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
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
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
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
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
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
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
Neptunia amplexicaulis is an herbaceous legume endemic to the Richmond area in central Queensland,Australia and is one of the strongest known Selenium hyperaccumulators on earth,showing significant potential to be uti...Neptunia amplexicaulis is an herbaceous legume endemic to the Richmond area in central Queensland,Australia and is one of the strongest known Selenium hyperaccumulators on earth,showing significant potential to be utilised in Se phytoextraction applications.Here a protocol was established for in vitro micropropagation of Se hyperaccumula-tor N.amplexicaulis using nodal segments from in vitro-germinated seedlings.Shoot multiplication was achieved on Murashige and Skoog(MS)basal media supplemented with various concentrations of 6-Benzylaminopurine(BA)(1.0,2.0,3.0 mg L^(−1))alone or in combination with low levels of Naphthaleneacetic acid(NAA)(0.1,0.2,0.3 mg L^(−1)),with 2.0 mg L^(−1) BA+0.2 mg L^(−1) NAA found to be most effective.Elongated shoots were rooted in vitro using NAA,with highest root induction rate of 30%observed at 0.2 mg L^(−1) NAA.About 95%of the in vitro rooted shoots survived acclimatization.Clonally propagated plantlets were dosed with selenate/selenite solution and assessed for Se tissue concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy(ICP-AES)and found to retain their ability to hyperaccumulate.The protocol developed for this study has potential to be optimised for generating clonal plants of N.amplexicaulis for use in research and phytoextraction industry applications.展开更多
The trace element selenium is essential for human nutrition but is distributed unevenly in soils worldwide with exten-sive selenium-deficient regions and selenium-enriched(seleniferous)areas.Neptunia amplexicaulis is ...The trace element selenium is essential for human nutrition but is distributed unevenly in soils worldwide with exten-sive selenium-deficient regions and selenium-enriched(seleniferous)areas.Neptunia amplexicaulis is one of the strongest selenium hyperaccumulator plants known and native to Australian seleniferous soils.Research in the genetic background of the selenium accumulation and tolerance mechanisms of this species lacks biotech-nological and molecular tools for functional genetics.Therefore,this study aimed to develop a de novo shoot regen-eration protocol for N.amplexicaulis and validate an selenium accumulation test system.Callus was induced on root and hypocotyl explants excised from 5-day old seedlings and cultured on an adjusted MS medium(SIM9)containing 4.5 μM Thidiazuron(TDZ)for two weeks in darkness.After this period,the TDZ concentration was reduced to 0.45 μM,and the explants were transferred to light conditions.In addition,seedlings of N.amplexicaulis,N.heliophila and Med-icago truncatula were placed on vertical MS agar plates containing 1.5 mM(standard)or 0.1 mM(low)magnesium sulphate with 0,30,90 μM sodium selenate.Initial shoot differentiation was observed 6 weeks after culture initia-tion.This regeneration response was successfully repeated in a second experiment.The outgrow of the shoot buds into complete shoots was not yet achieved but requires additional media optimization.Additionally,spontaneous shoot regeneration from a root was observed,highlighting potential for further studies.In vitro grown seedlings dem-onstrated efficient,selective selenium uptake in N.amplexicaulis and identified M.truncatula as a secondary selenium accumulator with selenium concentrations of>300 μg Se g^(-1) DM.This project presents the first protocol for inducing early stages of development of indirect shoot organogenesis in N.amplexicaulis from hypocotyl and root explants as prerequisite for genetic transformation,though completing the regeneration cycle remains challenging.Neptunia amplexicaulis hyperaccumulates selenium also under in vitro conditions.展开更多
