Publications by authors named "Qu-Sheng Li"

22 Publications

  • Page 1 of 1

Biomineralization of Cd and inhibition on rhizobacterial Cd mobilization function by Bacillus Cereus to improve safety of maize grains.

Chemosphere 2021 Jun 10;283:131095. Epub 2021 Jun 10.

Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China. Electronic address:

Reducing cadmium (Cd) bioavailability and rhizobacterial Cd mobilization functions in the rhizosphere via the inoculation of screened microbial inoculum is an environmental-friendly strategy to improve safety of crop grains. In this study, Bacillus Cereus, a model Cd resistant strain, was selected to explore its effects on Cd bioavailability and uptake, bacterial metabolic functions related to Cd mobilization. Results indicated that inoculation of Bacillus Cereus in maize roots of sand pot with water-soluble Cd (0.06-0.15 mg/kg) and soil pot with high Cd-contaminated soil (total Cd: 2.33 mg/kg; Cd extracted by NHNO: 38.6 μg/kg) could decrease water-soluble Cd ion concentration by 7.7-30.1% and Cd extracted with NHNO solution by 7.8-22.5%, inducing Cd concentrations in maize grains reduced by 10.6-39.9% and 17.4-38.6%, respectively. Even for a single inoculation in soil, Cd concentration in maize grains still satisfy food safety requirements (Cd content: 0.1 mg/kg dry weight) due to its successful colonization on root surface of maize. Bacillus Cereus could enrich more plant growth promotion bacteria (PGPB) and down-regulate the expression of genes related to bacterial motility, membrane transports, carbon and nitrogen metabolism in the rhizosphere soil, decreasing Cd bioavailability in soil. Approximately 80% Cd in media was transferred into intracellular, meanwhile Cd salts (sulfide and/or phosphate) were produced in Bacillus Cereus through biomineralization process. Overall, this study could provide a feasible method for improving safety of maize grains via the inoculation of Bacillus Cereus under Cd pollution.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131095DOI Listing
June 2021

Nitrogen fertilizer affects rhizosphere Cd re-mobilization by mediating gene AmALM2 and AmALMT7 expression in edible amaranth roots.

J Hazard Mater 2021 Jun 6;418:126310. Epub 2021 Jun 6.

Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China. Electronic address:

In-situ stabilization of Cd-contaminated farmland is a commonly used remediation technology. Yet, rhizosphere metabolites (e.g., organic acids) during crop cultivation may cause Cd re-mobilization and over-accumulation. Here, we identified four pivotal cytomembrane-localized genes underlying Cd accumulation difference between two contrasting edible amaranth cultivars based on root gene expression profile, studied their subcellular localization and functional characteristics, and then investigated effects of nitrogen fertilizer on their expression and rhizosphere Cd re-mobilization. Results showed that more Cd accumulated by edible amaranth was due to rhizosphere Cd mobilization by mediating high expression of AmALMT2 and AmALMT7 genes, not Cd transporters in roots. This was confirmed by heterologous expression of AmALMT2 and AmALMT7 genes in Arabidopsis thaliana, since they mediated malic, fumaric, succinic, and aspartic acids efflux. Furthermore, nitrogen influencing rhizosphere acidification might be closely associated with organic acids efflux genes. Compared with N-NO application, N-NH was massively assimilated into glutamates and oxaloacetates through up-regulating glutamine synthetase and alanine-aspartate-glutamate metabolic pathways, thereby enhancing TCA cycle and organic acids efflux dominated by binary carboxylic acids via up-regulating AmALMT2 and AmALMT7 genes, which finally caused Cd re-mobilization. Therefore, N-NO-dominated nitrogen retarded rhizosphere Cd re-mobilization via inhibiting organic acids efflux function of AmALMT2 and AmALMT7 proteins.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126310DOI Listing
June 2021

Integration of CW-MFC and anaerobic granular sludge to explore the intensified ammonification-nitrification-denitrification processes for nitrogen removal.

Chemosphere 2021 Sep 1;278:130428. Epub 2021 Apr 1.

