Zn accumulation and subcellular distribution in leaves of the hyperaccumulating ecotype （HE） and non-hyperaccumulating ecotype （NHE） of Sedum alfredii Hance were studied using radiotracer and gradient centrifugati...Zn accumulation and subcellular distribution in leaves of the hyperaccumulating ecotype （HE） and non-hyperaccumulating ecotype （NHE） of Sedum alfredii Hance were studied using radiotracer and gradient centrifugation techniques. Leaf Zn accumulation in the HE of S. alfredii was 18.5-26.7 times greater than that in the NHE when the plants were grown at 1-500μmol Zn L-1. Leaf section uptake of 65Zn was highly dependent on external Zn levels. Greater 65Zn uptake in HE was noted only at external Zn levels 〉 100μmol L-1. Zinc subcellular distribution in the leaves of the two ecotypes of S. alfredii was： cell wall 〉 soluble fraction 〉 cell organelle. However, more Zn was distributed to the leaf cell wall and soluble fractions for HE than for NHE. In the leaf of HE, 91%-94% of the Zn was found in the cell walls and the soluble fraction and only 6%-9% Zn was distributed in the cell organelle fraction. For NHE, about 20%-26% Zn was recovered in the cell organelle fraction. In stems, Zn distribution to the ceil wail fraction was approximately two fold greater in the HE than that in the NHE. For the hyperaccumulating ecotype of S. alfredii, the cell wall and the vacuole played a very important role in Zn tolerance and hyperaccumulation.展开更多
Commelina communis L. growing over some new copper mining wastelands at Bijiashan, Tongling City of Anhui Province, China, was found to be a copper hyperaccumulator. Its copper concentrations were 2707-6159 (4439±...Commelina communis L. growing over some new copper mining wastelands at Bijiashan, Tongling City of Anhui Province, China, was found to be a copper hyperaccumulator. Its copper concentrations were 2707-6159 (4439±2434) mg kg-1, 369-831 (731±142) mg kg-1, and 429-587 (547±57) mg kg-1, respectively, in the roots, stems, and leaves. The soils supporting the growth of the species had a copper concentration ranging from 4620 to 5020 mg kg-1 and averaging 4835±262 mg kg-1, suggesting that the species could not only grow on heavily copper-contaminated soils but also accumulate extraordinarily high concentration of copper. Thus, it shows great potential in the phytoremediation of copper-contaminated soils,the restoration of mined land, geochemical prospecting, and the study of environmental pollution changes.展开更多
The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metall...The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd) uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h) root uptake of 109 Cd increased significantly,and higher 109 Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109 Cd taken up was distributed to the shoots in plants with citric acid(CA) treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.展开更多
Synchrotron radiation extended X-ray absorption fine structure(SR EXAFS)was used to study the transformation of coordination and redox state of arsenic(As)in a newly discovered As hyperaccumulator,Pteris vittata L.,wh...Synchrotron radiation extended X-ray absorption fine structure(SR EXAFS)was used to study the transformation of coordination and redox state of arsenic(As)in a newly discovered As hyperaccumulator,Pteris vittata L.,which is considered to have great potential for phytoremediating the As contaminated soil.It is shown that the As in this plant was mainly coordinated with oxygen in thereduced state,As(IIl),and the reduction of As(V)occurred in the root after it was taken up.No oxidationof As(II)was found during the translocation of As,from root to shoot.Only a small amount of As was coordinated with sulfur in root and petiole,but not distinct in pinna.展开更多
We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfred...We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance.展开更多
The active metabolite in the post-harvested biomass of zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in China.The current study demonstrates that a salidrosid...The active metabolite in the post-harvested biomass of zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in China.The current study demonstrates that a salidroside-type metabolite can be yielded from the Zn/Cd hyperaccumulator S.alfredii biomass by means of sonication/ethanol extraction and macroporous resin column(AB-8 type) isolation.The concentrations of Zn and Cd in the salidroside-type metabolite were below the limitation of the national standards.展开更多