Coal mining activities significantly impact the environment through water,soil,and air pollution of the surrounding areas.The dispersal of pollutants and the degradation of soil quality by toxic metals emitted from co...Coal mining activities significantly impact the environment through water,soil,and air pollution of the surrounding areas.The dispersal of pollutants and the degradation of soil quality by toxic metals emitted from coal mining activities cause significant concerns worldwide,posing serious risks to ecosystems,human health,and vegetation.Restoration of quality of soil contaminated by toxic metals from coal mining is challenging due to the continuous increase in the concentration of toxic metals such as lead,copper,chromium,cadmium,and arsenic within the soil matrix.Conventional approaches utilized for the remediation of soil are often time-consuming and labour-intensive.In addition,they may lead to secondary pollution,particularly when applied at a large scale.Phytoremediation,a technique that utilizes plants with high metal accumulation capacity,has surfaced as a promising,eco-friendly strategy for remediating soil contaminated with toxic metals.These plants can absorb and sequester metals into above-and belowground tissues or stabilize them into less bioavailable forms within the rhizosphere.Species from families such as Brassicaceae and Asteraceae have demonstrated notable effectiveness in phytoremediation applications.The efficiency of phytoremediation can be further enhanced by applying organic and inorganic soil amendments to increase metal bioavailability and plant uptake.Moreover,genetic engineering has enabled the development of plants with improved metal tolerance and accumulation capacities.Complementing these approaches,microbial phytoremediation employs plant-associated microbes to facilitate metal uptake and transformation,increasing the overall remediation efficiency.Following remediation,biomass is proposed for value-added applications,including biochar,biogas,and recovery of metals for industrial reuse.This review summarizes the current progress,emerging strategies,and future prospects of phytoremediation for mitigating toxic metal pollution in coal mining-affected soils.Altogether,these approaches illustrate the potential of integrating circular bioeconomy principles in transforming phytoremediation as a sustainable strategy for mitigating toxic metal pollution in coal mining regions.展开更多
Pot experiment was conducted to understand the effect of phosphorus on arsenic accumulation in As-hyperaccumulator Chinese brake (Pteris vittata L.). It is shown that arsenic concentrations in the fronds and rhizoids,...Pot experiment was conducted to understand the effect of phosphorus on arsenic accumulation in As-hyperaccumulator Chinese brake (Pteris vittata L.). It is shown that arsenic concentrations in the fronds and rhizoids, the arsenic bioaccumulation factor, and the total arsenic in the fronds were not influenced significantly under low levels of phosphorus (≤400 mg/kg) and increased sharply under high levels of phosphorus (】400 mg/ kg). The discovery implies that the efficiency of arsenic removal in phytoremedia-tion using the hyperaccumulating plant can be greatly elevated by the phosphorus addition at high rates. The interaction between the accumulation of phosphorus and that of arsenic in plant was stimulated mutually. The result represents that Chinese brake is a good material for plant physiologist to conduct comparative and mechanism studies on the uptake behaviors of phosphorus and arsenic, and phosphorus is also a potential accelerator for phytoremediation of arsenic-contaminated soils.展开更多
Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperacc...Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var ner-vosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2HAsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.展开更多
Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Mo...Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Moq.). K. folium and S. salsa had a NaCl content of 32.1% and 29.8%, respectively, on a dry weight basis. X-ray microanalysis of the Na+ in the vacuole, apoplasts and cytoplasm of the two plants indicated a ratio of 7.3:5.6:1.0 in K. folium and 7.3:6.6:1.0 in S. salsa. These data show that K. folium and S. salsa both have a high Na+ and Cl- accumulating capacity, which is related to high activity of tonoplast H+-ATPase and H+-PPase.展开更多
The distributions of arsenic and 6 essential elements in the pinna of As hyperaccumulator,Pteris vittata L.,were studied using synchrotron radiation X-ray fluorescence(SRXRF).Significant correlation between the distri...The distributions of arsenic and 6 essential elements in the pinna of As hyperaccumulator,Pteris vittata L.,were studied using synchrotron radiation X-ray fluorescence(SRXRF).Significant correlation between the distribution and mobility of the elements revealed that SRXRF study on the elemental distribution was feasible to inspect the transportations of elements in plants.The distribution of As in the pinna showed that As had great abilities to be transported in xylem vessels and from xylem to mesophyll.The distribution of K,one of the most mobile elements in plants,was similar to that of As,whereas the distributions of Fe and Ca with less mobility in plants were almost opposite to that of As in the pinna.展开更多
