Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elon...Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0.05 and 0 5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for roots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30261 mg/kg DW) at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni>Cu>Pb>Cd (mg/kg DW), and those in roots were Pb>Cd>Ni>Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing root exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb, a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no correlation between alternations in root exudation of organic acids and metal accumulation could be established.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
Heavy metals are widely distributed contaminants in natural environments and their potential threats to human health have attracted worldwide concerns due to the food chain. Therefore, great efforts have been made to ...Heavy metals are widely distributed contaminants in natural environments and their potential threats to human health have attracted worldwide concerns due to the food chain. Therefore, great efforts have been made to reduce them to a safe level in soil. Compared with the traditional methods, the method using plants to remove them has been accepted as a feasible and efficient way. Herein, the geochemical behavior of heavy metals and the restoration methods with phytoremediation were reviewed. In addition, issues on heavy metal speciation as well as its influencing factors, phytoremediation mechanism, phytoremediation effect and vegetation selection principle used for phytoremediation were discussed.展开更多
In this study,HPLC-MS and ICP-MS methods wereused for the determination of histidine and cadmiumin Eleagnusangustifolia L.,Vitisvinifera L.and Nerium oleander L.leaves taken from industrial area including Gaziantep an...In this study,HPLC-MS and ICP-MS methods wereused for the determination of histidine and cadmiumin Eleagnusangustifolia L.,Vitisvinifera L.and Nerium oleander L.leaves taken from industrial area including Gaziantep and Bursa cities.To histidine determination by HPLC-MS,flow rate of mobile phase,fragmentor potential,injection volume and column temperature were optimized as 0.2mL·min^(-1),70V,15μL and 20℃,respectively.For extraction of histidine from plants,distilled water was used by applying on 90℃and 30min.The concentrations(as mg·kg^(-1))of histidine were found to be in range of 8~22for Eleagnusangustifolia L.,10~33for Vitisvinifera L.and 6~11for Nerium oleander L.The concentrations of cadmium were found to be in ranges of 6~21μg·kg^(-1) for Vitisvinifera L.15~110μg·kg^(-1) for Eleagnusangustifolia L.and 63~218μg·kg^(-1) for Nerium oleander L.展开更多
Phytoremediation techniques to clean heavy metal pollution soil depend on identifying plant species that can act as phytoremediators.One important approach to screening potential phytoremediators is to evaluate charac...Phytoremediation techniques to clean heavy metal pollution soil depend on identifying plant species that can act as phytoremediators.One important approach to screening potential phytoremediators is to evaluate characteristics of heavy metal accumulation.In this study,we performed firsthand analysis of Cd tolerance and accumulation characteristics of three Sansevieria trifasciata cultivars by pot experiment.Plant growth results showed that all three S.trifasciata cultivars can tolerate 50 mg kg^-1 soil Cd concentration.After growth under 50 mg kg^-1 soil Cd concentration for 4 months,the Cd bioconcentration factors in the shoots of S.‘Trifasciata’,S.trifasciata‘Laurentii’,and S.trifasciata‘Silver Hahnii’were 1.26,1.30,and 1.19,while those in the roots were 12.53,11.43,and 5.45,respectively.This result reveals the considerably low translocation factors of 0.10,0.12,and 0.22 for S.‘Trifasciata’,S.trifasciata‘Laurentii’,and S.trifasciata‘Silver Hahnii’,respectively.These results suggest that all three S.trifasciata cultivars had high Cd absorption capacities but low Cd translocation capacities.In combination with total Cd accumulation distribution and plant growth characteristics,S.trifasciata can be designed as a phytostabilizer in Cd-contaminated soils in its cultivation regions.Meanwhile,the mechanism of high Cd tolerance and accumulation characteristics in the roots of S.trifasciata should be explored.This study provides new resources for dealing with Cd-contaminated soils and exploring Cd tolerance and accumulation mechanisms in plants.展开更多
Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of micro...Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of microorganisms and different plant species. In consideration of biomass, phytoremediation is a very useful techniques above all, can be exploit by identification of hyperaccumulator, which accumulates the heavy metal under metal stress condition. In view of constraints of efficient plant species in present study thirty seven different plant species were screened for the identification of heavy metal accumulators. Croton bonplandianum, sedges and Balanites aegyptiaca amongst the all exhibit superior potential of heavy metal accumulation. This is the first report to unravel the heavy metal accumulation property of three different plant species which can be exploited for the bioremediation of heavy metals.展开更多
Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteris...Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteristics of high environmental adaptation and barren resistance. Some varieties of pteridophyta have ability of excessive absorption and accumulation of heavy metals such as arsenic(As) and antimony(Sb). Besides,pteridophyta have excellent performance in absorbing such heavy metals as cadmium(Cd),lead(Pb),copper(Cu),and nickel(Ni),and rare earth elements. In this paper,a review was made for application,mechanism,and advantages of pteridophyta in remediation of heavy metal contaminated environments,and prospect and possible research fields of pteridophyta in phytoremediation were discussed.展开更多
A new way is described to recover nickel from common rock-types, by the use of nickel hyperaccumulator plants. The idea of phytomining nickel was suggested earlier, but never implemented. This situation may soon chang...A new way is described to recover nickel from common rock-types, by the use of nickel hyperaccumulator plants. The idea of phytomining nickel was suggested earlier, but never implemented. This situation may soon change, because the mining sector suffers from a poor image on account of the impact of mining on the environment, and would like to reduce the pollution and high energy consumption associated with metal extraction. Once phytomining is established as a viable way of nickel production, it is likely that governments will impose nickel mines to realize part of their nickel production by this method. This will lead to a considerable decrease of CO2 emissions. Phytomining from rocks rich in olivine or serpentine is CO2-negative. When metal extraction goes hand in hand with CO2 sequestration, it will improve the image of the mining sector. Other advantages include that unproductive soils can serve to grow nickel hyperaccumulator plants and recover nickel. The extensive mining technology can provide employment to many poor farmers/miners. Countries that want to be self-sufficient in strategic materials, and avoid spending foreign currency on importing them can switch to phytomining. This paper treats different aspects of future nickel farming.展开更多
At the present manuscript,a brief report is given concerning heavy metals soil bioremediation methods and particularly phytoextraction by means of hyper-accumulator plants.The picking of the plants i.e.Thlaspi caerule...At the present manuscript,a brief report is given concerning heavy metals soil bioremediation methods and particularly phytoextraction by means of hyper-accumulator plants.The picking of the plants i.e.Thlaspi caerulescens should meet certain requirements according to already conducted experiments.Cultivations’data of the aforementioned Cd and Zn phytoaccumulator species are demonstrated.The last part incorporates a case study of a heavy metal-contaminated area nearby an abandoned lead-zinc mine located somewhere in NE(Northeast)Greece and a fundamental operational&cost analysis of the whole remediation project.展开更多
Lead (Pb) tolerance and phytoextraction efficiency of arum (Pani Kachu;Colocasia esculenta L.) were investigated in hydroponics. Plants were grown for 60 days in nutrient solution after addition of Pb at the levels of...Lead (Pb) tolerance and phytoextraction efficiency of arum (Pani Kachu;Colocasia esculenta L.) were investigated in hydroponics. Plants were grown for 60 days in nutrient solution after addition of Pb at the levels of 0, 50, 200 and 400 μM. The growth of different parts of arum was unaffected at low level of Pb concentration (50 μM Pb) compared with control treatment whereas it decreased gradually with the increase of metal concentration in nutrient solution. Concentration of metal in all parts of arum increased significantly with the levels of Pb in the growth media (p ·kg<sup>ǃ</sup>, at its low level in solution. This concentration (50 μM Pb) did not cause any growth retardation which indicated that arum was a Pb hyperaccumulator plant. On an average, translocation of Pb from roots to shoots was 68% of total Pb which indicated that the major portion of Pb was translocated from roots to shoots. Transfer factor (TF) greater than one for this metal as found in the present experiment confirmed the hyperaccumulation characteristics of arum. Lead uptake in the shoots of arum without growth retardation and TF of Pb in arum indicated that this plant was a suitable candidate for the phytoremediation of soil and water contaminated with Pb.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
