The Difference Of Cd Uptake And Tolerance Of Brassica Pekinensis And Brassica Chinensis'

Hydroponic and soil cultures were conducted to compare the cadmium tolerance and toxicity on the seedlings of B. pekinensis and B. chinensis. and the alleviation of GSH on cadmium toxicity of two species were studied. The B. pekinensis had a higher tolerance to cadmium toxicity and higher ability of cadmium uptake and accumulation in the shoots. Relativity, the Jiaobai No. 6 had a preferably endurances to cadmium and accumulation lowness cadmium in shoots. This species was likely to fitting grown on the cadmium-polluted soil.B. chinensis and B. pekinensis were obviously stressed by cadmium. The germination of seeds, the elongation of roots, and the chlorophyll content of leaves decreased, whereas the malondialdehyde (MDA) concentration in leaves of two species increased with the increasing cadmium concentration in the solution. These changes were more pronounce in B. chinensis than in B. pekinensisThe activities of superoxide dismutase (SOD) in leaves of B. chinensis and B. pekinensis increased in response to extending 50 umol/L cadmium supply from 0 to 7 days, while the activities peroxidase (POD) reduced at the first three days then tended to increase. The activities of peroxidase (POD) and superoxide dismutase (SOD) in leaves of B. chinensis and B. pekinensis increased in response to increasing Cd supply from 0 to 100 umol/L after 7 days treatment, but activities of SOD and SOD hadn't notably difference.Whether B. pekinensis or B. chinensis under cadmiun contained solution cultured, the cadmium contents in roots were marked higher than in shoots, and the majority of roots accumulated cadmium were combined in root cell walls. Comparing to B. pekinensis, B. chinensis cell wall had a higher adsorption ability to combine cadmium.The H+-ATPase activity of plasma membrane and tonoplast of B. pekinensis and B. chinensis were improved under 50 mol/L cadmium treated. When DNP, ATP synthesization inhibitor, added to 50 umol/L cadmium contained solution, the cadmium content in rootsand shoots of 5. pekinensis and B. chinensis were decreased, so we presumed that B. pekinensis and B. chinensis cadmium absorption and uptake were a energy depended initiative process.Glutathion (GSH) at 20 mg/L increased elongation of roots and the chlorophyll content of leaves and decreased the MDA concentration in leaves of two species under 50 umol/L Cd stressed. Comparing to B. pekinensis, the GSH effects of alleviation of cadmium toxicity were more evidenced. The result also showed that GSH increased the concentrations of NPT and Cd in the roots and decreased Cd transport from roots to shoots.