interspecific differences and accumulative characteristics of cadmium and lead about seven alfalfa(medicago sativa l) cultivars in a lead-zinc mine of yunnan, china

For studying the interspecific differences and accumulation features of cadmium(Cd) and lead(Pb) about different alfalfa(Medicago Sativa L) varieties, greenhouse experiments were carried out in a lead-zinc mine of Yunnan and the indexes including plant height, biomass, content and accumulation of Cd and Pb, enrichment coefficient and transfer coefficient were measured. The results showed that from the enrichment coefficient, the variety having the strongest Cd accumulation capacity was "Youke", its Cd enrichment coefficient, Cd content of shoot, Cd accumulation of shoot were respectively 0.054, 0.22 mg·kg^-1 and 40.58 μg·m^-2 and were higher respectively by 145%, 100% and 145% than that of the weakest varieties "WL525HQ" in anthesis(120 day). The svariety having the strongest Pb accumulation capacity was "Guochan", its Pb enrichment coefficient, Pb content of shoot, Pb accumulation of shoot were respctively 0.035, 2.67 mg·kg^-1 and 282.2 μg·m^-2 and were higher respectively by 52%, 53% and 10% than that of the weakest varieties "WL525HQ" in anthesis(120 day). From transfer coefficient, most of cultivars used in experiments had a certain capacity for transfering Cd and Pb from root to shoot. The variety having the strongest Cd transfer capacity was "Sandeli", its Cd transfer coefficient was 1.545 and was higher by 72% than that of the weakest varieties "Guochan" in anthesis(120 day). The variety having the strongest Pb transfer capacity was "Guochan", its Pb transfer coefficient was 2.048 and was higher by 71% than that of the weakest varieties "Duoye" in anthesis(120 day). In conclusions the inerspecific differences of Cd and Pb accumulative characteristics were existed among alfalfa cultivars used in the experiments, Based on metal content in shoot "Youke" and "Guochan" could be considered as Cd and Pb high accumulation cultivar respectively, whereas "Sijiwang" and "WL525HQ" could be considered as Cd and Pb low accumulation cultivar respectively.