Effects of Lead Stress on Physiological Characteristics and Pb~(2+) Uptake of Cynodon dactylon

In order to elucidate the toxic mechanism of C.dactylon under lead(Pb2+)stress and the underlying mechanism involved in phytoremediation of heavy metal contaminated soil and water,Pb(NO3)2was added into Hoagland solution to imitate Pb2+polluted water environment and the effects on antioxidant system,chlorophyll content and the capacity for Pb2+accumulation in resisting Pb2+stress in C.dactylon were studied by water culture method.The results showed that the activities of SOD,CAT and chlorophyll content went obviously up at the beginning of lead stress(Pb2+20mg/L),the maximum were 361.78 U/g FW,215.16 U/(g· min)and 2.99 mg/L respectively;but they decreased as the quantity of lead increasing and the stress time extending.The minimum were 152.87U/g FW,162.12U/(g·min)and 1.44 mg/L respectively;The activity of POD of C.dactylon showed an up trend with increasing Pb2+concentration,the maximum was 291.12 U/g FW.Pb2+was mainly distributed in the roots of C.dactylon,followed by the stems.This investigation also showed that C.dactylon could decrease the content of Pb2+in polluted water,and the C.dactylon was a good plant species for the water ecosystem restoration.