State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China. Electronic address:

The integration of constructed wetland-microbial fuel cell (CW-MFC) and anaerobic granular sludge (AGS) is an important way to promote its ammonification efficiency and decrease the land use scale. This study explored the integration of CW-MFC and AGS for nitrogen removal via the intensified ammonification-nitrification-denitrification processes with initial NH-N, NO-N, Org-N and total nitrogen (TN) concentrations of 10.5, 13.8, 21.4, and 45.7 mg L in wastewater. Two reactors with AGS inoculated with a separated area (R1) and directly inoculated into gravel substrate (R2) were designed, respectively. Results showed that chemical oxygen demand (COD) removal efficiency could reach 85% in R1 and 81% in R2, and the conversion of Org-N to NH-N and NO-N to gaseous nitrogen were 80% and 90%, respectively. Although the conversion efficiency of NH-N to NO-N/NO-N via nitrification process was only 18%, it could reach 45%, 94%, and 98% with the aeration rates of 50-, 100-, and 200-mL min. According to microstructural property and microbial community analyses, the separation gravel substrate and AGS areas in R1 availed for stable particle size of AGS, archaeal diversity, and metabolic activity even with a 1.5 times daily wastewater treatment capacity than that of R2. Overall, although the intensified ammonification-nitrification-denitrification processes for nitrogen removal could be achieved with supplementary aeration, further investigation is still needed to explore other substrate materials and high CW-MFC/AGS volume ratio for intensified nitrification process in CW-MFC associated with AGS.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130428DOI Listing
September 2021

Nitrogen fertilizer management affects remobilization of the immobilized cadmium in soil and its accumulation in crop tissues.

Environ Sci Pollut Res Int 2021 Jun 20;28(24):31640-31652. Epub 2021 Feb 20.

College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China.

Immobilization of soil cadmium (Cd) has been the strategy mostly used in remediation of Cd-contaminated arable soil. However, Cd might be remobilized after the immobilization process through the acid-soluble and complexation effects. Development of agronomic management technologies to prevent soil Cd remobilization after the immobilization process was an important pathway to control the food safety of agricultural products in soils with the immobilized Cd. In this study, the ammonia (NH-N) and nitrate (NO-N) forms with concentrations of 60, 90, and 150 mg-N kg soil were performed for evaluating their effects on Cd remobilization with planted or unplanted treatments and Cd accumulation in tissues of edible amaranth (Liuye). With an initial soil palygorskite-bound fraction Cd concentration of 0.6 mg kg, bioavailable Cd in rhizosphere soils and Cd in crop shoots respectively increased from 11.4 to 20.6 μg kg (dry soil weight) and 6.92 to 14.92 mg kg (dry plant weight) in planted NH-N treatments, while significantly lower concentrations of bioavailable Cd in rhizosphere soils and Cd in crop tissues were observed with planted NO-N treatments. Compared with that of planted NO-N treatments, decreasing pH value (i.e., 7.64 to 7.18) induced by root proton efflux during the absorption of NH-N, enhancive organic/amino acid (oxalic acid, lactic acid, L-proline, and so on) secretion from roots, and increasing abundance of bacteria distributed in phyla Proteobacteria, Cyanobacteria, and Bacteroidetes with Cd mobilization ability in rhizosphere soils were the main reasons found in this study for the higher Cd remobilization in soils and Cd accumulation in crop under NH-N treatments. Moreover, the direct effect of NH-N on remobilization of immobilized Cd by upregulating the expression abundances of genes associated with pyruvate metabolism and amino acids metabolism was more significant than that of NO-N. In summary, the use of NO-N as preferred N fertilizer was more efficient to ensure the food safety of agricultural products than that of NH-N in Cd-contaminated arable soil after immobilization process.
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http://dx.doi.org/10.1007/s11356-021-12868-zDOI Listing
June 2021

Biological mechanisms of cadmium accumulation in edible Amaranth (Amaranthus mangostanus L.) cultivars promoted by salinity: A transcriptome analysis.

