Polyamine is a kind of important antioxidants which have close relationship with the tolerance of plant under stress. S. bigelovii were chosen as experimental materials in this paper. The effects of exogenous spermidine on ultrastructure of chloroplast, polyamine content in leaves and chloroplasts and photosynthetic efficiency of S. bigelovii under salt stress were investigated. The results are as follows:
First, seedlings of S. bigelovii were treated with different concentrations of NaCl (0, 100,200,30...