Environmental scanning electron microscope (ESEM) fitted with an energy disper- sive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arse- nic (As) micro-distribution in Chinese brake...Environmental scanning electron microscope (ESEM) fitted with an energy disper- sive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arse- nic (As) micro-distribution in Chinese brake (Pteris vittata L.). It was found that amounts of trichome, which possessed multicellular structure with the average length of 160 μm and with an average diameter of 28 μm, existed in the frond of P. vittata, and the density of trichome on the pinnate axial surface was higher than that on the petiole. Visible X-ray peak of As was recorded in the epidermal cell and trichome. The relative weight of As in the pinnate trichome, which con- tained the highest concentration of As among all tissues of the plant, was 2.4 and 3.9 times as much as that in the epidermal and mesophyllous cells, respectively. The As concentrations in the basal and stalk cells of the same trichome were higher than that in its cap cell. This is the first time to report that the trichome of P. vittata plays an important role in arsenic hyperaccumulation. The finding from the present study implies that much attention should be paid to the role of the trichome in understanding the hyperaccumulation and detoxicity of As in the hyperaccumulator and improving the ability of As accumulation.展开更多
Aims the functional advantages of arsenic(As)hyperaccumulation by plants are poorly understood.One proposed benefit,termed ele-mental allelopathy,occurs when hyperaccumulated As is cycled from the plant back into the ...Aims the functional advantages of arsenic(As)hyperaccumulation by plants are poorly understood.One proposed benefit,termed ele-mental allelopathy,occurs when hyperaccumulated As is cycled from the plant back into the top layer of soil,allowing As hyperaccu-mulators to gain an advantage over intolerant species by increasing soil As concentrations([As])underneath their canopy.to date,there are no studies that detail the presence of increased soil[As]associ-ated with As hyperaccumulators.In this study,we documented vari-ation in the soil[As]associated with the Chinese brake fern,Pteris vittata L.and also compared the effects of environmentally relevant soil and solution[As]on competitor plant growth.Methods Four populations of P.vittata were identified in central Florida,USA.P.vittata tissue samples and soil samples were collected at the base of and at 3 m away from ferns in each population(n=36).Five sample locations were randomly selected from each site,and soils from the base and 3 m away from each fern were collected to examine the effects of naturally occurring soil[As]on the germination and growth of a potential competitor plant(Oxalis stricta).Solutions with increasing[As]were also used to examine the threshold for negative effects of[As]on O.stricta growth.[As]were measured using inductively coupled plasma mass spectrometry(ICP-MS).Important Findings Overall,soil[As]from the base of ferns was nearly twice that of soil 3 m away indicating that ferns hyperaccumulate As.However,ferns and their associated soil,contained different[As]depending on their col-lection site,indicating that these populations accumulate and use[As]differently.O.stricta growth decreased and germination was delayed as solution and soil[As]increased.However,the relative distance from the fern that the soil was collected from did not affect growth,which would be expected with elemental allelopathy.Our results show that P.vittata is associated with higher soil[As]and these concentrations are sufficient to inhibit growth of competitors.However,the absence of a strong inhibitory relationship associated with proximity to the fern across all locations suggests that the possible functional advantages of elemental allelopathy may depend on site specific characteristics.展开更多
Aims The Inclusive Niche Hypothesis has not been validated for plants using ecophysiological performance.The few experiments have measured growth and competition but not the physiological response of plants.A metallop...Aims The Inclusive Niche Hypothesis has not been validated for plants using ecophysiological performance.The few experiments have measured growth and competition but not the physiological response of plants.A metallophyte plant that hyperaccumulates aluminium(Al),Plantago almogravensis,showed a defined spa-tial distribution by occurring mostly on vegetation gaps associ-ated with metalliferous areas(geochemical islands).This case was used to determine,in situ,whether the Inclusive Niche Hypothesis was suitable