Impacts of Cu and Zn pollution on rape(Brassica chinensis L.) growth and its accumulation effect of heavy metals in paddy soil

Effects of Cu and Zn on growth,activity of SOD,proline,soluble sugar of rape(Brassica chinensis L.) and its accumulation characteristics of heavy metals were studied by cultivation experiments.The results showed that biomasses、physiological and biochemical index and SOD activity were impacted by Cu,Zn treatments.Dry weight of rape and SOD activity increased with low Cu,Zn concentration treatment.With increasing Cu,Zn concentration,the plant growth slowed down,the biomass and SOD activity decreased.When the concentration of Cu reached 1000 mg?kg-1,dry weight of rape and SOD activity decreased by 36.79%,66.67% compared with the control,respectively.When the concentration of Zu reached 3000 mg?kg-1,dry weight of rape and SOD activity decreased by 55.21%,82.05% compared with the control,respectively.When treated with Cu,the content of proline decreased gradually,the content of soluble sugar firstly increased and then decreased;when the concentration of Cu reached 1000 mg?kg-1,the contents of proline and soluble sugar decreased by 56.55%,37.66% compared with the control,respectively.Under Zn pollution,the contents of proline and soluble sugar increased firstly and then decreased similarly.When the concentration of Zn reached 3000 mg?kg-1,the contents of proline and soluble sugar decreased by 36.32%,36.55% compared with the control,respectively.Treated by Cu and Zn,the Cu,Zn content of leaves and root increased obviously,furthermore,the accumulation of heavy metals in root was particularly obvious.When the concentration of Cu and Zn was 1000 mg?kg-1,the content of Cu in shoot and root were 57.6 mg?kg-1 and 424.162 mg?kg-1,respectively;the content of Zn in shoot and root were 240 mg?kg-1 and 608.54 mg?kg-1,respectively.Contrast to Zn,Cu mainly accumulated in the root of rape.The results indicated that Zn more easily accumulated in the aboveground part of rape,and entered the food chain,compared to Cu.The experiments showed that physiology,biochemistry and nourishment of rape were affected by the accumulation of Cu and Zn obviously.