| With the rapid development of economy,the eutrophication,heavy metal pollution and antibiotic pollution of water bodies caused by human activities had become the focus of the society.Contaminants in water could threaten human health through food chain transmission and others directly or indirectly.Therefore,the work of water pollution restoration was urgent and important..Salix matsudana Koidz was used as the research object.The effects of combined stress on the growth characteristics,physiological indexes and accumulation of pollutants were explored with hydroponically growing S.matsudana cuttings.1.The effects of heavy metal pollution on the growth characteristics,physiological indexes and heavy metals accumulation were explored under eutrophication conditions with hydroponically growing S.matsudana cuttings.The results showed that under 50 ?mol L-1 Cu treatment,the cutting growth was significantly depressed and its physiological response was induced,with decreasing dry weight,RGR,Ti and content of photosynthetic pigment,as well as increasing MDA content and POD activity.The damage of 50 ?mol L-1 Cu to S.matsudana was more serious than 50?mol L-1 Zn.With the increase of N and P concentration,biomass increased while MDA content and POD activity decreased.Eutrophication could alleviate the damage of heavy metals to S.matsudana.Cu and Zn were mainly accumulated in the root of S.matsudana cuttings.With the increase of N and P concentration,Cu and Zn accumulated in the root of S.matsudana cuttings significantly decreased.Accumulation of Zn in the root of S.matsudana cuttings increased when TF and the transport of Zn to the shoot part depressed by Cu.Under the combinations of N and P(N0P0,N1.5P0.18 and N,5P1.8,the same below),TF of Zn under ZnCu treatments significantly reduced by 62.80%,57.05%and 77.86%(P<0.05)compared with Zn,respectively.However,the accumulation of Cu in the root of S.matsudana cuttings reduced while TF and the transport of Cu to the shoot promoted by Zn.Under three combinations of N and P,TF of Cu under ZnCu treatments significantly increased by 25.96%,62.87%and 42.86%(P<0.05)compared with Cu,respectively.The transport of Zn to the shoot part significantly increased with the increase of N and P concentration,but the transport of Cu had no significant change.Compared with the Zn treatment,TF of Zn promoted by 45.60%and 247.31%(P<0.05)under N1.5P0.18Zn and N15P1.8Zn treatments.2.The effects of CTC and Zn combined stress on the growth characteristics,physiological indexes and CTC accumulation were explored with hydroponically growing S.matsudana cuttings.The results showed that the dry weight of shoots and roots decreased with the increase of Zn concentration,but POD activity in leaf and root increased significantly(P<0.05)under the same CTC concentration.The dry weight of roots showed a downward trend with the increase of CTC concentration under the same Zn concentration.Compared with CTC0 treatment,RGR of shoots and roots increased under CTC1 treatment,but decreased significantly under CTC5 and CTC10 treatments(P<0.05).Compared with CTC0 treatment,content of MDA in leaf and root had no significant improvement under CTC1 treatment,but content of MDA and POD activity increased significantly under CTC5 and CTC10 treatments(P<0.05).CTC mainly accumulated in root of S.matsudana.CTC accumulated in root increased significantly with the increase of CTC concentration(P<0.05)under the same Zn concentration.Zn significantly increased the enrichment of CTC in root(P<0.05).3.The effects of CTC and Cu combined stress on the growth characteristics,physiological indexes and CTC accumulation were explored with hydroponically growing S.matsudana cuttings.The results showed that root activity,the dry weight of shoots and roots decreased significantly with the increase of Cu concentration,but POD activity in leaf and root increased significantly(P<0.05),and MDA content in leaf and root showed an overall upward trend under the same CTC concentration.The CTC1 treatment could improve the dry weight of root to some extent.When the CTC concentration was the same(CTCO and CTC1),the content of chlorophyll a,b and carotenoid decreased with the increase of Cu concentration.Compared with CTCO treatment,activity of POD and SOD in leaf and root had no significant improvement under CTC1 treatment,but activity of POD increased significantly under CTC5 and CTC10 treatments(P<0.05).CTC mainly accumulated in root of S.matsudana.CTC accumulated in root increased significantly with the increase of CTC concentration(P<0.05)under the same Cu concentration.Cu significantly increased the enrichment of CTC in root(P<0.05).In summary,S.matsudana has strong ability to accumulate Cu and Zn.With the increase of N and P concentration,toxicity of heavy metals to S.matsudana could be alleviated,accumulation of Cu and Zn in root reduced when the transport of Zn to shoot part promoted.The low concentration CTC had no significant toxic effect on S.matsudana,but the toxic effect was significant at high concentrations.CTC was mainly accumulated in the root of S.matsudana,and the presence of Zn or Cu could significantly increase the enrichment of CTC. |
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