Celastrus (celastrus Orbiculatus Thunb.), The Response Mechanism Of The Heavy Metals Lead, Copper Explore

With the development of the society and economy,the pollution of heavy metal is more and more serious.A lot of heavy metals,such as Cu,Pb,Zn,As come into environment,and led to serious air and soil pollution.Ecological reclamation of wasteland has been one of the urgent tasks we are facing nowadays.Kinds of the reclamation methods of pollution soil had been tested worldwide so far.However,compared with physical and chemical ways of reclamation, biological and ecological reclamation was a prior one due to its lower cost,effectual outcome and no secondary pollution.The key step for the ecological reclamation was the selection of heavy metal-resistant plants.Research on the damage of heavy mentals and the resistence of plants to heavy mentals can apply theoretic derection for selecting soil reclamation plants.In this paper,Oriental bittersweet(Celastrus orbiculatus Thunb.)were used as material, which was adopted widely to landscaping and had strong ecological adaptability.The toxic effects of Pb²⁺,Cu²⁺ treatment on Celastrus orbiculatus were investigated by simulating test and analysing physiological and biochemical indexes.The results as follows:(1) The germination of seeds were promoted by low concentration of Cu and Pb.However, with the increase of concentration of Cu and Pb,Germination of seeds were inhibited obviously.(2) It was shown that the growth of Celastrus orbiculatus seedling growing in quartz sand was improved by low concentration of Cu/Pb.The fresh/dry weight,the contents of water,the above-ground height of the seedling were all higher than control plants.However,with the increase of concentration of Cu and Pb,the seedling grew slowly compare with control plants, the biomass,the water content and content of leaf pigments decreased drastically too.(3)Under the stress of Pb²⁺ and Cu²⁺,a series of change occurred in the substance and protective enzymes related with the stress.Fouthermore,all indexes demonstrated a correlation between the does and effect.The higher pollution concentration and the longer the pollution time, the more serious the damage was.Proline,soluble protein and soluble saccharide content increased first and deceased afterwards with enhancing treatment concentration and time.While malondialdehyde(MDA) content increased persistently and the permeability of cell membrane(CMP) and increased obviously during the course.It showed that lipid peroxidation, which was considered an indication of oxidative stress in plants,could be induced via free radicals that were generated as a result of heavy metal toxicity in plant.Lipid peroxidation can degrade biological membrane making them susceptible to oxidative damage.Under low concentration stress and short time treatment,the protective systems was activitaed in Celastrus orbiculatus Thunb,and the activities of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) were induced in high level to eliminate ractive oxygen species(ROS).While with more serious damage to Celastrus orbiculatus Thunb,the defensive system of cells could not protect cells effectively and MDA content increased evidently.Disorder of ROS elimination system results to inordinate physiological metabolism in seedling,which speed up senescence and death of plants.