DIFFERENCE OF CD ENRICHMENT AND TRANSPORT IN ALFALFA (MEDICAGO SATIVA L.) AND INDIAN MUSTARD (BRASSICA JUNCEA L.) AND CD CHEMICAL FORMS IN SOIL

In order to compare the application potential of alfalfa (Medicago sativa L.) and Indian mustard (Brassica juncea L.) on cadmium contaminated soil, difference in dry weight, Cd content and accumulation, transport and enrichment coefficient between alfalfa and Indian mustard were studied under different Cd levels (0, 75, 150, 300 and 600 mg•kg -1 ) using soil culture test.Also, Cd forms in soil were analyzed.The results showed that the dry weight of shoots and roots of alfalfa and Indian mustard decreased significantly (P < 0.05) with the increase of soil Cd levels, decreasing by 50.00-71.90%and 29.60-59.30%(alfalfa), 59.60-89.00%and 64.30-74.80%(Indian mustard) compared with the control.With the increase of soil Cd level, Cd concentration and Cd accumulation in shoots and roots of alfalfa and Indian mustard increased significantly (P < 0.05).At same soil Cd level, Cd concentration in shoots and roots was in order of alfalfa > Indian mustard, while Cd accumulation was in order of Indian mustard > alfalfa.At the soil Cd level of 75 mg•kg -1 , Cd concentration in shoots of alfalfa and Indian mustard exceeded the critical value of Cd hyperaccumulator (100 mg•kg -1 ), 356.463 mg•kg -1 and 308.735 mg•kg -1 respectively.The enrichment coefficient (BCF) of alfalfa and Indian mustard was above 1 under all Cd levels, and the transport coefficient (TF) and BCF was in order of Indian mustard > alfalfa.Based on comprehensive consideration of biomass, Cd accumulation, transport coefficient and enrichment coefficient, Indian mustard is more suitable as repair material for soil Cd pollution.