Phytoextraction is a promising option for purifying hexavalent chromium(Cr(Ⅵ))-laden wastewater,but the long remediation period incurred by poor growth rate of Cr hyperaccumulators remains a primary hindrance to its ...Phytoextraction is a promising option for purifying hexavalent chromium(Cr(Ⅵ))-laden wastewater,but the long remediation period incurred by poor growth rate of Cr hyperaccumulators remains a primary hindrance to its large-scale application.In this study,we performed a hydroponic experiment to evaluate the feasibility of promoting the growth and phytoextraction efficiency of Cr hyperaccumulator Leersia hexandra Swartz(L.hexandra)by inoculating plant growth-promoting rhizobacteria(PGPR)Bacillus cereus(B.cereus).In batch tests,the Cr(Ⅵ)removal rates of L.hexandra and B.cereus co-culture were greater than the sum of their respective monocultures.This was likely due to the microbial reduction of Cr(Ⅵ)to Cr(Ⅲ),which is amiable to plant uptake.Besides,the PGPR factors of B.cereus,including indoleacetic acid(IAA)production,1-aminocyclopropane-1-carboxylic acid deamination(ACCd)activity,phosphate solubilization capacity,and siderophore production,were quantified.These PGPR factors helped explain the biomass augmentation,root elongation and enhanced Cr enrichment of the inoculated L.hexandra in pot experiments.Despite the increased Cr uptake,no aggravated oxidative damage to the cell membrane was observed in the inoculated L.hexandra.This was attributed to its capacity to confront the increased intracellular Cr stress by upregulating both the activities of antioxidative enzymes and expression of metal-binding proteins/peptides.Moreover,L.hexandra could always conserve the majority of Cr in the residual and oxalic integrated forms with low mobility and phytotoxicity,irrespective of the B.cereus inoculation.These results highlight the constructed Cr hyperaccumulatorrhizobacteria consortia as an effective candidate for decontaminating Cr(Ⅵ)-laden wastewater.展开更多
The high levels of some metals in metal hyperaccumulator plants may be transferred to insect associates. We surveyed insects collected from the South African Ni hyperaccumulator Berkheya coddii to document whole-body ...The high levels of some metals in metal hyperaccumulator plants may be transferred to insect associates. We surveyed insects collected from the South African Ni hyperaccumulator Berkheya coddii to document whole-body metal concentrations （Co, Cr, Cu, Mg, Mn, Ni, Pb, Zn）. We also documented the concentrations of these metals in leaves, stems and inflorescences, finding extremely elevated levels of Ni （4 700-16 000μg/g） and high values （5-34μg/g） for Co, Cr, and Pb. Of 26 insect morphotypes collected from B. coddii, seven heteropterans, one coleopteran, and one orthopteran contained relatively high concentrations of Ni （〉 500μg/g）. The large number of high-Ni heteropterans adds to discoveries of others （from California USA and New Caledonia） and suggests that members of this insect order may be particularly Ni tolerant. Nymphs of the orthopteran （Stenoscepa） contained 3 500 μg Ni/g, the greatest Ni concentration yet reported for an insect. We also found two beetles with elevated levels of Mg （〉 2 800 μg/g）, one beetle with elevated Cu （〉 70 μg/g） and one heteropteran with an elevated level of Mn （〉 200 μg/g）. Our results show that insects feeding on a Ni hyperaccumulator can mobilize Ni into food webs, although we found no evidence of Ni biomagnification in either herbivore or carnivore insect taxa. We also conclude that some insects associated with hyperaccumulators can contain Ni levels that are high enough to be toxic to vertebrates.展开更多
Arthropods （mainly insects） were collected from a forest site that contained at least six species of Ni hyperaccumulators. Whole body Ni analysis was performed for 12 arthropod taxa, two of which were studied at dif...Arthropods （mainly insects） were collected from a forest site that contained at least six species of Ni hyperaccumulators. Whole body Ni analysis was performed for 12 arthropod taxa, two of which were studied at different life cycle stages. We found two Nitolerant insects. The pentatomid heteropteran Utana viridipuncta, feeding on fruits of the Ni hyperaccumulator Hybanthus austrocaledonicus, contained a mean of 2 600 μg Ni/g in nymphs and 750μg Ni/g in adults. The tephritid fly Bactrocera psidii, feeding on pulp of Sebertia acuminata fruits that contained 6 900μg Ni/g, contained 420μg Ni/g as larvae that had evacuated their guts and significantly less （65μg Ni/g） as adults. European honeybees （Apis mellifera） visiting flowers of the Ni hyperaccumulator H. austrocaledonicus contained significantly more Ni （8-fold more） than those collected from flowers of Myodocarpus fraxinifolius, a non-hyperaccumulator. Our results show that some insects feed on Ni hyperaccumulator plants and that their feeding mobilizes Ni into local food webs.展开更多
