Effects of Calcium on the Alleviation of Cadmium Toxicity in Salix matsudana and Its Effects on Other Minerals

Effects of exogenous calcium (5 mmol/L) on accumulation of manganese, iron, copper and zinc in different organs (roots, new stems, leaves and old stems) of Salix matsudana Koidz exposed to 10 and 50 mu mol/L cadmium for 7, 14, 21 and 28 d were investigated in order to further understand calcium effects in alleviating cadmium toxicity. The results showed that cadmium could inhibit seedling growth of S. matsudana. 5 mmol/L calcium had a alleviating toxic effects on seedling growth. Results indicated that cadmium contents in the different organs increased significantly (P<0.05) with increasing cadmium concentration and prolonged duration of treatment. Cadmium concentrated mainly in the roots, and small amounts were transferred to shoots. 5 mmol/L calcium decreased the cadmium levels significantly (P<0.05) in the organs of S. matsudana exposed to all the cadmium concentrations used during the whole experiment. Data revealed that cadmium stress mainly affected the accumulation of manganese both in roots and shoots. Cadmium could induce the high levels of iron, zinc and copper in roots. Data also indicated that exogenous calcium could promote the absorption of copper, iron, zinc and manganese to different extent, suggesting that calcium has the alleviating effect on the toxicity of cadmium.