), can regulate plant growth and development, and it can involve in regulation of abiotic stresses. In the present study, the effects of spraying different concentrations (0, 25, 50, 100 and 200 μmol/L) of IAA on the photosynthesis physiology in lettuce were investigated. The lettuce (Lactuca sativa ) exposed to cadmium (Cd) exhibited a substantial change in photosynthetic pigment content and photosynthetic parameters. Spraying exogenous IAA resulted in alleviating the inhibitory of Cd toxicity to lettuce. The photosynthetic pigment content in shoot of lettuce increased by spraying with IAA compared with the Cd treatment alone. Cd stress caused reductions (P ) in Pn and Ls, respectively, whereas Gs, Ci, and Tr were increased, compared with the control. Spraying exogenous IAA resulted that the Pn increased and the Ls, Gs, Ci, Tr showed different trend. Therefore, spraying IAA effectively changed the photosynthetic pigment contents and photosynthesis parameters in lettuce.