| Influence of combi ned pollution of Cu and Cd on the physiological and bioche mical characteristics of Brassica campestris ssp．chi nensis |
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| DOI：10.7606/j.issn.1000-7601.2008.04.27 |
| Key Words: Cu Cd combined pollution physiological and biochemical characteristics Brassicaca mpestris ssp．chinensis |
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| Abstract: |
| By pot experi ment the paper studied the effects of heavy metal pollution （Cu Cd and Cu ＋Cd） on the physiological and biochemical characteristics of plant （Brassica campestris ssp．chinensis）.The test soil contains one of five levels of Cu（0 25 50 100or 200mg／kg） and one of three levels of Cd（0 1 10mg／kg）. Harvest and analysis of leaf was after 40days.During the 40—day experi ment Brassica campestris ssp．chinensis survivedin the soil spiked up to 10mg／kg Cd and 200mg／kg Cu showing no visual heavy metal toxictiy sy mptoms such as necrosis and whitish-brown chlorosis.The biomass is negatively affected by the mixture of Cu and Cd. In the absence of Cd the relative plasmolemma per meability was sti mulated withincreasing Cu concentration but it was first inhibited and then sti mulated withincreasing concentration of Cu by the presence of Cd. Cu or Cd strongly reduced theleaf contents of chlorophyll （Chl） a and the ratio of Chl a and Chl b.The NRactivities did not vary withincreasing Cu concentration at Cd ＝0mg／kg.However the activities were first sti mulated and theninhibited withincreasing Cu concentration at Cd ＝1or 10mg／kg.The NRactivities were particularly increased at the concentration of Cu ＝200mg／kg.The sensibility of antioxidant enzy mes to increasing Cd and Cu concentration are different to enzy mes kinds.The SOD activity was first sti mulated and then inhibited with increasing concentration of Cu without Cd and that was sti mulated with increasing concentration of Cu at Cd ＝1or 10mg／kg.There were si milar responses in PODand SODactivities and the PODactivity was sti mulated with increasing concentration of Cd under same concentration of Cu.Increasing Cu concentration in soil significantly increased the activity of CAT and at the same Cu concentration the CAT activity was inhibited with increasing concentration of Cd. |