Environ Pollut 2020 Jul 4;262:114304. Epub 2020 Mar 4.

Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China; Research Center of Low Carbon Economy for Guangzhou Region, Jinan University, Guangzhou, 510632, China.

Strategies to prevent cadmium (Cd) mobilization by crops under salinity conditions differs among distinct genotypes, but the biological mechanisms of Cd accumulation in different genotype crops promoted by salinity have remained scarce. In this study, we investigated the biological mechanisms of Cd accumulation in two quite different amaranth cultivars of low-Cd accumulator Quanhong (QH) and high-Cd accumulator Liuye (LY) in response to salt stress. Transcriptomes analysis was carried out on leaves and roots tissues of LY and QH grown with exchangeable Cd 0.27 mg kg and salinity 3.0 g kg treatment or control conditions, respectively. A total of 3224 differentially expressed genes (DEGs) in LY (1119 in roots, 2105 in leaves) and 848 in QH (207 in roots, 641 in leaves) were identified. Almost in each fold change category (2-2, 2-2, >2), the numbers of DEGs induced by salinity in LY treatments were much more than those in QH treatments, indicating that LY is more salt sensitive. Gene ontology (GO) analysis revealed that salinity stress promoted soil acidification and Cd mobilization in LY treatments through the enhancive expression of genes related to adenine metabolism (84-fold enrichment) and proton pumping ATPase (50-fold enrichment) in roots, and carbohydrate hydrolysis (2.5-fold enrichment) in leaves compared with that of whole genome, respectively. The genes expression of organic acid transporter (ALMT) was promoted by 2.71- to 3.94-fold in roots, facilitating the secretion of organic acids. Salt stress also inhibited the expression of key enzymes related to cell wall biosynthesis in roots, reducing the physical barriers for Cd uptake. All these processes altered in LY were more substantially compared with that of QH, suggesting that salt sensitive cultivars might accumulate more Cd and pose a higher health risk.
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http://dx.doi.org/10.1016/j.envpol.2020.114304DOI Listing
July 2020

Improving cadmium mobilization by phosphate-solubilizing bacteria via regulating organic acids metabolism with potassium.

Chemosphere 2020 Apr 25;244:125475. Epub 2019 Nov 25.

Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China. Electronic address:

Organic acids secreted by phosphorus-solubilizing bacteria (PSB) is one of the main biological metabolites with cadmium (Cd) mobilization capacity in the conversion of insoluble precipitate forms to bioavailable forms in contaminated soil. However, the fluctuating concentrations of nutrient elements caused by agricultural activities may result in the substantial variances of carbohydrate metabolism of microorganisms involved in Cd remediation, it is therefore essential to study how metabolic strategies, especially for organic acids, affected by the environmentally friendly fertilizers, such as potassium (K). In this study, adding K (KCl) concentrations from 0.0 to 100.0 mg/L in medium clearly accelerated Cd mobilization from 15.9 to 35.9 mg/L via inducing the secretion of tartaric acid, 3-hydroxybutyrate, fumaric and succinic acids, increased by 10.0-, 7.5-, 4.3- and 4.1-fold changes, respectively. Current data revealed that the significant differences of metabolic pathways and genes expressions with the varied K concentrations included: ⅰ) K induces a substantial up-regulation in metabolic pathway of pyruvic acid to oxaloacetate and tartaric acids; ⅱ) the varied expression of genes involved in encoding enzymes of tricarboxylic acid cycle result in the up-regulated fumaric acid, succinic acid and 3-hydroxybutyrate; ⅲ) the expression of genes related enzyme cysteine and glutamate metabolism processes promoted with the increasing bioavailable Cd concentrations. Besides, P-type ATPase activity increased with K levels, indicating that H efflux and medium acidification were strengthened. In general, an appropriate enhancement of K based fertilizer is an effective manner for soil Cd remediation via the regulation of organic acids metabolism and H secretion of PSB.
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http://dx.doi.org/10.1016/j.chemosphere.2019.125475DOI Listing
April 2020

Phosphate-solubilizing bacteria will not significantly remobilize soil cadmium remediated by weathered coal.

