Effects of exogenous indole-3-acetic acid on antioxidant enzyme activities and osmotic substance contents of lettuce under cadmium stressLe Liang, Han Liu, Jing Lu, Xuemei Peng, Wanjia Tang and Yi TangE3S Web Conf., 136 (2019) 07001DOI: https://doi.org/10.1051/e3sconf/201913607001