Nymphs of Stenoscepa sp. feed on leaves of the Ni hyperaccumulator Berkheya coddii at serpentine sites in Mpumalanga Province, South Africa. These sites contain Ni hyperaccumulators, Ni accumulators, and plants with N...Nymphs of Stenoscepa sp. feed on leaves of the Ni hyperaccumulator Berkheya coddii at serpentine sites in Mpumalanga Province, South Africa. These sites contain Ni hyperaccumulators, Ni accumulators, and plants with Ni concentrations in the normal range. We conducted studies to： （i） determine the whole-body metal concentration of nymphs （including those starved to empty their guts）; （ii） compare Stenoscepa sp. nymphs against other grasshoppers in the same habitat for whole-body metal concentrations; and （iii）compare the suitability of Ni hyperaccumulator and Ni accumulator plants as food sources for Stenoscepa sp. and other grasshoppers. Stenoscepa nymphs had extremely high whole-body Ni concentrations （3 500μg Ni/g）. This was partly due to food in the gut, as starved insects contained less Ni （950 pg Ni/g）. Stenoscepa nymphs survived significantly better than other grasshoppers collected from either a serpentine or a non-serpentine site when offered high-Ni plants as food. In a host preference test among four Berkheya species （two Ni hyperaccumulators and two Ni accumulators）, Stenoscepa sp, preferred leaves of the Ni hyperaccumulator species. A preference experiment using leaves of three Senecio species （of which one species, Senecio coronatus, was represented by both a Ni hyperaccumulator and a Ni accumulator population） showed that Stenoscepa sp. preferred Ni accumulator Senecio coronatus leaves to all other choices. We conclude that Stenoscepa sp. is extremely Ni-tolerant. Stenoscepa sp. nymphs prefer leaves of hyperaccumulator Berkheya species, but elevated Ni concentration alone does not determine their food preference. We suggest that the extremely high whole-body Ni concentration of Stenoscepa nymphs may affect food web relationships in these serpentine communities.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.
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.
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.
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 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.
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.
文摘Neptunia amplexicaulis is an herbaceous legume endemic to the Richmond area in central Queensland,Australia and is one of the strongest known Selenium hyperaccumulators on earth,showing significant potential to be utilised in Se phytoextraction applications.Here a protocol was established for in vitro micropropagation of Se hyperaccumula-tor N.amplexicaulis using nodal segments from in vitro-germinated seedlings.Shoot multiplication was achieved on Murashige and Skoog(MS)basal media supplemented with various concentrations of 6-Benzylaminopurine(BA)(1.0,2.0,3.0 mg L^(−1))alone or in combination with low levels of Naphthaleneacetic acid(NAA)(0.1,0.2,0.3 mg L^(−1)),with 2.0 mg L^(−1) BA+0.2 mg L^(−1) NAA found to be most effective.Elongated shoots were rooted in vitro using NAA,with highest root induction rate of 30%observed at 0.2 mg L^(−1) NAA.About 95%of the in vitro rooted shoots survived acclimatization.Clonally propagated plantlets were dosed with selenate/selenite solution and assessed for Se tissue concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy(ICP-AES)and found to retain their ability to hyperaccumulate.The protocol developed for this study has potential to be optimised for generating clonal plants of N.amplexicaulis for use in research and phytoextraction industry applications.
基金The International Office of Leibniz University Hannover(Germany)secured the Erasmus+“Mix IT”grant for the internship of Bennet BuhmannThis publication is part of the project“Living on the edge:unravelling the secrets of selenium hyperaccumulator plants”(with project number VI.Vidi.213.037)of the research programme ENW-VIDI which is(partly)financed by the Dutch Research Council(NWO).