Environ Sci Pollut Res Int 2019 Oct 6;26(28):29003-29011. Epub 2019 Aug 6.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou, 510632, China.

Cadmium (Cd) re-mobilize by phosphate-solubilizing bacteria (PSB) from immobilization contaminated soil has drawn great attention due to its serious threat to human health through food chain. However, Cd binding with weathered coal (WC), an effective Cd immobilization material, will be re-mobilized by PSB or not is still unclear. In this study, the soil and sand pots with Cd were respectively mixed with the weight fractions of 0‰, 2‰, and 3‰ WC, inoculated with or without PSB, and planted with Amaranthus mangostanus L. The experimental results indicated that: (i) Cd in soil was transformed into organic fraction with WC, which has been led to the Cd accumulation concentrations in roots and shoots reduced by 38.8% and 20.5%, respectively; (ii) PSB could promote the concentration of exchangeable-Cd fraction and soil Cd uptake by amaranth in all treatments; and (iii) WC application in sand pot respectively reduced the Cd accumulation by 47.5% in roots and 24.1% in shoots, but PSB inoculation showed no significant effect on Cd accumulation in plants under WC application. SEM, zeta potential, and FT-IR results showed that PSB inoculation after Cd immobilized by WC had no influence on the microstructure, amount of negative charge, type, and content of functional groups in WC, indicating that organic fraction Cd in WC was not re-mobilized by PSB. Therefore, the application of WC in contaminated soil was conducive to transforming Cd in organic-bound forms and intensifying Cd immobilization effects.
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http://dx.doi.org/10.1007/s11356-019-06142-6DOI Listing
October 2019

Interactive effects between cadmium stabilized by palygorskite and mobilized by siderophores from Pseudomonas fluorescens.

Ecotoxicol Environ Saf 2019 Oct 12;181:265-273. Epub 2019 Jun 12.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou, 510632, China. Electronic address:

The application of palygorskite (PAL) for potentially toxic trace elements (Cd, Ni, etc.) remediation in polluted soil can substantially reduce the bioavailability and toxicity of these hazard materials. However, the secretion of organic acids and siderophores by microorganisms might result in the re-mobilization of cadmium (Cd) in PAL-bound forms (PAL-Cd). In this study, the interactive effects between Cd stabilized by PAL and mobilized by siderophores from Pseudomonas fluorescens were performed with four flask-shaking experimental treatments, namely, strain with or without an ability of siderophores production respectively associated with or without PAL-Cd. The GC-MS and UHPLC-MS test methods were used to analyze the concentrations of metabolites. Results showed that the Cd mobilized by strain with siderophores production was 22.1% higher than that of strain without the ability of siderophores production (p < 0.05). The mobilization of Cd in PAL in turn significantly reduced the siderophores production of Pseudomonas fluorescens by 25.1% (p < 0.05). The numbers of metabolites significantly up-regulated and down-regulated were 9 and 22 in strain groups with PAL-Cd addition compared with the groups without PAL-Cd, respectively. Metabolomics analysis revealed that the mobilized Cd affects the signal transduction pathway and primary metabolic processes, reduces the metabolic capacity of pentose phosphate pathway, glycolysis and tricarboxylic acid cycle pathway. These changes inhibit the ability of strain to biosynthesize amino acids during the mobilization processes, further reducing the capacity of Pseudomonas fluorescens to produce siderophores. This study provides a useful information on how to select soil Cd-stabilizing materials in a targeted manner and how to avoid Cd re-mobilization by siderophores.
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http://dx.doi.org/10.1016/j.ecoenv.2019.06.012DOI Listing
October 2019

Low root/shoot (R/S) biomass ratio can be an indicator of low cadmium accumulation in the shoot of Chinese flowering cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) cultivars.

Environ Sci Pollut Res Int 2018 Dec 27;25(36):36328-36340. Epub 2018 Oct 27.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou, 510632, China.

