| Screening accumulate plant is a key step for phytoextraction of the soil contaminated by heavy metals, and it is also difficult point and front field of phytoremediation of the contaminated environment. The field survey was conducted in Baofeng copper mine of Ya'an, and S. oldhamianus was selected as research material, then the soil culture was taken to study the physiological responses of growth, accumulation and the dynamics accumulation of S. oldhamianus at the treatments of Cd, Cu, Pb, respectively. Through the correlation analysis, regression analysis and variance analysis, the physiological characteristics and accumulation characteristics of S. oldhamianus were further researched.The main results were as follows:(1)The growth of S. oldhamianus was promoted at low Cd treatments and inhibited at high Cd treatments, and S. oldhamianus had great ability of accumulation to Cd.When the stress level of Cd was≤30 mg kg-1, the plant height, root length and biomass were more than the control,but the growth of S. oldhamianus started to be inhibited at Cd 60 mg kg-1 treatment, that the plant height, root length and biomass decreased gradually.The chlorophyll were inhabited obviously, which had negative correlation with the Cd treatments, r=-0.871**. The SOD activity in leaves and roots of S. oldhamianus enhanced at the Cd treatments; The CAT activity in leaves enhanced continuously, and that in roots enhanced firstly and then weakened with the turning points of Cd 1200 mg kg-1.The POD activity in leaves and roots of S. oldhamianus enhanced continuously and then weakened with the turning points of Cd 1500 mg kg-1,1200 mg kg-1. The Cd content of S. oldhamianus increased steadily at Cd treatments, but the accumulation of Cd had decreasing trend at high Cd treatments.The highest accumulation was 41.10μg/plant at the treatment of 90 mg kg-1.The highest content of Cd was 326.21 mg kg-1 in shoots,and all the enrichment coefficients were more than 1. The dynamics Cd accumulation of S. oldhamianus had positive correlation with the Cd treatments obviously:Considering the concentration and accumulation, it selected that the best sampling time was about 60 to 70 days for remediation of the Cd contaminated soil.(2) The growth of S. oldhamianus was inhabited by Cu obviously, and the accumulation of Cu increased at Cu treatments. The root length, biomass and chlorophyll of S. oldhamianus decreased gradually at Cu treatments, but the plant height increased at low Cu treatments and then became to decrease at Cu 1200 mg kg-1 treatment which was less than the control. The SOD activity in leaves and roots of S. oldhamianus enhanced at the Cu treatments; The CAT activity in leaves and roots of S. oldhamianus enhanced firstly and then weakened with the turning points of Cu 1500 mg kg-1,900 mg kg-1; So did the POD activity in leaves and roots with the turning points of Cu 900 mg kg-1,1200 mg kg-1.S. oldhamianus had the ability of accumulation to Cu. At the treatment of 1800 mg kg-1, The content of Cu was the highest,1097.35 mg kg-1 average in shoots, Cu accumulation was 1.21 mg/plant and the enrichment coefficient was more than 1. The dynamics Cu accumulation of S. oldhamianus had positive correlation with the Cu treatments obviously:Considering the concentration and accumulation, it selected that the best sampling time was more than or equal to 70 days for remediation of the Cu contaminated soil.(3) The growth of S. oldhamianus was inhabited by Pb obviously, and the accumulation of Pb increased at Pb treatments.The root length, biomass and chlorophyll of S. oldhamianus decreased at Pb treatments, but the plant height increased at low Pb treatments and then decreased at Cu 1200 mg kg-1 treatment, but all the plant height were higher than the control. The SOD activity in leaves and roots of S. oldhamianus enhanced firstly and then weakened at the Pb treatments, but the SOD activity in leaves were all higher than control, the SOD activity in roots were all lower than control except under Pb 1200 mg kg-1; The CAT activity in leaves and roots of S. oldhamianus enhanced firstly and then weakened with the turning points of Pb 900 mg kg-1,1200 mg kg-1；So did the POD activity in leaves and roots with the turning points of Pb 1200 mg kg-1,1500 mg kg-1, and the POD activity in leaves were all higher than the control. S. oldhamianus had great ability of accumulation to Pb. The highest content of Pb in shoot was 1463.86 mg kg-1.At the treatment of Pb 1200 mg kg-1, the Pb content was 1179.77 mg kg-1 in the shoots, Pb accumulation was the highest 7.09 mg/plant, and the translocation factor and enrichment coefficient were more than 1 at that treatment, that indicated S. oldhamianus was accumulate plant of Pb.The dynamics Pb accumulation of S. oldhamianus had positive correlation with the Pb treatments obviously:Considering the concentration and accumulation, it selected that the best sampling time was more than or equal to 70 days for remediation of the Pb contaminated soil. |
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