文摘The trace element selenium is essential for human nutrition but is distributed unevenly in soils worldwide with exten-sive selenium-deficient regions and selenium-enriched(seleniferous)areas.Neptunia amplexicaulis is one of the strongest selenium hyperaccumulator plants known and native to Australian seleniferous soils.Research in the genetic background of the selenium accumulation and tolerance mechanisms of this species lacks biotech-nological and molecular tools for functional genetics.Therefore,this study aimed to develop a de novo shoot regen-eration protocol for N.amplexicaulis and validate an selenium accumulation test system.Callus was induced on root and hypocotyl explants excised from 5-day old seedlings and cultured on an adjusted MS medium(SIM9)containing 4.5 μM Thidiazuron(TDZ)for two weeks in darkness.After this period,the TDZ concentration was reduced to 0.45 μM,and the explants were transferred to light conditions.In addition,seedlings of N.amplexicaulis,N.heliophila and Med-icago truncatula were placed on vertical MS agar plates containing 1.5 mM(standard)or 0.1 mM(low)magnesium sulphate with 0,30,90 μM sodium selenate.Initial shoot differentiation was observed 6 weeks after culture initia-tion.This regeneration response was successfully repeated in a second experiment.The outgrow of the shoot buds into complete shoots was not yet achieved but requires additional media optimization.Additionally,spontaneous shoot regeneration from a root was observed,highlighting potential for further studies.In vitro grown seedlings dem-onstrated efficient,selective selenium uptake in N.amplexicaulis and identified M.truncatula as a secondary selenium accumulator with selenium concentrations of>300 μg Se g^(-1) DM.This project presents the first protocol for inducing early stages of development of indirect shoot organogenesis in N.amplexicaulis from hypocotyl and root explants as prerequisite for genetic transformation,though completing the regeneration cycle remains challenging.Neptunia amplexicaulis hyperaccumulates selenium also under in vitro conditions.
基金Sri Ramaswamy Memorial University,Andhra Pradesh,India for providing fellowship。
文摘Coal mining activities significantly impact the environment through water,soil,and air pollution of the surrounding areas.The dispersal of pollutants and the degradation of soil quality by toxic metals emitted from coal mining activities cause significant concerns worldwide,posing serious risks to ecosystems,human health,and vegetation.Restoration of quality of soil contaminated by toxic metals from coal mining is challenging due to the continuous increase in the concentration of toxic metals such as lead,copper,chromium,cadmium,and arsenic within the soil matrix.Conventional approaches utilized for the remediation of soil are often time-consuming and labour-intensive.In addition,they may lead to secondary pollution,particularly when applied at a large scale.Phytoremediation,a technique that utilizes plants with high metal accumulation capacity,has surfaced as a promising,eco-friendly strategy for remediating soil contaminated with toxic metals.These plants can absorb and sequester metals into above-and belowground tissues or stabilize them into less bioavailable forms within the rhizosphere.Species from families such as Brassicaceae and Asteraceae have demonstrated notable effectiveness in phytoremediation applications.The efficiency of phytoremediation can be further enhanced by applying organic and inorganic soil amendments to increase metal bioavailability and plant uptake.Moreover,genetic engineering has enabled the development of plants with improved metal tolerance and accumulation capacities.Complementing these approaches,microbial phytoremediation employs plant-associated microbes to facilitate metal uptake and transformation,increasing the overall remediation efficiency.Following remediation,biomass is proposed for value-added applications,including biochar,biogas,and recovery of metals for industrial reuse.This review summarizes the current progress,emerging strategies,and future prospects of phytoremediation for mitigating toxic metal pollution in coal mining-affected soils.Altogether,these approaches illustrate the potential of integrating circular bioeconomy principles in transforming phytoremediation as a sustainable strategy for mitigating toxic metal pollution in coal mining regions.
基金The work was jointly supported by the National High-tech R & D Program (Grant No. 2001AA640501)Chinese Academy of Sciences Innovation Program (Grant No. KZCX-401-01)the National Natural Science Foundation of China (Grant No. 40071075) and the Nat
文摘Pot experiment was conducted to understand the effect of phosphorus on arsenic accumulation in As-hyperaccumulator Chinese brake (Pteris vittata L.). It is shown that arsenic concentrations in the fronds and rhizoids, the arsenic bioaccumulation factor, and the total arsenic in the fronds were not influenced significantly under low levels of phosphorus (≤400 mg/kg) and increased sharply under high levels of phosphorus (】400 mg/ kg). The discovery implies that the efficiency of arsenic removal in phytoremedia-tion using the hyperaccumulating plant can be greatly elevated by the phosphorus addition at high rates. The interaction between the accumulation of phosphorus and that of arsenic in plant was stimulated mutually. The result represents that Chinese brake is a good material for plant physiologist to conduct comparative and mechanism studies on the uptake behaviors of phosphorus and arsenic, and phosphorus is also a potential accelerator for phytoremediation of arsenic-contaminated soils.
