Copper accumulation and intracellular distribution in Elsholtzia splendens, a native Chinese Cu-tolerant and accu- mulating plant species, was investigated by transmission electron microscope (TEM) and gradient centri...Copper accumulation and intracellular distribution in Elsholtzia splendens, a native Chinese Cu-tolerant and accu- mulating plant species, was investigated by transmission electron microscope (TEM) and gradient centrifugation techniques. Copper concentrations in roots, stems and leaves of E. splendens increased with increasing Cu levels in solution. After exposure to 500 μmol/L Cu for 8 d, about 1000 mg/kg Cu were accumulated in the stem and 250 mg/kg Cu in the leaf of E. splendens. At 50 μmol/L Cu, no significant toxicity was observed in the chloroplast and mitochondrion within its leaf cells, but separation appeared at the cytoplasm and the cell wall within the root cells. At >250 μmol/L Cu, both root and leaf organelles in E. splendens were damaged heavily by excessive Cu in vivo. Copper subcellular localization in the plant leaf after 8 days’ exposure to 500 μmol/L Cu using gradient centrifugation techniques was found to be decreased in the order: chloroplast>cell wall>soluble fraction>other organelles. The plant root cell wall was found to be the site of highest Cu localization. Increase of Cu exposure time from 8 d to 16 d, increased slightly Cu concentration in cell wall fraction in roots and leaves, while that in the chloroplast fraction decreased in leaves of the plants grown in both 0.25 μmol/L and 500 μmol/L Cu. TEM confirmed that much more Cu localized in cell walls of E. splendens roots and leaves, but also more Cu localized in E. splendens’ chloroplast when the plant is exposed to Cu levels>250 μmol/L, as compared to those in the plant grown in 0.25 μmol/L Cu. Copper treatment at levels>250 μmol/L caused pronounced damage in the leaf chloroplast and root organelles. Copper localization in cell walls and chloroplasts could mainly account for the high detoxification of Cu in E. splendens.展开更多
Based on the Industrial Source Complex Short-Term Version 3 （ISCST3） model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans （PCDD/F...Based on the Industrial Source Complex Short-Term Version 3 （ISCST3） model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans （PCDD/Fs） of agricultural soil, within a radius of 3 kin from a municipal solid waste incinerator （MSWI） plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent （I-TEQ） values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and K-TEQ values were generally lower than their observations, and that the higher the degree of underestimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 kin of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra- and penta-chlorinated dioxins.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20307008) and the National Basic Research Program(973) (No. 2002CB410804) of China
文摘Copper accumulation and intracellular distribution in Elsholtzia splendens, a native Chinese Cu-tolerant and accu- mulating plant species, was investigated by transmission electron microscope (TEM) and gradient centrifugation techniques. Copper concentrations in roots, stems and leaves of E. splendens increased with increasing Cu levels in solution. After exposure to 500 μmol/L Cu for 8 d, about 1000 mg/kg Cu were accumulated in the stem and 250 mg/kg Cu in the leaf of E. splendens. At 50 μmol/L Cu, no significant toxicity was observed in the chloroplast and mitochondrion within its leaf cells, but separation appeared at the cytoplasm and the cell wall within the root cells. At >250 μmol/L Cu, both root and leaf organelles in E. splendens were damaged heavily by excessive Cu in vivo. Copper subcellular localization in the plant leaf after 8 days’ exposure to 500 μmol/L Cu using gradient centrifugation techniques was found to be decreased in the order: chloroplast>cell wall>soluble fraction>other organelles. The plant root cell wall was found to be the site of highest Cu localization. Increase of Cu exposure time from 8 d to 16 d, increased slightly Cu concentration in cell wall fraction in roots and leaves, while that in the chloroplast fraction decreased in leaves of the plants grown in both 0.25 μmol/L and 500 μmol/L Cu. TEM confirmed that much more Cu localized in cell walls of E. splendens roots and leaves, but also more Cu localized in E. splendens’ chloroplast when the plant is exposed to Cu levels>250 μmol/L, as compared to those in the plant grown in 0.25 μmol/L Cu. Copper treatment at levels>250 μmol/L caused pronounced damage in the leaf chloroplast and root organelles. Copper localization in cell walls and chloroplasts could mainly account for the high detoxification of Cu in E. splendens.
基金Project (Nos. X506312 and X206955) supported by the NaturalScience Foundation of Zhejiang Province, China
文摘Based on the Industrial Source Complex Short-Term Version 3 （ISCST3） model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans （PCDD/Fs） of agricultural soil, within a radius of 3 kin from a municipal solid waste incinerator （MSWI） plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent （I-TEQ） values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and K-TEQ values were generally lower than their observations, and that the higher the degree of underestimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 kin of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra- and penta-chlorinated dioxins.