to explain the extent of the species real-ized niche.Methods The vegetation associated with P.almogravensis geochemical islands in the SW coast of Portugal was mapped.The biotic(neighbouring plants)and abiotic(edaphic)components of the niche were cor-related with parameters of the plant’s ecological and physiological performances(plant density and cover;leaf C and N concentration and isotopic composition;growth).The results were obtained using image analysis,abundance and morphological measures,isotopic signatures and chemical composition.Important Findings The species showed better physiological performance where its ecological performance was lower due to trade-offs with environ-mental constraints.The species’realized niche was mostly limited by shrub competition and soil Al-toxicity.These limits contribute to explain the rarity status of the species:the species has a poor capacity to compete but,due to an enhanced Al-tolerance and Al-hyperaccumulator trait,has the ability to find refuge in geochem-ical islands that are too harsh for most other species.This work,based on ecophysiological field studies,provides support for the Inclusive Niche Hypothesis relating to plant species.展开更多
Field survey and greenhouse experiments were carried out to identify and characterize zinc (Zn) uptake and accumulation by a new Zn hyperaccumulating plant species (Sedum alfredii Hance) native to China. Zinc concentr...Field survey and greenhouse experiments were carried out to identify and characterize zinc (Zn) uptake and accumulation by a new Zn hyperaccumulating plant species (Sedum alfredii Hance) native to China. Zinc concentration in the shoots of Sedum alfredii Hance grown on an ancient mined area ranged from 4134 to 5000 mg/kg, with a mean of 4515 mg/kg. It suggests that Sedum alfredii could not only grow on heavily Pb/Zn contaminated soils, but also could accumulate extraordinarily high concentration of Zn. Under nutrient solution culture conditions, Sedum alfredii Hance grew healthy at Zn supplying levels from 0.006 to 240 mg · L-1. Zinc concentration in the shoots increased with external Zn levels increasing. The Zn concentration and accumulation in the shoots reached the highest at Zn supply level of SO mg/L, with 19.67 g/kg and 19.83 nig/plant, respectively. All the results showed that Sedum alfredii Hance is a new Zn hyperaccumulating plant. This provides a new plant material to explore mechanism of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
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 di...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
Sedum alfredii Hance is a cadmium(Cd)/zinc(Zn)hyperaccumulator native to China.However,its relatively low biomass restricted the large-scale application for heavy metal contamination remediation.The chromosome set dou...Sedum alfredii Hance is a cadmium(Cd)/zinc(Zn)hyperaccumulator native to China.However,its relatively low biomass restricted the large-scale application for heavy metal contamination remediation.The chromosome set doubling of S.alfredii in vitro was achieved by 0.1%–0.2%(W/V)colchicine treatment.The plant DNA ploidy was analyzed by flow cytometry and chromosome set doubling plants(CSD)were identified based on the obvious different sharp peak.A tissue culture experiment with different Cd treated levels and a field trial with natural polluted mined soil were conducted to study the effects of chromosome doubling on plant biomass and Cd accumulation in shoots.The results suggested that S.alfredii is a mixoploid.Compared with the wild type plants(WT),CSD exhibited typical"gigas"characteristics in morphology including stem thickness,root hair production,number of leaves and size of stoma guard cell.Fresh weight and dry weight of CSD were increased to 1.62–2.03-fold and 2.26–3.25-fold of WT.And Cd content of CSD showed a17.49%–42.82%increase and 59%increase under tissue culture and field condition,accordingly.In addition,the TF and in BCF of CSD were 2.37-and 1.59-fold of WT,respectively.These results proved that it is feasible to promote phytoextraction efficiency of S.alfredii in Cd contaminated soils through chromosomal engineering,which provides a novel approach for hyperaccumulator application in phytoremediation.展开更多
文摘Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0.05 and 0 5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for roots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30261 mg/kg DW) at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni>Cu>Pb>Cd (mg/kg DW), and those in roots were Pb>Cd>Ni>Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing root exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb, a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no correlation between alternations in root exudation of organic acids and metal accumulation could be established.
