| In this paper,based on the early research of our team in mountain putuo Lead-Zinc mine of Hanyuan country in Ya’an,taking the Carex putuoshanensis sp. which is a new species in the Carex genus as the research object.Study the single and combined Pb-Zn treatment on the impact of C. putuoshanensis sp. through the sand culture experiment,including growth conditions,Lead and Zinc enrichment characteristics and physiological metabolism. And discusses the physiological mechanism of C. putuoshanensis sp. under the stress of Lead-Zinc. The main results are summarized as follows:(1)Under the sand culture experiment,C putuoshanensis sp. had a very high tolerance to Lead,but low to Zinc. In a single Lead treatment(200-600mg/L), the plant height, root length and biomass were increased.When Lead concentration was 600 mg/L, the biomass reached a maximum value of 14.49g/pot. While the Lead concentration increased to 800mg/L-2000mg/L,the plant height,root length and biomass showed a decreasing trend,but showed no obvious harmful symptoms. In a single Zinc treatment(50-850mg/L),the plant height, root length, biomass decreased and suffered serious symtoms.When the Zinc concentration was 250mg/L, the biomassr decreased to the minimum value of 2.86 g/pot, and showed signs of death,reached the lethal concentration.In the combined Pb-Zn treatment, When the Zinc concentration≤125mg/L and Lead concentrations≤600mg/L, had a certain role in promoting the growth of C. putuoshanensis,sp..The Lead concentration was 200mg/L and Zinc was 50mg/L,the biomass reached the maximum value of 17.44g/pot.(2) In a single Lead treatment(200-600mg/L), the root activity, total chlorophyll and soluble carbohydrate content showed an upward trend. When the Lead concentration was 600 mg/L, reached the maximum, respectively 261.70μgTTF/(g·h),1.96 mg/g·FW, 228.10 mmol/kg·FW, to improve C. putuoshanensis sp. tolerance toLead. While in a single Zinc treatment(50-850mg/L), the root activity and total chlorophyll showed a significant down trend. When the Zinc concentration was 250mg/L, decreased respectively to minimum 159.76μgTTF/(g·h),0.70 mg/g·FW, and leaf relative conductivity and MDA content were increased by 100.36%,87% compared with the control. In the combined Pb-Zn treatment, When the Zinc concentration ≤ 125mg/L and Lead concentrations≤600mg/L, Pb-Zn combined alleviated the harmful effects of zinc on root activity, chlorophyll and leaf membrane permeability to some extent.(3)Under the sand culture experiment, the single lead concentration was 2000 mg/L, the lead contents of the shoots and roots reached respectively 1046.43,2268.68 mg/ kg.While in the combined Pb-Zn treatment,a certain Zinc concentration can promote the absorption and enrichment Lead,even can reach the Pb hyperaccumulator state.When the Zinc concentration was 125mg/L and the Lead was 600mg/L,the content of Lead in shoots reached 2369.26mg/kg more than 2187.72mg/kg in roots,the Lead transport coefficient reached 1.08,the Lead bioconcentration coefficients of shoots and roots reached respectively 3.95,3.65,achieved and exceed the Pb hyperaccumulator standard. Thus, C. putuoshanensis sp. can be seen a new Pb hyperaccumulator.(4)In the single and combined Pb-Zn treatment, antioxidant effect of SOD, CAT, GSH were different. In a single Lead treatment(200-600mg/L), SOD activity showed an up trend, while the CAT activity and GSH content showed a down trend. In a single Zinc treatment(50-250mg/L), SOD activity decreased, while CAT activity and GSH content showed a rising trend. In the combined Pb-Zn treatment, When the Zinc concentration< 250mg/L and Lead concentrations< 600mg/L, SOD activity decreased, while CAT activity and GSH content showed a rising trend. When the Zinc concentration was 250mg/L and the Lead was 600mg/L, SOD decreased to the lowest 155 u/g·FW, leaf content of GSH reached a maximum of 432.30 nmol/g.(5)Chelating effect played an important role in Pb-Zn stress. In a single Lead treatment(200-600mg/L),the phytochelatin(PCs) contents in root and leaf showed an increasing trend.of C.putuoshanensis sp. When the Lead concentration was 600 mg/L, reached a maximum 384.83 nmol/g and 353.76 nmol/g.While in a single Zinc treatment(50-250mg/L), PCs contents of root and leaf decreased. In the combined Pb-Zn treatment, When the Zinc concentration≤125mg/L and Lead concentrations≤600mg/L, PCs contents of root and leaf showed an increasing trend. When the Zinc concentration was 50mg/L and the Lead was 600mg/L, PCs contents of root and leaf, reached respectively the maximum 410.28 nmol/g,461.67 nmol/g.The results showed that the C. putuoshanensis sp. had a high tolerance for Lead, and under certain concentration of Zinc showed hyperaccumulation’s ability to lead. This not only enriches the lead hyperaccumulator species and genetic diversity, but also find a new way to regulate Zinc to enrichment Lead capacity in plant, has certain theoretical and practical value to construct phytoremediation technology... |
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