Responses of Carex dispalata to Pb~(2+) Stress and its Accumulation Ability

The response of growth characteristics,physiological indices and the Pb accumulation ability in Carex dispalata under Pb2+ stress were researched by water culture method.Different concentrations of Pb2+ were added to C.dispalata and measured physiochemical characteristics on the 1,5,9,13,17 d respectively.The results showed:(1)Plant height,length of longest root,new root,new tillers,fresh weight and the ratio of shoot to root dry weight were declined drastically with increasing Pb level.(2)Activities of antioxidant enzymes increased in the beginning and then decreased with extended time of exposure.With increasing Pb2+ stress concentrations,activity of CAT and POD were significantly increased,while activity of SOD increased in the beginning and then decreased.(3)MDA,Pro content and plasolemma permeability were significantly increased with increasing Pb concentrations and the prolongation of stress time.(4)Chlorophyll content was obviously increased in primary phase of Pb stress,but reduced gradually under longer stress time.(5)Pb content in C.dispalata was increased with the rising of Pb2+ concentrations and it withstands excess Pb with its higher Pb accumulation capacity in roots compared to the above-ground part.Pb average retention rate in root of C.dispalata was 84.62% and the biological transfer coefficient to Pb was less than one.The study indicated that C.dispalata could adapt and resist a certain extent of Pb toxicity.