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financially supported by the Special Fund of Shaanxi Education Department (18JK0172)the Initial Funding of Talent in Shaanxi University of Technology (SLGQD201702)
文摘Heavy metals are widely distributed contaminants in natural environments and their potential threats to human health have attracted worldwide concerns due to the food chain. Therefore, great efforts have been made to reduce them to a safe level in soil. Compared with the traditional methods, the method using plants to remove them has been accepted as a feasible and efficient way. Herein, the geochemical behavior of heavy metals and the restoration methods with phytoremediation were reviewed. In addition, issues on heavy metal speciation as well as its influencing factors, phytoremediation mechanism, phytoremediation effect and vegetation selection principle used for phytoremediation were discussed.
基金financially supported by the Scientific Investigate Projects of Firat University,Turkey(Project Number:FF.11.19)
文摘In this study,HPLC-MS and ICP-MS methods wereused for the determination of histidine and cadmiumin Eleagnusangustifolia L.,Vitisvinifera L.and Nerium oleander L.leaves taken from industrial area including Gaziantep and Bursa cities.To histidine determination by HPLC-MS,flow rate of mobile phase,fragmentor potential,injection volume and column temperature were optimized as 0.2mL·min^(-1),70V,15μL and 20℃,respectively.For extraction of histidine from plants,distilled water was used by applying on 90℃and 30min.The concentrations(as mg·kg^(-1))of histidine were found to be in range of 8~22for Eleagnusangustifolia L.,10~33for Vitisvinifera L.and 6~11for Nerium oleander L.The concentrations of cadmium were found to be in ranges of 6~21μg·kg^(-1) for Vitisvinifera L.15~110μg·kg^(-1) for Eleagnusangustifolia L.and 63~218μg·kg^(-1) for Nerium oleander L.
基金This work was financially supported by the Youth Innovation Promotion Association CAS(2020387).
文摘Phytoremediation techniques to clean heavy metal pollution soil depend on identifying plant species that can act as phytoremediators.One important approach to screening potential phytoremediators is to evaluate characteristics of heavy metal accumulation.In this study,we performed firsthand analysis of Cd tolerance and accumulation characteristics of three Sansevieria trifasciata cultivars by pot experiment.Plant growth results showed that all three S.trifasciata cultivars can tolerate 50 mg kg^-1 soil Cd concentration.After growth under 50 mg kg^-1 soil Cd concentration for 4 months,the Cd bioconcentration factors in the shoots of S.‘Trifasciata’,S.trifasciata‘Laurentii’,and S.trifasciata‘Silver Hahnii’were 1.26,1.30,and 1.19,while those in the roots were 12.53,11.43,and 5.45,respectively.This result reveals the considerably low translocation factors of 0.10,0.12,and 0.22 for S.‘Trifasciata’,S.trifasciata‘Laurentii’,and S.trifasciata‘Silver Hahnii’,respectively.These results suggest that all three S.trifasciata cultivars had high Cd absorption capacities but low Cd translocation capacities.In combination with total Cd accumulation distribution and plant growth characteristics,S.trifasciata can be designed as a phytostabilizer in Cd-contaminated soils in its cultivation regions.Meanwhile,the mechanism of high Cd tolerance and accumulation characteristics in the roots of S.trifasciata should be explored.This study provides new resources for dealing with Cd-contaminated soils and exploring Cd tolerance and accumulation mechanisms in plants.
