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Zhihong Ye - One of the best experts on this subject based on the ideXlab platform.
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antioxidant enzymes and proteins of Wetland Plants their relation to pb tolerance and accumulation
Environmental Science and Pollution Research, 2015Co-Authors: Junxing Yang, Zhihong YeAbstract:Constructed Wetlands used to clean up toxic metals such as lead (Pb) from contaminated wastewater are considered as an effective and low-cost technology. The effect of Pb on the biomass, tolerance, soluble protein, and antioxidant enzymes in 18 candidate Wetland plant species grown in soils without (control) and spiked with 900 and 1800 mg Pb kg(-1) was studied in a pot trial. Our pot experiment showed that the biomass, tolerance, and leaf protein contents decreased with increasing concentrations of Pb in soil. There were significant differences between the Plants in their Pb tolerance indices (29-82 % in the 900 mg Pb kg(-1) amended soil) and also Pb uptake (13-749 mg kg(-1) in shoots and 1112-4891 mg kg(-1) in roots, in the same treatments). Activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of most of the Plants increased with increasing level of soil Pb concentration. Conversely, catalase (CAT) activity in leaves declined when Plants were subjected to Pb stress. Lead accumulation by the 18 Wetland plant species screened was strongly dependent on the species and Pb concentrations in the soil. However, Pb translocation from root to shoot was generally low in all species. Increases in SOD and POD activities suggest that the antioxidant system may play an important role in alleviating Pb toxicity in Wetland Plants. The data obtained should help in future species selection for the use in designing Wetlands in Pb-contaminated environments.
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root porosity radial oxygen loss and iron plaque on roots of Wetland Plants in relation to zinc tolerance and accumulation
Plant and Soil, 2014Co-Authors: Junxing Yang, Zhihong YeAbstract:Background and aims Wetland Plants have been widely used in constructed Wetlands for the clean-up of metal-contaminated waters. This study investigated the relationship between rate of radial oxygen loss (ROL), root porosity, Zn uptake and tolerance, Fe plaque formation in Wetland Plants.
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root porosity and radial oxygen loss related to arsenic tolerance and uptake in Wetland Plants
Environmental Pollution, 2011Co-Authors: Zhihong Ye, Huiyao Li, M H WongAbstract:Abstract The rates of radial oxygen loss (ROL), root porosity, concentrations of arsenic (As), iron (Fe) and manganese (Mn) in shoot and root tissues and on root surfaces, As tolerances, and their relationships in different Wetland Plants were investigated based on a hydroponic experiment (control, 0.8, 1.6 mg As L −1 ) and a soil pot trail (control, 60 mg As kg −1 ). The results revealed that Wetland Plants showed great differences in root porosity (9–64%), rates of ROL (55–1750 mmo1 O 2 kg −1 root d.w. d −1 ), As uptake (e.g., 8.8–151 mg kg −1 in shoots in 0.8 mg As L −1 treatment), translocation factor (2.1–47% in 0.8 mg As L −1 ) and tolerance (29–106% in 0.8 mg As L −1 ). Wetland Plants with higher rates of ROL and root porosity tended to form more Fe/Mn plaque, possess higher As tolerance, higher concentrations of As on root surfaces and a lower As translocation factor so decreasing As toxicity.
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Metal accumulation and tolerance in Wetland Plants
Frontiers of Biology in China, 2009Co-Authors: Junxing Yang, Zhihong YeAbstract:This paper briefly reviews the progress in studies of Wetland Plants in terms of heavy metal pollution. The current research mainly includes the following areas: (1) metal uptake, translocation, and distributions in Wetland Plants and toxicological effects on Wetland Plants, (2) radial oxygen loss (ROL) of Wetland Plants and its effects on metal mobility in rhizosphere soils, (3) constitutional metal tolerance in Wetland Plants, and (4) mechanisms of metal tolerance by Wetland Plants. Although a number of accomplishments have been achieved, many issues still remain unanswered. The future research effort is likely to focus on the ROL of Wetland Plants affecting metal speciation and bioavailability in rhizosphere soils, and the development of rhizosphere management technologies to facilitate and improve practical applications of phytoremediation of metal-polluted soils.