基金co-sponsored by the National Basic Science Research Program(2002CCA03800)National Natural Science Foundation of China(Grant No.40232002)Natural Science Foundation of Beijing(6990002).
文摘Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var ner-vosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2HAsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.
基金国家重点基础研究发展计划(973计划)，the Foundation of Excellent Young/Scientists of Shandong Province
文摘Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Moq.). K. folium and S. salsa had a NaCl content of 32.1% and 29.8%, respectively, on a dry weight basis. X-ray microanalysis of the Na+ in the vacuole, apoplasts and cytoplasm of the two plants indicated a ratio of 7.3:5.6:1.0 in K. folium and 7.3:6.6:1.0 in S. salsa. These data show that K. folium and S. salsa both have a high Na+ and Cl- accumulating capacity, which is related to high activity of tonoplast H+-ATPase and H+-PPase.
基金the National Basic Science Research Program(2002CCA03800)National Natural Science Foundation of China(Grant No.40232002)+1 种基金National Science Fund for Distinguished Young Scholars(Grant No.40325003)Beijing Synchrotron Radiation Facility(BSRF)at BEPC provided the facility for XRFmeasurement.
文摘The distributions of arsenic and 6 essential elements in the pinna of As hyperaccumulator,Pteris vittata L.,were studied using synchrotron radiation X-ray fluorescence(SRXRF).Significant correlation between the distribution and mobility of the elements revealed that SRXRF study on the elemental distribution was feasible to inspect the transportations of elements in plants.The distribution of As in the pinna showed that As had great abilities to be transported in xylem vessels and from xylem to mesophyll.The distribution of K,one of the most mobile elements in plants,was similar to that of As,whereas the distributions of Fe and Ca with less mobility in plants were almost opposite to that of As in the pinna.
基金supported by the National Natural Science Foundation of China(Nos.52000046,52100034,52170154,and 52070051)the Special Project of Guangxi Science and Technology Base and Talent(Nos.GuiKe AD20297009 and GuiKe AD20297007)the Middle-aged and Young Teachers’Basic Ability Promotion Project of Guangxi(Nos.2020KY05039 and 2021KY0221).
文摘Phytoextraction is a promising option for purifying hexavalent chromium(Cr(Ⅵ))-laden wastewater,but the long remediation period incurred by poor growth rate of Cr hyperaccumulators remains a primary hindrance to its large-scale application.In this study,we performed a hydroponic experiment to evaluate the feasibility of promoting the growth and phytoextraction efficiency of Cr hyperaccumulator Leersia hexandra Swartz(L.hexandra)by inoculating plant growth-promoting rhizobacteria(PGPR)Bacillus cereus(B.cereus).In batch tests,the Cr(Ⅵ)removal rates of L.hexandra and B.cereus co-culture were greater than the sum of their respective monocultures.This was likely due to the microbial reduction of Cr(Ⅵ)to Cr(Ⅲ),which is amiable to plant uptake.Besides,the PGPR factors of B.cereus,including indoleacetic acid(IAA)production,1-aminocyclopropane-1-carboxylic acid deamination(ACCd)activity,phosphate solubilization capacity,and siderophore production,were quantified.These PGPR factors helped explain the biomass augmentation,root elongation and enhanced Cr enrichment of the inoculated L.hexandra in pot experiments.Despite the increased Cr uptake,no aggravated oxidative damage to the cell membrane was observed in the inoculated L.hexandra.This was attributed to its capacity to confront the increased intracellular Cr stress by upregulating both the activities of antioxidative enzymes and expression of metal-binding proteins/peptides.Moreover,L.hexandra could always conserve the majority of Cr in the residual and oxalic integrated forms with low mobility and phytotoxicity,irrespective of the B.cereus inoculation.These results highlight the constructed Cr hyperaccumulatorrhizobacteria consortia as an effective candidate for decontaminating Cr(Ⅵ)-laden wastewater.