文摘Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of microorganisms and different plant species. In consideration of biomass, phytoremediation is a very useful techniques above all, can be exploit by identification of hyperaccumulator, which accumulates the heavy metal under metal stress condition. In view of constraints of efficient plant species in present study thirty seven different plant species were screened for the identification of heavy metal accumulators. Croton bonplandianum, sedges and Balanites aegyptiaca amongst the all exhibit superior potential of heavy metal accumulation. This is the first report to unravel the heavy metal accumulation property of three different plant species which can be exploited for the bioremediation of heavy metals.
基金Supported by Scientific Research Foundation of Yunnan Provincial Department of Education(2015Y296)Construction Project of Key Superior and Characteristic Disciplines in Colleges and Universities of Yunnan Province
文摘Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteristics of high environmental adaptation and barren resistance. Some varieties of pteridophyta have ability of excessive absorption and accumulation of heavy metals such as arsenic(As) and antimony(Sb). Besides,pteridophyta have excellent performance in absorbing such heavy metals as cadmium(Cd),lead(Pb),copper(Cu),and nickel(Ni),and rare earth elements. In this paper,a review was made for application,mechanism,and advantages of pteridophyta in remediation of heavy metal contaminated environments,and prospect and possible research fields of pteridophyta in phytoremediation were discussed.
文摘A new way is described to recover nickel from common rock-types, by the use of nickel hyperaccumulator plants. The idea of phytomining nickel was suggested earlier, but never implemented. This situation may soon change, because the mining sector suffers from a poor image on account of the impact of mining on the environment, and would like to reduce the pollution and high energy consumption associated with metal extraction. Once phytomining is established as a viable way of nickel production, it is likely that governments will impose nickel mines to realize part of their nickel production by this method. This will lead to a considerable decrease of CO2 emissions. Phytomining from rocks rich in olivine or serpentine is CO2-negative. When metal extraction goes hand in hand with CO2 sequestration, it will improve the image of the mining sector. Other advantages include that unproductive soils can serve to grow nickel hyperaccumulator plants and recover nickel. The extensive mining technology can provide employment to many poor farmers/miners. Countries that want to be self-sufficient in strategic materials, and avoid spending foreign currency on importing them can switch to phytomining. This paper treats different aspects of future nickel farming.
文摘At the present manuscript,a brief report is given concerning heavy metals soil bioremediation methods and particularly phytoextraction by means of hyper-accumulator plants.The picking of the plants i.e.Thlaspi caerulescens should meet certain requirements according to already conducted experiments.Cultivations’data of the aforementioned Cd and Zn phytoaccumulator species are demonstrated.The last part incorporates a case study of a heavy metal-contaminated area nearby an abandoned lead-zinc mine located somewhere in NE(Northeast)Greece and a fundamental operational&cost analysis of the whole remediation project.
文摘Lead (Pb) tolerance and phytoextraction efficiency of arum (Pani Kachu;Colocasia esculenta L.) were investigated in hydroponics. Plants were grown for 60 days in nutrient solution after addition of Pb at the levels of 0, 50, 200 and 400 μM. The growth of different parts of arum was unaffected at low level of Pb concentration (50 μM Pb) compared with control treatment whereas it decreased gradually with the increase of metal concentration in nutrient solution. Concentration of metal in all parts of arum increased significantly with the levels of Pb in the growth media (p ·kg<sup>ǃ</sup>, at its low level in solution. This concentration (50 μM Pb) did not cause any growth retardation which indicated that arum was a Pb hyperaccumulator plant. On an average, translocation of Pb from roots to shoots was 68% of total Pb which indicated that the major portion of Pb was translocated from roots to shoots. Transfer factor (TF) greater than one for this metal as found in the present experiment confirmed the hyperaccumulation characteristics of arum. Lead uptake in the shoots of arum without growth retardation and TF of Pb in arum indicated that this plant was a suitable candidate for the phytoremediation of soil and water contaminated with Pb.
