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
Elsholtzia argyi and Elsholtzia splendens, which are Chinese endemic Pb/Zn mined and Cu mined ecotype respec- tively, were investigated on the aspect of their response to Pb toxicity in the presence or absence of EDTA...Elsholtzia argyi and Elsholtzia splendens, which are Chinese endemic Pb/Zn mined and Cu mined ecotype respec- tively, were investigated on the aspect of their response to Pb toxicity in the presence or absence of EDTA addition. After 8 d’s Pb treatment, root length, root surface area and root volume of E. splendens decreased much more than those of E. argyi, and reduced considerably with increase of Pb, while no marked change was noted for root average diameter. Compared to E. argyi, length of root with diameter (D)<0.2 mm was significantly reduced for E. splendens as Pb increased. D<0.1 mm E. splendens root had cross-sectional surface area at Pb≥10 mg/L, while for E. argyi, it was at Pb≥25 mg/L. With increase of Pb, DW of E. splendens decreased much more than that of E. argyi. E. argyi exhibited much more tolerance to Pb toxicity than E. splendens. Treatment with 100 mg/L Pb plus 50 mmol/L EDTA significantly decreased the length and surface area of D≤0.2 mm root, increased the length and surface area of 0.2≤D≤0.8 mm root for the case of E. argyi, while for E. splendens, length and surface area of D<0.6 mm root reduced, as compared to 100 mg/L Pb treatment, alone. At 100 mg/L Pb, shoot Pb accumulation in E. splendens and E. argyi were 27.9 and 89.0 μg/plant DW respectively, and much more Pb was uptaken by the root and translocated to the stem of E. argyi as compared to E. splendens. Treatment of the plant with 100 mg/L Pb plus 50 mmol/L EDTA increased leaf Pb accumulation from 16.8 to 84.9 g/plant for E.splendens and from 18.8 to 52.5 g/plant for E. argyi, while both root and stem Pb pronouncedly reduced for both Elsholtzia species. The increased translocation of Pb to the leaf of E. splendens being than that of E. argyi after treatment with 100 mg/L Pb plus 50 mmol/L EDTA should be further investigated.展开更多
A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu fro...A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu from 0.25 to 500 ?mol/L significantly enhanced levels of GABA and histidine (His), but considerably decreased levels of aspartate (Asp) and glutamate (Glu) in the leaves. The leaf Asp level negatively correlated with leaf Cu level, while leaf GABA level positively correlated with leaf Cu level. The leaf Glu level negatively correlated with leaf GABA level in Elsholtzia splendens. The depletion of leaf Glu may be related to the enhanced synthesis ofleafGABA under Cu stress.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 supported by the National Basic Research Program (973)(No. 2002CB410804) of China and the National Natural ScienceFoundation of China (No. 20307008)
文摘Elsholtzia argyi and Elsholtzia splendens, which are Chinese endemic Pb/Zn mined and Cu mined ecotype respec- tively, were investigated on the aspect of their response to Pb toxicity in the presence or absence of EDTA addition. After 8 d’s Pb treatment, root length, root surface area and root volume of E. splendens decreased much more than those of E. argyi, and reduced considerably with increase of Pb, while no marked change was noted for root average diameter. Compared to E. argyi, length of root with diameter (D)<0.2 mm was significantly reduced for E. splendens as Pb increased. D<0.1 mm E. splendens root had cross-sectional surface area at Pb≥10 mg/L, while for E. argyi, it was at Pb≥25 mg/L. With increase of Pb, DW of E. splendens decreased much more than that of E. argyi. E. argyi exhibited much more tolerance to Pb toxicity than E. splendens. Treatment with 100 mg/L Pb plus 50 mmol/L EDTA significantly decreased the length and surface area of D≤0.2 mm root, increased the length and surface area of 0.2≤D≤0.8 mm root for the case of E. argyi, while for E. splendens, length and surface area of D<0.6 mm root reduced, as compared to 100 mg/L Pb treatment, alone. At 100 mg/L Pb, shoot Pb accumulation in E. splendens and E. argyi were 27.9 and 89.0 μg/plant DW respectively, and much more Pb was uptaken by the root and translocated to the stem of E. argyi as compared to E. splendens. Treatment of the plant with 100 mg/L Pb plus 50 mmol/L EDTA increased leaf Pb accumulation from 16.8 to 84.9 g/plant for E.splendens and from 18.8 to 52.5 g/plant for E. argyi, while both root and stem Pb pronouncedly reduced for both Elsholtzia species. The increased translocation of Pb to the leaf of E. splendens being than that of E. argyi after treatment with 100 mg/L Pb plus 50 mmol/L EDTA should be further investigated.
文摘A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu from 0.25 to 500 ?mol/L significantly enhanced levels of GABA and histidine (His), but considerably decreased levels of aspartate (Asp) and glutamate (Glu) in the leaves. The leaf Asp level negatively correlated with leaf Cu level, while leaf GABA level positively correlated with leaf Cu level. The leaf Glu level negatively correlated with leaf GABA level in Elsholtzia splendens. The depletion of leaf Glu may be related to the enhanced synthesis ofleafGABA under Cu stress.