文摘The high levels of some metals in metal hyperaccumulator plants may be transferred to insect associates. We surveyed insects collected from the South African Ni hyperaccumulator Berkheya coddii to document whole-body metal concentrations （Co, Cr, Cu, Mg, Mn, Ni, Pb, Zn）. We also documented the concentrations of these metals in leaves, stems and inflorescences, finding extremely elevated levels of Ni （4 700-16 000μg/g） and high values （5-34μg/g） for Co, Cr, and Pb. Of 26 insect morphotypes collected from B. coddii, seven heteropterans, one coleopteran, and one orthopteran contained relatively high concentrations of Ni （〉 500μg/g）. The large number of high-Ni heteropterans adds to discoveries of others （from California USA and New Caledonia） and suggests that members of this insect order may be particularly Ni tolerant. Nymphs of the orthopteran （Stenoscepa） contained 3 500 μg Ni/g, the greatest Ni concentration yet reported for an insect. We also found two beetles with elevated levels of Mg （〉 2 800 μg/g）, one beetle with elevated Cu （〉 70 μg/g） and one heteropteran with an elevated level of Mn （〉 200 μg/g）. Our results show that insects feeding on a Ni hyperaccumulator can mobilize Ni into food webs, although we found no evidence of Ni biomagnification in either herbivore or carnivore insect taxa. We also conclude that some insects associated with hyperaccumulators can contain Ni levels that are high enough to be toxic to vertebrates.
文摘Arthropods （mainly insects） were collected from a forest site that contained at least six species of Ni hyperaccumulators. Whole body Ni analysis was performed for 12 arthropod taxa, two of which were studied at different life cycle stages. We found two Nitolerant insects. The pentatomid heteropteran Utana viridipuncta, feeding on fruits of the Ni hyperaccumulator Hybanthus austrocaledonicus, contained a mean of 2 600 μg Ni/g in nymphs and 750μg Ni/g in adults. The tephritid fly Bactrocera psidii, feeding on pulp of Sebertia acuminata fruits that contained 6 900μg Ni/g, contained 420μg Ni/g as larvae that had evacuated their guts and significantly less （65μg Ni/g） as adults. European honeybees （Apis mellifera） visiting flowers of the Ni hyperaccumulator H. austrocaledonicus contained significantly more Ni （8-fold more） than those collected from flowers of Myodocarpus fraxinifolius, a non-hyperaccumulator. Our results show that some insects feed on Ni hyperaccumulator plants and that their feeding mobilizes Ni into local food webs.
文摘Nymphs of Stenoscepa sp. feed on leaves of the Ni hyperaccumulator Berkheya coddii at serpentine sites in Mpumalanga Province, South Africa. These sites contain Ni hyperaccumulators, Ni accumulators, and plants with Ni concentrations in the normal range. We conducted studies to： （i） determine the whole-body metal concentration of nymphs （including those starved to empty their guts）; （ii） compare Stenoscepa sp. nymphs against other grasshoppers in the same habitat for whole-body metal concentrations; and （iii）compare the suitability of Ni hyperaccumulator and Ni accumulator plants as food sources for Stenoscepa sp. and other grasshoppers. Stenoscepa nymphs had extremely high whole-body Ni concentrations （3 500μg Ni/g）. This was partly due to food in the gut, as starved insects contained less Ni （950 pg Ni/g）. Stenoscepa nymphs survived significantly better than other grasshoppers collected from either a serpentine or a non-serpentine site when offered high-Ni plants as food. In a host preference test among four Berkheya species （two Ni hyperaccumulators and two Ni accumulators）, Stenoscepa sp, preferred leaves of the Ni hyperaccumulator species. A preference experiment using leaves of three Senecio species （of which one species, Senecio coronatus, was represented by both a Ni hyperaccumulator and a Ni accumulator population） showed that Stenoscepa sp. preferred Ni accumulator Senecio coronatus leaves to all other choices. We conclude that Stenoscepa sp. is extremely Ni-tolerant. Stenoscepa sp. nymphs prefer leaves of hyperaccumulator Berkheya species, but elevated Ni concentration alone does not determine their food preference. We suggest that the extremely high whole-body Ni concentration of Stenoscepa nymphs may affect food web relationships in these serpentine communities.