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.
基金This work was supported by the National Science Fund for Distinguished Young Scholar(Grant No.40325003)the China State Program for Basic Research(No.2002CCA03800)+1 种基金the National Natural Science Foundation of China(Grant No.40232022)the National High-Tech R&D Program(No.2001AA6450).
文摘Environmental scanning electron microscope (ESEM) fitted with an energy disper- sive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arse- nic (As) micro-distribution in Chinese brake (Pteris vittata L.). It was found that amounts of trichome, which possessed multicellular structure with the average length of 160 μm and with an average diameter of 28 μm, existed in the frond of P. vittata, and the density of trichome on the pinnate axial surface was higher than that on the petiole. Visible X-ray peak of As was recorded in the epidermal cell and trichome. The relative weight of As in the pinnate trichome, which con- tained the highest concentration of As among all tissues of the plant, was 2.4 and 3.9 times as much as that in the epidermal and mesophyllous cells, respectively. The As concentrations in the basal and stalk cells of the same trichome were higher than that in its cap cell. This is the first time to report that the trichome of P. vittata plays an important role in arsenic hyperaccumulation. The finding from the present study implies that much attention should be paid to the role of the trichome in understanding the hyperaccumulation and detoxicity of As in the hyperaccumulator and improving the ability of As accumulation.
文摘Aims the functional advantages of arsenic(As)hyperaccumulation by plants are poorly understood.One proposed benefit,termed ele-mental allelopathy,occurs when hyperaccumulated As is cycled from the plant back into the top layer of soil,allowing As hyperaccu-mulators to gain an advantage over intolerant species by increasing soil As concentrations([As])underneath their canopy.to date,there are no studies that detail the presence of increased soil[As]associ-ated with As hyperaccumulators.In this study,we documented vari-ation in the soil[As]associated with the Chinese brake fern,Pteris vittata L.and also compared the effects of environmentally relevant soil and solution[As]on competitor plant growth.Methods Four populations of P.vittata were identified in central Florida,USA.P.vittata tissue samples and soil samples were collected at the base of and at 3 m away from ferns in each population(n=36).Five sample locations were randomly selected from each site,and soils from the base and 3 m away from each fern were collected to examine the effects of naturally occurring soil[As]on the germination and growth of a potential competitor plant(Oxalis stricta).Solutions with increasing[As]were also used to examine the threshold for negative effects of[As]on O.stricta growth.[As]were measured using inductively coupled plasma mass spectrometry(ICP-MS).Important Findings Overall,soil[As]from the base of ferns was nearly twice that of soil 3 m away indicating that ferns hyperaccumulate As.However,ferns and their associated soil,contained different[As]depending on their col-lection site,indicating that these populations accumulate and use[As]differently.O.stricta growth decreased and germination was delayed as solution and soil[As]increased.However,the relative distance from the fern that the soil was collected from did not affect growth,which would be expected with elemental allelopathy.Our results show that P.vittata is associated with higher soil[As]and these concentrations are sufficient to inhibit growth of competitors.However,the absence of a strong inhibitory relationship associated with proximity to the fern across all locations suggests that the possible functional advantages of elemental allelopathy may depend on site specific characteristics.