Chinese flowering cabbage is a commonly consumed vegetable that accumulates Cd easily from Cd-contaminated soils. Cultivations of low-Cd cultivars are promising strategies for food safety, but low-Cd-accumulating mechanisms are not fully elucidated. To address this issue, 37 cultivars were screened to identify high- and low-Cd cultivars upon exposure to sewage-irrigated garden soil pretreated with different Cd concentrations (1.81, 2.90, and 3.70 mg kgdry soil). The results showed that shoot Cd concentrations differed among the cultivars by maximum degrees of 2.67-, 3.71-, and 3.00-fold under control and treatments, respectively. Soil-pot trial and hydroponic trial found no significant difference in Cd and Ca mobilization, uptake, and transport ability by root per weight between high- and low-Cd cultivars. Interestingly, a stable R/S ratio difference among cultivars (p < 0.01) was observed, and the cultivar variation of Cd accumulation in shoots was mainly dependent on their R/S ratios. R/S ratio was also statistically positively associated with Cd and Ca accumulation in high- and low-Cd cultivars (p < 0.05), both in soil and hydroponics culture. This was mainly due to the lower root biomass of low-Cd cultivars resulted in lower total release of root exudates, lower total Cd and Ca mobilization in rhizosphere soil, and lower total Cd and Ca uptake and transport. The higher shoot biomass of low-Cd cultivars also has dilution effects on Cd concentration in shoot. Overall, low R/S ratio may be regarded as a direct and efficient indicator of low Cd accumulation in the shoot of Chinese flowering cabbage. These findings provided the possibilities to screening low-Cd cultivars using their R/S ratio.
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http://dx.doi.org/10.1007/s11356-018-3566-xDOI Listing
December 2018

Exogenous Glycinebetaine Promotes Soil Cadmium Uptake by Edible Amaranth Grown during Subtropical Hot Season.

Int J Environ Res Public Health 2018 08 21;15(9). Epub 2018 Aug 21.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou 511443, China.

Exogenous glycinebetaine treatment is an effective measure for preventing crops from being exposed to drought and high temperature; however, the effects of this approach on the soil Cd uptake and accumulation by crops remain unclear. Pot experiments were conducted in this study to analyze the effect of glycinebetaine on the soil Cd uptake and accumulation by edible amaranth cultivated in Cd-contaminated soil. Results revealed that after exogenous glycinebetaine treatment on amaranth leaves during the vigorous growth period, the plant biomass, the Cd concentrations in the roots and shoots, and the Cd translocation factor (TF) were significantly higher than those of the control group. The highest Cd concentrations in the roots and shoots and the TF were higher by 91%, 96% and 23.8%, respectively, than the corresponding values in the control group. In addition, exogenous glycinebetaine treatment significantly increased leaf chlorophyll content and promoted the photosynthesis of edible amaranth. Consequently, the contents of soluble sugar, dissolved organic carbon, and low-molecular-weight organic acids significantly increased in the rhizosphere, resulting in Cd mobilization. Significant positive correlations were observed among the contents of leaf chlorophyll, Mg, Fe, pectin and Ca. Given that Cd shares absorption and translocation channels with these elements, we speculated that the increased leaf chlorophyll and pectin contents promoted the absorption and accumulation of Mg, Fe and Ca, which further promoted the absorption and translocation of Cd. These results indicated that exogenous glycinebetaine treatment during hot season would aggravate the health risks of crops grown in Cd-contaminated soils.
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http://dx.doi.org/10.3390/ijerph15091794DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164276PMC
August 2018

Low-Cd tomato cultivars (Solanum lycopersicum L.) screened in non-saline soils also accumulated low Cd, Zn, and Cu in heavy metal-polluted saline soils.

Environ Sci Pollut Res Int 2018 Sep 24;25(27):27439-27450. Epub 2018 Jul 24.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou, 510632, China.

