Uptake and Accumulation of Cadmium and Relative Gene Expression in Roots of Cd-resistant Salix matsudana Koidz

Salix matsudana is thought to be an ideal woody plant for use in phytoremediation programs in China. This study deals with the characterization of early responses to Cd in accumulation and its effects on other metals, and relative gene expression in roots exposed to 50 mu M of Cd for 1 to 24 hours. The Cd content in roots exposed to Cd for 1, 3, 6, 12, and 24 hours of treatment was approximately 280, 587, 605, 622, and 795 mu g/g DW, respectively. After 24 hours, Cd stress caused a decrease of iron (Fe) (34.1%), manganese (Mn) (60.1%), zinc (Zn) (40.7%) and calcium (Ca) (26.5%). After 24 hours of exposure, the relative expression of IRT1 was 6.7 times that of control treatment (P<0.05). A 160.8% increase was detected for the relative expression of NRAMP1 after exposure to Cd treatment for one hour. After three hours of stress, the expression of ZIP1 was 10 times that of control (P<0.05). The tolerance of plants to Cd involves gene expression, protein modification, and alterations in the coordination of major and secondary metabolites, which is a complex physiological and biochemical process.