基金Fundação para a Ciência e Tecnologia(FCT)through project ECODILEMA(POCTI/BIA-BDE/60664/2004 and PPCDT/BIA-BDE/60664/2004)C.B.acknowledges a Investigador FCT contract and H.C.S.acknowledges the PhD grant(SFRH/BD/38289/2007)from FCT。
文摘Aims The Inclusive Niche Hypothesis has not been validated for plants using ecophysiological performance.The few experiments have measured growth and competition but not the physiological response of plants.A metallophyte plant that hyperaccumulates aluminium(Al),Plantago almogravensis,showed a defined spa-tial distribution by occurring mostly on vegetation gaps associ-ated with metalliferous areas(geochemical islands).This case was used to determine,in situ,whether the Inclusive Niche Hypothesis was suitable to explain the extent of the species real-ized niche.Methods The vegetation associated with P.almogravensis geochemical islands in the SW coast of Portugal was mapped.The biotic(neighbouring plants)and abiotic(edaphic)components of the niche were cor-related with parameters of the plant’s ecological and physiological performances(plant density and cover;leaf C and N concentration and isotopic composition;growth).The results were obtained using image analysis,abundance and morphological measures,isotopic signatures and chemical composition.Important Findings The species showed better physiological performance where its ecological performance was lower due to trade-offs with environ-mental constraints.The species’realized niche was mostly limited by shrub competition and soil Al-toxicity.These limits contribute to explain the rarity status of the species:the species has a poor capacity to compete but,due to an enhanced Al-tolerance and Al-hyperaccumulator trait,has the ability to find refuge in geochem-ical islands that are too harsh for most other species.This work,based on ecophysiological field studies,provides support for the Inclusive Niche Hypothesis relating to plant species.
基金This work was supported by the Outstanding Young Scientist Program of the National Natural Science Foundation of China (Grant No. 39925024).
文摘Field survey and greenhouse experiments were carried out to identify and characterize zinc (Zn) uptake and accumulation by a new Zn hyperaccumulating plant species (Sedum alfredii Hance) native to China. Zinc concentration in the shoots of Sedum alfredii Hance grown on an ancient mined area ranged from 4134 to 5000 mg/kg, with a mean of 4515 mg/kg. It suggests that Sedum alfredii could not only grow on heavily Pb/Zn contaminated soils, but also could accumulate extraordinarily high concentration of Zn. Under nutrient solution culture conditions, Sedum alfredii Hance grew healthy at Zn supplying levels from 0.006 to 240 mg · L-1. Zinc concentration in the shoots increased with external Zn levels increasing. The Zn concentration and accumulation in the shoots reached the highest at Zn supply level of SO mg/L, with 19.67 g/kg and 19.83 nig/plant, respectively. All the results showed that Sedum alfredii Hance is a new Zn hyperaccumulating plant. This provides a new plant material to explore mechanism of
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.
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 Key Research and Development Project of China (No. 2016YFD0800801)the National Natural Science Foundation of China (No. 41771345)the Fundamental Research Funds for the Central Universities (2019FZJD007)
文摘Sedum alfredii Hance is a cadmium(Cd)/zinc(Zn)hyperaccumulator native to China.However,its relatively low biomass restricted the large-scale application for heavy metal contamination remediation.The chromosome set doubling of S.alfredii in vitro was achieved by 0.1%–0.2%(W/V)colchicine treatment.The plant DNA ploidy was analyzed by flow cytometry and chromosome set doubling plants(CSD)were identified based on the obvious different sharp peak.A tissue culture experiment with different Cd treated levels and a field trial with natural polluted mined soil were conducted to study the effects of chromosome doubling on plant biomass and Cd accumulation in shoots.The results suggested that S.alfredii is a mixoploid.Compared with the wild type plants(WT),CSD exhibited typical"gigas"characteristics in morphology including stem thickness,root hair production,number of leaves and size of stoma guard cell.Fresh weight and dry weight of CSD were increased to 1.62–2.03-fold and 2.26–3.25-fold of WT.And Cd content of CSD showed a17.49%–42.82%increase and 59%increase under tissue culture and field condition,accordingly.In addition,the TF and in BCF of CSD were 2.37-and 1.59-fold of WT,respectively.These results proved that it is feasible to promote phytoextraction efficiency of S.alfredii in Cd contaminated soils through chromosomal engineering,which provides a novel approach for hyperaccumulator application in phytoremediation.
