Wedelia trilobata's response to heavy metals and heavy metal absorption and enrichment in its body with sludge as a part of growth substrate
Phytoremediation is a good method for solving more and more prominent heavy metal problems.However,plant's response to heavy metals and heavy metals accumulation in the plant's body are the basic scien-tific issues in this field.In order to reveal the response of Wedelia trilobata to heavy metals and its accumulation effect in sludge,a soil experiment was designed and carried out.The physiological indexes in the leaves of W.tri-lobata,including chlorophyll content,peroxidase(POD) activity,and superoxide dismutase(SOD) activity after planting in different ratios of sludge(containing heavy metals) to sandy soil for three,four,five and six months,were detected respectively.The metals content(Cd,Cr,Mn,Ni,Pb,Cu,Zn) in the leaves,roots,and stems of W.trilobata after planting in different ratios of the above growth substrate for six months,were also detected re-spectively.The results showed that the chlorophyll content in the leaves of W.trilobata significantly(P0.05) as-cended with the increase of sludge proportion;the POD activity and SOD activity significantly(P0.05) changed with the increase of sludge proportion,and both significantly(P0.05) decreased after growth in the growth sub-strate;it also showed that the content of Ni,Cu and Cr in the leaves of W.trilobata were higher when grown in substrate with higher proportional sludge added(20% and 40% sludge).Our experiment suggest that the sludge is helpful to increase chlorophyll content in the leaves of W.trilobata,which has strong tolerance to sludge heavy metals,and it is a hyperaccumulator of Ni,Cu and Cr.