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lead zinc and iron fe2 tolerances in Wetland Plants and relation to root anatomy and spatial pattern of rol
Environmental and Experimental Botany, 2009Co-Authors: H Deng, Zhihong Ye, Ming Hung WongAbstract:Abstract Metal (Pb, Zn and Fe 2+ ) tolerances, root anatomy and profile of radial oxygen loss (ROL) along the root (i.e., spatial pattern of ROL) were studied in 10 emergent Wetland Plants. The species studied could be classified into three groups. Group I included Alternanthera philoxeroides , Beckmannia syzigachne , Oenanthe javanica and Polypogon fugax , with high ROL along the whole length of root (‘partial barrier’ to ROL). Group II included Cyperus flabelliformis , Cyperus malaccensis , Juncus effusus , Leersia hexandra and Panicum paludosum , ROL of which was remarkably high just behind the root apex, but decreased significantly at relatively basal regions (‘tight barrier’ to ROL). Group III consisted of only Neyraudia reynaudiana , with extremely low ROL along the length of root. The results indicated that metal tolerance in Wetland Plants was related to root anatomy and spatial pattern of ROL. Co-evolution of metal (Fe and Zn) tolerance and flood tolerance possibly developed in Wetland Plants since species showing a ‘tight barrier’ to ROL (a common trait of flood-tolerant species) in basal root zones had higher Fe and Zn tolerances than those showing a ‘partial barrier’. Root anatomy such as lignin and suberin deposition contributed to a ‘tight barrier’ in root and conferred to exclusion ability in tolerant species.
Norman Terry - One of the best experts on this subject based on the ideXlab platform.
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phytoaccumulation of trace elements by Wetland Plants iii uptake and accumulation of ten trace elements by twelve plant species
Journal of Environmental Quality, 1999Co-Authors: Jinhong Qian, Adel Zayed, Mei Yu, Norman TerryAbstract:Interest is increasing in using Wetland Plants in constructed Wetlands to remove toxic elements from polluted wastewater. To identify those Wetland Plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual Plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038),more » Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.« less
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rhizosphere bacteria enhance the accumulation of selenium and mercury in Wetland Plants
Planta, 1999Co-Authors: M P De Souza, C P A Huang, N Chee, Norman TerryAbstract:The role of rhizosphere bacteria in facilitating Se and Hg accumulation in two Wetland Plants, saltmarsh bulrush (Scirpus robustus Pursh) and rabbitfoot grass (Polypogon monspeliensis (L.) Desf.), was studied. Ampicillin-amended Plants (i.e., with inhibited rhizosphere bacteria) supplied with Na2SeO4 or HgCl2 had significantly lower concentrations of Se and Hg, respectively, in roots than Plants without ampicillin. These results were confirmed by inoculating axenic saltmarsh bulrush Plants with bacteria isolated from the rhizosphere of Plants collected from the field; these Plants accumulated significantly more Se and Hg compared to axenic controls. Therefore, rhizosphere bacteria can increase the efficiency of Se and Hg phytoremediation by promoting the accumulation of Se and Hg in tissues of Wetland Plants.
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phytoaccumulation of trace elements by Wetland Plants ii water hyacinth
Journal of Environmental Quality, 1999Co-Authors: Adel Zayed, M P De Souza, Jinhong Qian, Norman TerryAbstract:Wetland Plants are being used successfully for the phytoremediation of trace elements in natural and constructed Wetlands. This study demonstrates the potential of water hyacinth (Eichhornia crassipes), an aquatic floating plant, for the phytoremediation of six trace elements. The ability of water hyacinth to take up and translocate six trace elements-As(V), Cd(II), Cr(VI), Cu(II), Ni(II), and Se(VI)-was studied under controlled conditions. Water hyacinth accumulated Cd and Cr best, Se and Cu at moderate levels, and was a poor accumulator of As and Ni. The highest levels of Cd found in shoots and roots were 371 and 6103 mg kg -1 dry wt., respectively, and those of Cr were 119 and 3951 mg kg ' dry wt., respectively. Cadmium, Cr, Cu, Ni, and As were more highly accumulated in roots than in shoots. In contrast, Se was accumulated more in shoots than in roots at most external concentrations. Water hyacinth had high trace element bio-concentration factors when supplied with low external concentrations of all six elements, particularly Cd (highest BCF = 2150), Cr (1823), and Cu (595). Therefore, water hyacinth will be very efficient at phytoextracting trace elements from wastewater containing low concentrations of these elements. We conclude that water hyacinth is a promising candidate for phytoremediation of wastewater polluted with Cd, Cr, Cu, and Se.