A brief introduce to environmental and ecological characteristics, hyperaccumulators of rare earth elements （REEs）, as well as the scientific significance of REE hyperaccumulators were presented. Based on this intro...A brief introduce to environmental and ecological characteristics, hyperaccumulators of rare earth elements （REEs）, as well as the scientific significance of REE hyperaccumulators were presented. Based on this introduce, the achievements in REE hyperaccumulator research, which were ： （ 1 ） The species and regional distribution of REE hyperaccumulators,展开更多
Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent.The research was carried out in two phases:1)a leaching study to determine the zinc extr...Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent.The research was carried out in two phases:1)a leaching study to determine the zinc extraction efficiency of this leaching agent,and 2)a thermodynamic analysis to identify the likely reactions and stable Zn(Ⅱ)species formed in the leaching systems.Taguchi orthogonal experiment,with four variable parameters,leaching temperature,molar ratio of NH4Cl to NH3,leaching time and solid-to-liquid(L/S)ratio,and each at three levels,was used to optimize the experiment parameters by the analysis of variances.The results indicate that leaching temperature has the most dominant effect on metal extraction performance,followed by molar ratio of NH4Cl to NH3,solid-to-liquid ratio and leaching time.The optimum condition was obtained as follows:temperature of 60℃,molecular ratio of NH4Cl to NH3 of 0.6,leaching time of 2 h and solid-to-liquid ratio of 5-1.The total zinc leaching efficiency under optimum conditions reaches 97.95%.The thermodynamic study indicates that the dominant species produced by the leaching process should be the soluble Zn(NH3)4 2+.展开更多
Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MDA）, reactive oxygen species （ROS） and antioxidases （catalase...Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MDA）, reactive oxygen species （ROS） and antioxidases （catalase （CAT）; superoxide dismutase （SOD）; peroxidase （POD）） in the leaf were determined when S. alfredii was treated for 15 d with various CdC12 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2＇,7＇-dichlorofluorescein （DCF）, which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20277035)the National Key Basic Research Program (973 Program) of China (No. 2002CB410804).
文摘Zn accumulation and subcellular distribution in leaves of the hyperaccumulating ecotype （HE） and non-hyperaccumulating ecotype （NHE） of Sedum alfredii Hance were studied using radiotracer and gradient centrifugation techniques. Leaf Zn accumulation in the HE of S. alfredii was 18.5-26.7 times greater than that in the NHE when the plants were grown at 1-500μmol Zn L-1. Leaf section uptake of 65Zn was highly dependent on external Zn levels. Greater 65Zn uptake in HE was noted only at external Zn levels 〉 100μmol L-1. Zinc subcellular distribution in the leaves of the two ecotypes of S. alfredii was： cell wall 〉 soluble fraction 〉 cell organelle. However, more Zn was distributed to the leaf cell wall and soluble fractions for HE than for NHE. In the leaf of HE, 91%-94% of the Zn was found in the cell walls and the soluble fraction and only 6%-9% Zn was distributed in the cell organelle fraction. For NHE, about 20%-26% Zn was recovered in the cell organelle fraction. In stems, Zn distribution to the ceil wail fraction was approximately two fold greater in the HE than that in the NHE. For the hyperaccumulating ecotype of S. alfredii, the cell wall and the vacuole played a very important role in Zn tolerance and hyperaccumulation.
文摘Commelina communis L. growing over some new copper mining wastelands at Bijiashan, Tongling City of Anhui Province, China, was found to be a copper hyperaccumulator. Its copper concentrations were 2707-6159 (4439±2434) mg kg-1, 369-831 (731±142) mg kg-1, and 429-587 (547±57) mg kg-1, respectively, in the roots, stems, and leaves. The soils supporting the growth of the species had a copper concentration ranging from 4620 to 5020 mg kg-1 and averaging 4835±262 mg kg-1, suggesting that the species could not only grow on heavily copper-contaminated soils but also accumulate extraordinarily high concentration of copper. Thus, it shows great potential in the phytoremediation of copper-contaminated soils,the restoration of mined land, geochemical prospecting, and the study of environmental pollution changes.
