Effects of exogenous indole acetic acid on growth and cadmium accumulation of Cyphomandra betacea seedlings

摘要

To identify whether the auxin treatment could promote the growth and reduce the cadmium (Cd) of fruit trees, the effects of different concentrations of indole acetic acid (IAA, one of the auxin) on the biomass, Cd content, photosynthetic pigment content, photosynthetic characteristics, antioxidant enzyme activity, and soluble sugars content in Cyphomandra betacea seedlings under Cd stress were studied. As the IAA concentration increased, the biomass, photosynthetic pigment content, soluble sugars content, and net photosynthetic rate of C. betacea seedlings tended to first increase and then decrease, with maximum values in the 60 mg/L IAA treatment. The Cd contents in different organs decreased and then increased with increasing IAA concentrations, with the minimum value in the 60 mg/L IAA treatment. Compared with the control, IAA treatments enhanced the activities of peroxidase and superoxide dismutase in the leaves of C. betacea seedlings and decreased the soluble protein content. Therefore, IAA treatments promoted growth, enhanced Cd resistance, and decreased the Cd content in C. betacea. The 60 mg/L IAA treatment was the most effective for promoting growth and decreasing the Cd content in C. betacea.