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phytoaccumulation of trace elements by Wetland Plants i duckweed
Journal of Environmental Quality, 1998Co-Authors: Adel Zayed, Suvarnalatha Gowthaman, Norman TerryAbstract:There has been much interest recently in the use of constructed Wetlands for the removal of toxic trace elements from wastewaters. Wetland Plants play an important role in the trace elements removal process. It is not known, however, which Wetland plant species absorb specific trace elements at the fastest rates. Such knowledge is essential to maximize the efficiency of trace element removal by Wetlands. In this study, we investigated the potential of duckweed (Lemna minor L.) to accumulate Cd, Cr, Cu, Ni, Pb, and Se when supplied individually in a nutrient solution at a series of concentrations ranged from 0.1 to 10 mg L -1 . The results show that under experimental conditions, duckweed proved to be a good accumulator of Cd, Se, and Cu, a moderate accumulator of Cr, and a poor accumulator of Ni and Pb. The highest concentrations of each trace element accumulated in duckweed tissues were 133 g Cd kg -1 , 4.27 g Se kg -1 , 336 g Cu kg -1 , 2.87 g Cr kg -1 , 1.79 g Ni kg -1 , and 0.63 g Pb kg -1 . Duckweed exhibited some symptoms of toxicity (e.g, reduced growth, chlorosis) at higher levels of element supply (except for Cr). The toxicity effect of each trace element on plant growth was, in descending order of damage, Cu > Se > Pb > Cd > Ni > Cr. We conclude that duckweed shows promise for the removal of Cd, Se, and Cu from contaminated wastewater since it accumulates high concentrations of these elements. Further, the growth rates and harvest potential make duckweed a good species for phytoremediation activities.
Ole Pedersen - One of the best experts on this subject based on the ideXlab platform.
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a perspective on underwater photosynthesis in submerged terrestrial Wetland Plants
Aob Plants, 2011Co-Authors: Timothy D Colmer, Anders Winkel, Ole PedersenAbstract:Background and aims Wetland Plants inhabit flood-prone areas and therefore can experience episodes of complete submergence. Submergence impedes exchange of O2 and CO2 between leaves and the environment, and light availability is also reduced. The present review examines limitations to underwater net photosynthesis (PN) by terrestrial (i.e. usually emergent) Wetland Plants, as compared with submerged aquatic Plants, with focus on leaf traits for enhanced CO2 acquisition.
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underwater photosynthesis and respiration in leaves of submerged Wetland Plants gas films improve co2 and o2 exchange
New Phytologist, 2008Co-Authors: Timothy D Colmer, Ole PedersenAbstract:Summary • Many Wetland Plants have gas films on submerged leaf surfaces. We tested the hypotheses that leaf gas films enhance CO2 uptake for net photosynthesis (PN) during light periods, and enhance O2 uptake for respiration during dark periods. • Leaves of four Wetland species that form gas films, and two species that do not, were used. Gas films were also experimentally removed by brushing with 0.05% (v/v) Triton X. Net O2 production in light, or O2 consumption in darkness, was measured at various CO2 and O2 concentrations. • When gas films were removed, O2 uptake in darkness was already diffusion-limited at 20.6 kPa (critical O2 pressure for respiration, COPR≥ 284 mmol O2 m−3), whereas for some leaves with gas films, O2 uptake declined only at approx. 4 kPa (COPR 54 mmol O2 m−3). Gas films also improved CO2 uptake so that, during light periods, underwater PN was enhanced up to sixfold. • Gas films on submerged leaves enable continued gas exchange via stomata and thus bypassing of cuticle resistance, enhancing exchange of O2 and CO2 with the surrounding water, and therefore underwater PN and respiration.
Junxing Yang - One of the best experts on this subject based on the ideXlab platform.
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antioxidant enzymes and proteins of Wetland Plants their relation to pb tolerance and accumulation
Environmental Science and Pollution Research, 2015Co-Authors: Junxing Yang, Zhihong YeAbstract:Constructed Wetlands used to clean up toxic metals such as lead (Pb) from contaminated wastewater are considered as an effective and low-cost technology. The effect of Pb on the biomass, tolerance, soluble protein, and antioxidant enzymes in 18 candidate Wetland plant species grown in soils without (control) and spiked with 900 and 1800 mg Pb kg(-1) was studied in a pot trial. Our pot experiment showed that the biomass, tolerance, and leaf protein contents decreased with increasing concentrations of Pb in soil. There were significant differences between the Plants in their Pb tolerance indices (29-82 % in the 900 mg Pb kg(-1) amended soil) and also Pb uptake (13-749 mg kg(-1) in shoots and 1112-4891 mg kg(-1) in roots, in the same treatments). Activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of most of the Plants increased with increasing level of soil Pb concentration. Conversely, catalase (CAT) activity in leaves declined when Plants were subjected to Pb stress. Lead accumulation by the 18 Wetland plant species screened was strongly dependent on the species and Pb concentrations in the soil. However, Pb translocation from root to shoot was generally low in all species. Increases in SOD and POD activities suggest that the antioxidant system may play an important role in alleviating Pb toxicity in Wetland Plants. The data obtained should help in future species selection for the use in designing Wetlands in Pb-contaminated environments.
