We aim to investigate the effects of humic acid （HA） and citric acid （CA） on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. ...We aim to investigate the effects of humic acid （HA） and citric acid （CA） on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. The EC50 values of Cd increased from 3.36 μmol/L to 4.96 and 7.33 μmol/L at 50 and 250 mg/L HA, respectively, but decreased to 1.39 μmol/L in the presence of CA based on free ion activity model （FIAM）. HA decreased the relative subcellular distribution of Cd in the heat-denatured proteins （decreased from 54% to 33%） but increased Cd in the heat-stable proteins in root （from 25% to 50%） at 7.61 μmol/L {Cd2＋} （free Cd activity）, which resulted in decreasing Cd toxicity. However, CA increased Cd toxicity due to the increased internalization of Cd although the relative subcellular distributions of Cd exhibited a decrease in the heat-denatured proteins and increase in the granule fraction compared to the control at high-level Cd. The FIAM could not predict the toxicity of Cd in the presence of organic acids. Alternatively, the internal Cd accumulation and subcellular Cd concentration were better to describe the toxicity of Cd to wheat.展开更多
In China, great efforts are being made to remediate farmlands polluted by heavy metals. In this study, a soil pot experiment was conducted to examine the effects of a new-type cleaning agent, methylglycinediacetic aci...In China, great efforts are being made to remediate farmlands polluted by heavy metals. In this study, a soil pot experiment was conducted to examine the effects of a new-type cleaning agent, methylglycinediacetic acid(MGDA), and a plant growth regulator(PGR), diethl aminoethyl hexanoate(DA-6), on plant growth and extraction and detoxification of cadmium(Cd) by ryegrass. The results showed that foliar spray of DA-6 alone improved plant growth, with root length and shoot dry biomass increased by 38.5%–58.6% and 71.1%–89.3%, respectively, whereas addition of MGDA alone decreased root length and shoot dry biomass by 10.3%–18.6%and 9.1%–21.8%, respectively. Diethl aminoethyl hexanoate promoted the binding of Cd to cell walls and thus alleviated the toxicity of Cd and/or MGDA to plants. Applications of DA-6 and/or MGDA resulted in a significant increase in Cd extraction efficiency(P < 0.05), and the efficiency decreased in the order of MGDA + DA-6 > DA-6 > MGDA. The treatment of MGDA + DA-6 achieved 2.2%, 1.7%, and 0.8% Cd extraction efficiency by ryegrass in soils spiked with 25, 50, 100 mg Cd kg^(-1), respectively. Therefore,treatment of MGDA + DA-6 could be an efficient method for enhancing phytoremediation of Cd-contaminated soil by ryegrass.展开更多
Metal pollution has been a major environmental problem in China with the increasing industrialization.The prediction of metal toxicity is extremely challenging due to the complex metal handling and sequestration strat...Metal pollution has been a major environmental problem in China with the increasing industrialization.The prediction of metal toxicity is extremely challenging due to the complex metal handling and sequestration strategies of different aquatic organisms.In this review,the recent progress made in this area is discussed.In particular,the subcellular partitioning model which has gained recognition in recent years is highlighted.The subcellular partitioning model appears to be dependable for predicting the toxicity in unicellular phytoplankton.It is important to understand the differential ways that metals bind to different subcellular pools and their ecotoxicological significance in aquatic organisms under different exposure regimes.It is also critical to appreciate that every metal is unique to each aquatic species.Despite the huge progress made over the past 30 years,much remains to be done to fully understand metal toxicity in aquatic organisms.展开更多
Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated so...Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations(0, 25, 50, 100, 200 and 400 mg/L) in culture solution at14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots.Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems,respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaC l-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.展开更多
基金supported by the National Natural Science Foundation of China (No. 21077111, 41125007)
文摘We aim to investigate the effects of humic acid （HA） and citric acid （CA） on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. The EC50 values of Cd increased from 3.36 μmol/L to 4.96 and 7.33 μmol/L at 50 and 250 mg/L HA, respectively, but decreased to 1.39 μmol/L in the presence of CA based on free ion activity model （FIAM）. HA decreased the relative subcellular distribution of Cd in the heat-denatured proteins （decreased from 54% to 33%） but increased Cd in the heat-stable proteins in root （from 25% to 50%） at 7.61 μmol/L {Cd2＋} （free Cd activity）, which resulted in decreasing Cd toxicity. However, CA increased Cd toxicity due to the increased internalization of Cd although the relative subcellular distributions of Cd exhibited a decrease in the heat-denatured proteins and increase in the granule fraction compared to the control at high-level Cd. The FIAM could not predict the toxicity of Cd in the presence of organic acids. Alternatively, the internal Cd accumulation and subcellular Cd concentration were better to describe the toxicity of Cd to wheat.
基金supported by the National Natural Science Foundation of China (Nos. 41501521 and 41301327)
文摘In China, great efforts are being made to remediate farmlands polluted by heavy metals. In this study, a soil pot experiment was conducted to examine the effects of a new-type cleaning agent, methylglycinediacetic acid(MGDA), and a plant growth regulator(PGR), diethl aminoethyl hexanoate(DA-6), on plant growth and extraction and detoxification of cadmium(Cd) by ryegrass. The results showed that foliar spray of DA-6 alone improved plant growth, with root length and shoot dry biomass increased by 38.5%–58.6% and 71.1%–89.3%, respectively, whereas addition of MGDA alone decreased root length and shoot dry biomass by 10.3%–18.6%and 9.1%–21.8%, respectively. Diethl aminoethyl hexanoate promoted the binding of Cd to cell walls and thus alleviated the toxicity of Cd and/or MGDA to plants. Applications of DA-6 and/or MGDA resulted in a significant increase in Cd extraction efficiency(P < 0.05), and the efficiency decreased in the order of MGDA + DA-6 > DA-6 > MGDA. The treatment of MGDA + DA-6 achieved 2.2%, 1.7%, and 0.8% Cd extraction efficiency by ryegrass in soils spiked with 25, 50, 100 mg Cd kg^(-1), respectively. Therefore,treatment of MGDA + DA-6 could be an efficient method for enhancing phytoremediation of Cd-contaminated soil by ryegrass.
基金supported by the Research Grants Council of Hong Kong(662610 and 663009)the Program for Changjiang Scholars and Innovative Research Team in University(IRT0941)
文摘Metal pollution has been a major environmental problem in China with the increasing industrialization.The prediction of metal toxicity is extremely challenging due to the complex metal handling and sequestration strategies of different aquatic organisms.In this review,the recent progress made in this area is discussed.In particular,the subcellular partitioning model which has gained recognition in recent years is highlighted.The subcellular partitioning model appears to be dependable for predicting the toxicity in unicellular phytoplankton.It is important to understand the differential ways that metals bind to different subcellular pools and their ecotoxicological significance in aquatic organisms under different exposure regimes.It is also critical to appreciate that every metal is unique to each aquatic species.Despite the huge progress made over the past 30 years,much remains to be done to fully understand metal toxicity in aquatic organisms.
基金supported by the National Natural Science Funds of China (No. 31300509)the special funds from the Central Scientific Research Institute of Public Welfare (No.CAFYBB2014QB016)the Natural Science Funds of Beijing (No. 8152032)
文摘Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations(0, 25, 50, 100, 200 and 400 mg/L) in culture solution at14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots.Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems,respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaC l-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.