Many reclaimed tidal flat soils feature high salinity and heavy metal (HM) accumulation. Consumption of vegetables cultivated in this type of cropland may cause health risks. Low-Cd tomato cultivars (Solanum lycopersicum L.) were identified in non-saline soil in our previous studies (Tan et al. 2014). However, further research should determine whether these low-Cd cultivars will maintain in the repeatability and stability in saline soil and whether they have low accumulation abilities for accompanying metals (such as Zn and Cu). A soil-pot trial was implemented to measure Cd, Zn, and Cu concentrations in low- and high-Cd cultivars of both common and cherry-type tomatoes grown on HM-polluted reclaimed tidal flat saline soil. Then, cultivar differences in dissolution of Cd, Zn, and Cu in soil and their uptake and redistribution in plants were analyzed. Results showed that the cherry type accumulated more Cd, Zn, and Cu than the common type. Low-Cd cultivars of both types in saline soil accumulated low concentrations of Cd, Zn, and Cu in fruits. Low HM accumulation in fruits is partly attributed to a low root/shoot (R/S) biomass ratio. Low amounts of soil HMs were dissolved because of the low level of rhizosphere organic compounds, which possibly decreased HM uptake by the roots. Low-Cd cultivars of both tomato types had a higher ability to retain HMs in the roots than their high-Cd cultivars. These findings may provide a scientific guidance for the safe cultivation of HM-polluted saline soils.
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http://dx.doi.org/10.1007/s11356-018-2776-6DOI Listing
September 2018

Effect of Phosphate-Solubilizing Bacteria on the Mobility of Insoluble Cadmium and Metabolic Analysis.

Int J Environ Res Public Health 2018 06 25;15(7). Epub 2018 Jun 25.

School of Environment, Jinan University, Guangzhou 511443, China.

Phosphate-solubilizing bacteria (PSB) can promote plant growth by dissolving insoluble phosphate. Therefore, PSB may have the potential to improve the mobility of heavy metals in soils and enhance phytoextraction. This study isolated a few PSB strains that could dissolve CdCO₃ and solid Cd in soil. Two typical PSB, namely, high- and low-Cd-mobilizing PSB ( gim-3 and qh-35, respectively), were selected to analyze the metabolic profiles, metabolic pathways, and mechanisms of mobilization of insoluble Cd. A total of 34 metabolites secreted by the two PSB strains were identified. Gluconic acid was the main contributor to Cd dissolution (42.4%) in high-Cd-mobilizing PSB. By contrast, gluconic acid was not secreted in low-Cd-mobilizing PSB. Metabolic pathway analysis showed that gluconic acid was produced by the peripheral direct oxidation pathway. Hence, PSB with peripheral direct oxidation pathway were likely to have high-Cd-mobilizing capacity.
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http://dx.doi.org/10.3390/ijerph15071330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6068833PMC
June 2018

Response of edible amaranth cultivar to salt stress led to Cd mobilization in rhizosphere soil: A metabolomic analysis.

Environ Pollut 2018 Oct 31;241:422-431. Epub 2018 May 31.

School of Environment, Key Laboratory of Environmental Pollution and Health of Guangdong Province, Jinan University, Guangzhou, 510632, China.

The present study aimed to investigate the metabolic response of edible amaranth cultivars to salt stress and the induced rhizosphere effects on Cd mobilization in soil. Two edible amaranth cultivars (Amaranthus mangostanus L.), Quanhong (low-Cd accumulator; LC) and Liuye (high-Cd accumulator; HC), were subject to salinity treatment in both soil and hydroponic cultures. The total amount of mobilized Cd in rhizosphere soil under salinity treatment increased by 2.78-fold in LC cultivar and 4.36-fold in HC cultivar compared with controls, with 51.2% in LC cultivar and 80.5% in HC cultivar being attributed to biological mobilization of salinity. Multivariate statistical analysis generated from metabolite profiles in both rhizosphere soil and root revealed clear discrimination between control and salt treated samples. Tricarboxylic acid cycle in root was up-regulated to cope with salinity treatment, which promoted release of organic acids from root. The increased accumulation of organic acids in rhizosphere under salt stress obviously promoted soil Cd mobility. These results suggested that salinity promoted release of organic acids from root and enhanced soil Cd mobilization and accumulation in edible amaranth cultivar in soil culture.
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http://dx.doi.org/10.1016/j.envpol.2018.05.018DOI Listing
October 2018

Impact of osmoregulation on the differences in Cd accumulation between two contrasting edible amaranth cultivars grown on Cd-polluted saline soils.

