| This research selected Eupatorium adenophorum as the object, which is extensively grown in the Fuquan Lead-Zinc mining area, Hanyuan Count, Ya’an City, Sichuan Province. The composite and single heavy metals such as Cd, Zn, Pb and Cu stress tests are implemented for Eupatorium adenophorum for exploring the tolerance mechanism and enrichment characteristic thereof caused by the concentration gradient of the four heavy metals so as to discuss the potential of Eupatorium adenophorum applied to repair the polluted soil in the Sichuan Lead-Zinc mining are in which the plants are extensively grown. The main results of this research are as follow:Under the composite stress conditions, the average biomass of Eupatorium adenophorum is11.21g plant-1, so that is has a stronger enrichment capacity for Cd and Zn. At the wild mining area, the average concentrations of Cd and Zn for the aboveground part of Eupatorium adenophorum respectively reach1.68and457.14mg kg-1, and the average accumulation are repectively19.33and5305.09μg plant-1, thus a strong migration ability (TF>1) is applied to Cd, Zn and Cu, and a strong enrichment ability (BCF>1) is applied to Zn. Under the indoor cell composite stress conditions, the average concentrations of Cd and Zn for the aboveground part of Eupatorium adenophorum respectively reach6.93±2.42and136.60±46.76mg kg-1, and the average accumulations are repectively86.62±38.43and1630.56±547.24μg plant-1, thus a strong migration ability (TF>1) is applied to Cd and Zn.Eupatorium adenophorum shows strong tolerance and enrichment characteristics for Cd stress. As the increasing of the Cd concentration, plant height, biomass, roots, and CAT and POD enzymatic activities and soluble protein contents in leaves are going to go up and come down, and the net photosynthetic rate is gradually declined; the Cd concentration in each organ is gradually increased, and the highest concentrations of stems and leaves are respectively113.11±9.58and196.56±17.02mg kg-1; the accumulation of Cd in each organ is going to go up and come down, and the maximums of accumulation of stems and leaves are respectively1.26±0.29and0.91±0.45mg pot-1.Its root BCT, aboveground BCF and TF are maximally up to1.37,3.71and3.44, which are all more than the hyperaccumulator threshold1.Eupatorium adenophorum shows strong tolerance and enrichment characteristics for Zn stress. As the increasing of the Zn concentration, plant height, length of root, biomass, CAT, POD, soluble protein contents, stomatal conductance, intercellular CO2concentration and transpiration rate are going to go up and come down; the Zn content in each organ is gradually increased, and the highest concentration of stems and leaves are respectively2066.28±377.55and2243.46±356.09mg kg-1;he cumulant of Zn in each organ is going to go up and come down, and the maximums of accumulations of stems and leaves are respectively18.10±5.44and12.18±4.36mg pot-1. Its root BCT, aboveground BCF and TF are maximally up to0.42,0.54and1.58.Eupatorium adenophorum shows strong tolerance and enrichment characteristics for Pb stress. As the increasing of the Pb concentration, plant height, length of root, biomass, CAT, POD, soluble protein contents, stomatal conductance, intercellular CO2concentration and transpiration rate are going to go up and come down; the Pb content in each organ is gradually increased, and the highest concentration of stems is1006.33±76.51mg kg-1; the accumulations of Pb in each organ is going to go up and come down, and the maximums of stems is2.54±0.88mg pot-1. Its root BCT is1.32-2.63, which is more than the hyperaccumulator threshold1(BCF>1). Eupatorium adenophorum shows certain tolerance and enrichment characteristics for Cu stress. As the increasing of the Cu concentration, plant height is gradually declined, and length of root, biomass, CAT, and POD are going to go up and come down; the Cu concentration in each organ is gradually increased, and the highest concentration of stems is38.99±4.55mg kg-1; the accumulations of Cu in each organ is going to go up and come down, and the maximum of accumulation of stems is373.15±192.00μ.g pot-1. Its root BCT, aboveground BCF and TF are maximally up to0.74,0.38and0.71.To sum up, Eupatorium adenophorum shows strong tolerance and enrichment characteristics for Cd and Zn, and shows certain tolerance and enrichment characteristics for Pb and Cu. The biomass of Eupatorium adenophorum is large, the Eupatorium adenophorum can normally grow under the composite and single stress conditions of heavy metals Cd, Zn, Pb and Cu, and can absorb heavy metals and enrich them to the aboveground, thus there is a great potential for applying Eupatorium adenophorum for repairing heavy metal Cd, Zn, Pb and Cu polluted soil in Lead-Zinc mining area. |
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