Tolerance And Phytoremediation Potential Of Three Legumes On Copper Tailings

Three leguminous herb species,Pisum sativum,Vigna unguiculata and Lablab purpureus were selected as experimental materials in the study of the effects of copper tailing stress on the growth,physiology and resistance and Cu tailings remediation potential of these species by pot culture.The main results are as follows:(1)The effects of different portions of Cu tailings on the growth and Cu accumulation of three legume plants by pot culture showed that three legume species had a certain ability to adapt to the Cu tailing,and P.sativum was the most tolerant species and the dry weights of above-and underground parts were higher than those cultivated in the soil.The ability of nitrogen fixation of three legume species were V.unguiculata > P.sativum > L.purpureus.The Cu concentrations in the above-and underground parts of three species treated with Cu tailings were higher than those of control(P<0.05).Most of Cu were accumulated in the underground parts of three legume species and the translocation factors of Cu were less than 1 in all treatments.(2)The effects of different portions of Cu tailings on the physiological indexes of three legume species were studied.The Results shows that MDA contents in aboveand underground parts of the P.sativum and the aboveground part of L.purpureus showed up first and then decreased,while,MDA contents in above-and underground parts of the V.unguiculata and the underground part of L.purpureus decreased gradually.The SOD and POD activity of the P.sativum and L.purpureus showed a decreasing trend except that the activity of SOD of P.sativum increased gradually and the CAT activity in the aboveground part of L.purpureus increased first and then decreased.All the AsA and GSH contents in the P.sativum and GSH in the L.purpureus were gradually decreased.However,the contents of GSH in V.unguiculata increased gradually as the portions of Cu tailings enhanced.(3)The effects of three legume species and Iris pseudacorus on plant growth,Cu accumulation and soil enzymes activities were studied.The results of the study showed that the growth and tolerance index: I.pseudacorus+ L.purpureus(I+H)> I.pseudacorus + P.sativum(I+P)> I.pseudacorus + V.unguiculata(I+V),I+P and I+H combination could promote plant Cu accumulation.In the urease activities: I+P>I+V>I+H;Phosphatase activities: I+V> other treatments;dehydrogenase activities: P and I+P were the best treatments;catalase activities: I+H>I+V>I+P,the electrical conductivity: I+H>I+V>I+P.The results indicated that I.pseudacorus and L.purpureus compound cultivation had the strongest ability to remediated Cu tailings.(4)The research of the effects of applying N,P,K and bacterial fertilizer in the Cu tailings on the growth and Cu accumulation of two legume species showed that N,P,K and bacterial fertilizer could promote the tolerance of V.unguiculata to Cu in tailings,while,applying N,P,K and bacterial fertilizer did not play a role to L.purpureus.Cu contents in V.unguiculata treated with N,P,K and bacterial fertilizer were significantly higher than those of control.However,Cu content in L.purpureus was only significantly higher than that of control by the treatment of bacterial fertilizer.The enrichment coefficients of Cu and Cu translocation factors of L.purpureus were higher than that of V.unguiculata.The research indicated that three legume species were able to grow in Cu tailing.Also these species could accumulate a certain amount of Cu and improve environment of Cu tailing.I.pseudacorus and L.purpureus compound planting was the strongest tolerant and remediated ability than other compound planting in Cu tailing.Applying N,P,K and bacterial fertilizer in the Cu tailings could play a role on improving the growth and Cu accumulation of V.Unguiculata.