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root porosity radial oxygen loss and iron plaque on roots of Wetland Plants in relation to zinc tolerance and accumulation
Plant and Soil, 2014Co-Authors: Junxing Yang, Zhihong YeAbstract:Background and aims Wetland Plants have been widely used in constructed Wetlands for the clean-up of metal-contaminated waters. This study investigated the relationship between rate of radial oxygen loss (ROL), root porosity, Zn uptake and tolerance, Fe plaque formation in Wetland Plants.
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root induced changes of ph eh fe ii and fractions of pb and zn in rhizosphere soils of four Wetland Plants with different radial oxygen losses
Pedosphere, 2012Co-Authors: Junxing Yang, Y E ZhihongAbstract:A rhizobox experiment was conducted to compare iron (Fe) oxidation and changes of pH, redox potential (Eh) and fractions of zinc (Zn) and lead (Pb) in rhizosphere and non-rhizosphere soils of four emergent-rooted Wetland Plants (Echinodorus macrophyllus, Eleocharis geniculata, Hydrocotyle vulgaris and Veronica serpyllifolia) with different radial oxygen loss (ROL) from roots. The results indicated that all these Wetland Plants decreased pH and concentration of Fe(II) but increased the Eh in the rhizosphere soils. Pb and Zn were transformed from unstable fractions to more stable fractions in the rhizosphere soils, so decreasing their potential metal mobility factors (MF). Among the four Plants, E. macrophyllus, with the highest ROL and root biomass, possessed the greatest ability in formation of Fe plaque and in the reduction of heavy metal MFs in the rhizosphere soil. Wetland Plants, with higher ROLs and root biomass, may thus be effective in decreasing potential long-term heavy metal bioavailabilities.
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Metal accumulation and tolerance in Wetland Plants
Frontiers of Biology in China, 2009Co-Authors: Junxing Yang, Zhihong YeAbstract:This paper briefly reviews the progress in studies of Wetland Plants in terms of heavy metal pollution. The current research mainly includes the following areas: (1) metal uptake, translocation, and distributions in Wetland Plants and toxicological effects on Wetland Plants, (2) radial oxygen loss (ROL) of Wetland Plants and its effects on metal mobility in rhizosphere soils, (3) constitutional metal tolerance in Wetland Plants, and (4) mechanisms of metal tolerance by Wetland Plants. Although a number of accomplishments have been achieved, many issues still remain unanswered. The future research effort is likely to focus on the ROL of Wetland Plants affecting metal speciation and bioavailability in rhizosphere soils, and the development of rhizosphere management technologies to facilitate and improve practical applications of phytoremediation of metal-polluted soils.
Zhang He Chen - One of the best experts on this subject based on the ideXlab platform.
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radial oxygen loss photosynthesis and nutrient removal of 35 Wetland Plants
Ecological Engineering, 2012Co-Authors: Yang Zhang, Zhang He ChenAbstract:Abstract The aim of the present study was to test the correlation between radial oxygen loss (ROL), photosynthesis, and nutrient removal based on the hypothesis that ROL was principally a positive physiological process of Wetland Plants, and was correlated with photosynthesis and nutrient removal. Thirty five emergent Wetland Plants were used for the measurement of ROL, photosynthesis, and nutrient removal in micro-scale Wetlands in a climate chamber. Significant differences among thirty five species were tested in ROL, photosynthetic rate, and nutrient removal rates. ROL was positively correlated with photosynthetic rate ( P = 0.000), transpiration rate ( P = 0.005), root activity ( P = 0.000), root biomass of D ≤ 1 mm ( P = 0.002), above-ground biomass ( P = 0.030), leaf biomass ( P = 0.023), root porosity ( P = 0.000), maximum root length ( P = 0.011), and removal rates of TN and TP ( P = 0.000, 0.002), while negatively related to root biomass of D ≥ 3 mm, and root longevity ( P = 0.022, 0.007). All the indices which were positively correlated with ROL, also positively correlated with plant growth. The results suggest that ROL may be an active physiological process or at least involves physiological processes of Wetland Plants. Significant differences existed among different Wetland Plants in ROL, photosynthesis, and nutrient removal, which should be considered in plant selection for constructed Wetlands.
