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CORESTA Congress, Shanghai, 2008, AP 36

Cadmium and lead immobilization by amendments in polluted soils and effects on tobacco (Nicotiana tabacum) growth

HU Zhongsheng; ZHAO Qibo; ZHU Weixing; WANG Hongwu; LIU Yanjie; ZHANG Ying; WANG Guangzhi; CAO Zhihong
Jiangsu Branch of China Tobacco Industry Corporation, R&D Center, Nanjing, China

To decrease potential harm of heavy metals in tobaccos to human beings from the source, a pot experiment was conducted to investigate the effects of amendments on Cadmium (Cd) and Lead (Pb) immobilization and growth of tobacco in soils. The analysis performed on the data showed that DTPA-extractable Cd and Pb in soils were reduced to different degrees by the three amendments used compared to the control treatment. Under the effects of the amendments, treatment with amendments decreased Cd and Pb concentrations in roots and leaves of tobacco. Higher transportation index of Cd in the leaves as compared to Pb indicated that it was of importance to reduce Cd uptake by tobacco. DTPA-extractable Cd and Pb in soils were positively correlated to the metal concentrations in tobacco leaves suggesting that DTPA-extractable Cd and Pb in soils may be a feasible method to estimate Cd and Pb availability to tobacco plants and the reduction in leaf Cd and Pb concentration was due to a reduction in metal availability to tobacco. Experimental results showed that upward trends in leaf SPAD value was observed when plants were grown in soils with all various amendments with the increase. The additions of amendments caused a increase in root length, plus an accompanying increase in the shoot length, leaf area and leaf dry weight, indicating significant protection against Cd and Pb toxicity. Furthermore, the higher dose of amendments used, the better positive effects were obtained. In general, three amendments were the good amendments that improved tobacco health, quality and yield.