基金Project supported by the National Natural Science Foundation of China(No.31000935)he Fundamental Research Funds for the Central Universities(No.2012FZA6008)the Department of Science & Technology of Zhejiang Province(No.2011C22077),China
文摘The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd) uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h) root uptake of 109 Cd increased significantly,and higher 109 Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109 Cd taken up was distributed to the shoots in plants with citric acid(CA) treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.
文摘Synchrotron radiation extended X-ray absorption fine structure(SR EXAFS)was used to study the transformation of coordination and redox state of arsenic(As)in a newly discovered As hyperaccumulator,Pteris vittata L.,which is considered to have great potential for phytoremediating the As contaminated soil.It is shown that the As in this plant was mainly coordinated with oxygen in thereduced state,As(IIl),and the reduction of As(V)occurred in the root after it was taken up.No oxidationof As(II)was found during the translocation of As,from root to shoot.Only a small amount of As was coordinated with sulfur in root and petiole,but not distinct in pinna.
基金supported by the National Natural Science Foundation of China (No. 30630046)the Hi-Tech Research and Development Program (863) of China (No. 2006AA06Z386)the Program for Changjiang Scholars and Innovative Research Team in University, China (No. IRT0536)
文摘We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance.
基金Project supported by the Education Department of Zhejiang Province(No. Y201016563)the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (No. 2009490711)the Zhejiang Provincial Qianjiang Talents for Science and Technology(No. 2011R10026),China
文摘The active metabolite in the post-harvested biomass of zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in China.The current study demonstrates that a salidroside-type metabolite can be yielded from the Zn/Cd hyperaccumulator S.alfredii biomass by means of sonication/ethanol extraction and macroporous resin column(AB-8 type) isolation.The concentrations of Zn and Cd in the salidroside-type metabolite were below the limitation of the national standards.
文摘A brief introduce to environmental and ecological characteristics, hyperaccumulators of rare earth elements （REEs）, as well as the scientific significance of REE hyperaccumulators were presented. Based on this introduce, the achievements in REE hyperaccumulator research, which were ： （ 1 ） The species and regional distribution of REE hyperaccumulators,
基金Project(KY20080577000002)supported by the Hi-tech Research and Development Program of ChinaProject(20080431028)supported by China Postdoctoral Science FoundationProject(50804056)supported by the National Natural Science Foundation of China
文摘Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent.The research was carried out in two phases:1)a leaching study to determine the zinc extraction efficiency of this leaching agent,and 2)a thermodynamic analysis to identify the likely reactions and stable Zn(Ⅱ)species formed in the leaching systems.Taguchi orthogonal experiment,with four variable parameters,leaching temperature,molar ratio of NH4Cl to NH3,leaching time and solid-to-liquid(L/S)ratio,and each at three levels,was used to optimize the experiment parameters by the analysis of variances.The results indicate that leaching temperature has the most dominant effect on metal extraction performance,followed by molar ratio of NH4Cl to NH3,solid-to-liquid ratio and leaching time.The optimum condition was obtained as follows:temperature of 60℃,molecular ratio of NH4Cl to NH3 of 0.6,leaching time of 2 h and solid-to-liquid ratio of 5-1.The total zinc leaching efficiency under optimum conditions reaches 97.95%.The thermodynamic study indicates that the dominant species produced by the leaching process should be the soluble Zn(NH3)4 2+.
基金Project supported by the Wuhan Chenguang Project for Youth Scholar(No.20045006071-24)"211 Project"of Educational Ministry of China
文摘Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MDA）, reactive oxygen species （ROS） and antioxidases （catalase （CAT）; superoxide dismutase （SOD）; peroxidase （POD）） in the leaf were determined when S. alfredii was treated for 15 d with various CdC12 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2＇,7＇-dichlorofluorescein （DCF）, which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.
