The Influence Of Cu And Cd Stress On The Growth Of Brassica Campestris L. And The Biological Effectiveness

In recent years, the farmland soil pollution is more and more serious, heavy metal pollution as one of the main pollution, serious damage to the plant growth, thus that endanger human body health. So under heavy metal pollution, the research of the extent of tolerance,the response of the various physiological indicators of plants and the heavy metal poisoning mechanism is particularly important. Although people have related study, but the impacts of different heavy metal stress on the different plants are different, the interaction in different growth periods is also different, so in this study, through the outdoor simulation potted experiment, the effects of different concentrations of Cu, Cd single and combined stress on the rape at different growth stages were studied, and discussed the migration of heavy metals in the soil, the conclusions are as follows:The growth of rape is promoted under low concentration treatment (Cu≤100 mg·kg-1; Cd≤ 3mg·kg-1), and is inhibited under high Cu concentration, and the higher the concentration of Cu and Cd, the largest inhibiting effects. Under combined pollution, there is a significant synergy on promoting rape growth under low combined concentration (Cu\Cd≤200mg·kg-1\3mg·kg-1), and high treatment concentrations have significantly antagonistic effect.Under low treatment concentrations, the enhancement at Cu stress on synthesis of chlorophyll is stronger than Cd; Cu and Cu all can promote the synthesis of Vc, but different tolerance performance; High concentration processing, stressing effect of Cd on the synthesis of Vc and chlorophyll is strongest. Under combined concentration processing, overall the chlorophyll synthesis are affected.under the stress of Cu, the resistance of POD is increased, the activity of CAT weakened obviously, SOD activity is little inhibited; The activity of three kinds of antioxidant enzymes first increased after the drop under Cd stress with the increase of the concentration. Under combined concentration processing, there is an antagonism effect on inhibition of SOD and CAT activity at low concentrations treatments (50mg·kg-1 mg·kg-1 and ≤100 mg·kg-1, respectively), the activity of POD of rape under all the treatment is inhibited.Due to the different resistance ability, the accumulation ability of rape on Cu and Cd in soil is different. Under the experimental conditions, the accumulation action of rape on Cu is stronger than that on Cd. Under single metal pollution, the enrichment decreased with the increasing of treatment concentration; but under combined concentration processing, the accumulation action on Cd increased sharply at the combined concertration of 5 mg·kg-1.Under single and combined stress of Cu, the main form absorbed by rape at four stages are EXC, CAB, EXC, EXC and CAB, FMO, FMO, EXC, respectively, and Under single and combined stress of Cd, those are EXC, EXC, CAB, CAB and CAB, FMO, EXC, CAB.