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root features related to plant growth and nutrient removal of 35 Wetland Plants
Water Research, 2011Co-Authors: Shu Qiang Wang, Chang Lian Peng, Zhang He ChenAbstract:Abstract Morphological, structural, and eco-physiological features of roots, nutrient removal, and correlation between the indices were comparatively studied for 35 emergent Wetland Plants in small-scale Wetlands for further investigation into the hypothesis of two types of Wetland plant roots ( Chen et al., 2004 ). Significant differences in root morphological, structural, and eco-physiological features were found among the 35 species. They were divided into two types: fibrous-root Plants and thick-root Plants. The fibrous-root Plants had most or all roots of diameter ( D ) ≤ 1 mm. Roots of D > 1 mm also had many fine and long lateral roots of D ≤ 1 mm. The roots of these Plants were long and had a thin epidermis and a low degree of lignification. The roots of the thick-root Plants were almost all thicker than 1 mm, and generally had no further fine lateral roots. The roots were short, smooth, and fleshy, and had a thick epidermis. Root porosity of the fibrous-root Plants was higher than that of the thick-root Plants ( p = 0.001). The aerenchyma of the fibrous-root Plants was composed of large cavities which were formed from many small cavities, and distributed radially between the exodermis and vascular tissues. The aerenchyma of the thick-root Plants had a large number of small cavities which were distributed in the mediopellis. The fibrous-root Plants had a significantly larger root biomass of D ≤ 1 mm, of 1 mm D p = 0.003, 0.018, 0.020, 0.032, 0.042, 0.001). The fibrous-root Plants also had significantly higher radial oxygen loss (ROL), root activity, photosynthetic rate, transpiration rate, and removal rates of total nitrogen and total phosphorus than the thick-root Plants ( p = 0.001, 0.008, 0.010, 0.004, 0.020, 0.002). The results indicate that significantly different root morphological and structural features existed among different Wetland Plants, and these features had a close relationship to nutrient removal capacity.
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Root features related to plant growth and nutrient removal of 35 Wetland Plants
Water Research, 2011Co-Authors: Wen Ling Lai, Shu Qiang Wang, Chang Lian Peng, Zhang He ChenAbstract:Morphological, structural, and eco-physiological features of roots, nutrient removal, and correlation between the indices were comparatively studied for 35 emergent Wetland Plants in small-scale Wetlands for further investigation into the hypothesis of two types of Wetland plant roots (Chen et al., 2004). Significant differences in root morphological, structural, and eco-physiological features were found among the 35 species. They were divided into two types: fibrous-root Plants and thick-root Plants. The fibrous-root Plants had most or all roots of diameter (D) ≤ 1 mm. Roots of D > 1 mm also had many fine and long lateral roots of D ≤ 1 mm. The roots of these Plants were long and had a thin epidermis and a low degree of lignification. The roots of the thick-root Plants were almost all thicker than 1 mm, and generally had no further fine lateral roots. The roots were short, smooth, and fleshy, and had a thick epidermis. Root porosity of the fibrous-root Plants was higher than that of the thick-root Plants (p = 0.001). The aerenchyma of the fibrous-root Plants was composed of large cavities which were formed from many small cavities, and distributed radially between the exodermis and vascular tissues. The aerenchyma of the thick-root Plants had a large number of small cavities which were distributed in the mediopellis. The fibrous-root Plants had a significantly larger root biomass of D ≤ 1 mm, of 1 mm < D < 3 mm, above-ground biomass, total biomass, and longer root system, but shorter root longevity than those of the thick-root Plants (p = 0.003, 0.018, 0.020, 0.032, 0.042, 0.001). The fibrous-root Plants also had significantly higher radial oxygen loss (ROL), root activity, photosynthetic rate, transpiration rate, and removal rates of total nitrogen and total phosphorus than the thick-root Plants (p = 0.001, 0.008, 0.010, 0.004, 0.020, 0.002). The results indicate that significantly different root morphological and structural features existed among different Wetland Plants, and these features had a close relationship to nutrient removal capacity. © 2011 Elsevier Ltd.