Environ Pollut 2017 May 3;224:89-97. Epub 2017 Mar 3.

Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou, 510632, China.

This study aimed to investigate the difference of osmoregulation between two edible amaranth cultivars, Liuye (high Cd accumulator) and Quanhong (low Cd accumulator), under salinity stress and determine the effects of such difference on Cd accumulation. A pot experiment was conducted to expose the plants to sewage-irrigated garden soil (mean 2.28 mg kg Cd) pretreated at three salinity levels. Under salinity stress, the concentrations of Cd in the two cultivars were significantly elevated compared with those in the controls, and the Cd concentration in Liuye was statistically higher than that in Quanhong (p < 0.05). Salinity-induced osmoregulation triggered different biogeochemical processes involved in Cd mobilization in the rhizosphere soil, Cd absorption, and translocation by the two cultivars. Rhizosphere acidification induced by an imbalance of cation over anion uptake was more serious in Liuye than in Quanhong, which obviously increased soil Cd bioavailability. Salinity-induced injuries in the cell wall pectin and membrane structure were worse in Liuye than in Quanhong, increasing the risk of Cd entering the protoplasts. The chelation of more cytoplasmic Cd with Cl ions in the roots of Liuye promoted Cd translocation into the shoots. Furthermore, the less organic solutes in the root sap of Liuye than in that of Quanhong also favored Cd translocation into the shoots. Hence, osmoregulation processes can be regarded as important factors in reducing Cd accumulation in crop cultivars grown on saline soils.
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http://dx.doi.org/10.1016/j.envpol.2016.12.067DOI Listing
May 2017

Use of low-calcium cultivars to reduce cadmium uptake and accumulation in edible amaranth (Amaranthus mangostanus L.).

Chemosphere 2017 Mar 19;171:588-594. Epub 2016 Dec 19.

School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.

This study aimed to investigate the mechanism of low Cd accumulation in crops using edible amaranth (Amaranthus mangostanus L.) as a model. Fifteen amaranth cultivars were grown in long-term contaminated soil, and the differences in soil Cd mobilization, root uptake, and root-shoot translocation between low- and high-Cd accumulating cultivars were examined. The transport pathways of Cd across the root were further identified in Hoagland nutrient solution using the Ca channel blocker La, the ATP inhibitor 2, 4-dinitrophenol (DNP), and a nutrition-deficient culture. Cd concentrations in amaranth cultivars varied about six-fold and showed an elevated trend as the concentration of Ca and Zn increased (p < 0.01), but did not exhibit any correlation with Mg and Fe. The concentrations of essential metals (Ca, Mg, Zn, and Fe) in the rhizosphere of low-Cd cultivars were significantly lower than those of high-Cd cultivars, and decreased with decreasing levels of soluble rhizosphere exudates. These findings indicated that low co-mobilization of Cd with essential metals mediated by root-induced exudates of low-Cd cultivars contributed to its low accumulation in amaranth. Uptake of Cd was inhibited along with Ca by La and DNP, but was promoted by Ca or Fe deficiency treatment. Therefore, the Ca pathway is likely the mode of Cd entry into amaranth roots, although Zn and Fe transporters may also be involved. Low-Ca cultivars exhibited lower Cd uptake capability than high-Ca cultivars. The low translocation efficiency of Cd from root to shoot also contributed to its low content accumulation in edible parts of amaranth.
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http://dx.doi.org/10.1016/j.chemosphere.2016.12.085DOI Listing
March 2017

Leaching heavy metals from the surface soil of reclaimed tidal flat by alternating seawater inundation and air drying.

Chemosphere 2016 Aug 27;157:262-70. Epub 2016 May 27.

Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou, 510632, China.

Leaching experiments were conducted in a greenhouse to simulate seawater leaching combined with alternating seawater inundation and air drying. We investigated the heavy metal release of soils caused by changes associated with seawater inundation/air drying cycles in the reclaimed soils. After the treatment, the contents of all heavy metals (Cd, Pb, Cr, and Cu), except Zn, in surface soil significantly decreased (P < 0.05), with removal rates ranging from 10% to 51%. The amounts of the exchangeable, carbonate, reducible, and oxidizable fractions also significantly decreased (P < 0.05). Moreover, prolonged seawater inundation enhanced the release of heavy metals. Measurement of diffusive gradients in thin films indicated that seawater inundation significantly increased the re-mobility of heavy metals. During seawater inundation, iron oxide reduction induced the release of heavy metals in the reducible fraction. Decomposition of organic matter, and complexation with dissolved organic carbon decreased the amount of heavy metals in the oxidizable fraction. Furthermore, complexation of chloride ions and competition of cations during seawater inundation and/or leaching decreased the levels of heavy metals in the exchangeable fraction. By contrast, air drying significantly enhanced the concentration of heavy metals in the exchangeable fraction. Therefore, the removal of heavy metals in the exchangeable fraction can be enhanced during subsequent leaching with seawater.
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http://dx.doi.org/10.1016/j.chemosphere.2016.05.019DOI Listing
August 2016

Use of flue gas desulfurization gypsum for leaching Cd and Pb in reclaimed tidal flat soil.

Environ Sci Pollut Res Int 2016 Apr 13;23(8):7840-8. Epub 2016 Jan 13.

Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou, 510632, China.

A soil column leaching experiment was conducted to eliminate heavy metals from reclaimed tidal flat soil. Flue gas desulfurization (FGD) gypsum was used for leaching. The highest removal rates of Cd and Pb in the upper soil layers (0-30 cm) were 52.7 and 30.5 %, respectively. Most of the exchangeable and carbonate-bound Cd and Pb were removed. The optimum FGD gypsum application rate was 7.05 kg·m(-2), and the optimum leaching water amount for the application was 217.74 L·m(-2). The application of FGD gypsum (two times) and the extension of the leaching interval time to 20 days increased the heavy metal removal rate in the upper soil layers. The heavy metals desorbed from the upper soil layers were re-adsorbed and fixed in the 30-70 cm soil layers.
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http://dx.doi.org/10.1007/s11356-016-6058-xDOI Listing
April 2016

Effects of freshwater leaching on potential bioavailability of heavy metals in tidal flat soils.

Environ Geochem Health 2016 Feb 7;38(1):99-110. Epub 2015 Mar 7.

School of Environment, Jinan University, Guangzhou, 510632, China.

Leaching experiments were conducted to investigate the effects of desalination levels and sediment depths on potential bioavailability of heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in tidal flat soils. The data showed that both the desalination levels (p < 0.001) and soil depths (p < 0.001) had significant effects on the concentrations of acid-volatile sulfide (AVS). AVS concentrations generally exhibited increasing trends with an increase in depth and decreasing trends with enhanced desalination levels. The desalination levels had significant (p < 0.05) effects on the concentrations of simultaneously extracted metal (SEM; Cd, Cr, Cu, Fe, Mn, Pb, and Zn). Moreover, the concentrations of SEM (Cd, Cr, Cu, Fe, Mn, Pb, and Zn) generally tended to decrease with an increase in the desalination level. The desalination treatment significantly reduced the ratios of SEM/AVS compared with control. However, the ratios of SEM/AVS increased with enhanced desalination levels in treatments. Results reveal that low desalination treatment is better for reducing toxicity to benthic organisms than high desalination treatment. Since these reclaimed tidal flats with low desalinisation are suitable for saline water aquaculture, transforming the present land use of reclaimed tidal flats from fresh water aquaculture into saline water aquaculture may reduce health risk of heavy metals remained in sediments. These results will also contribute to our understanding of the dynamic behavior of heavy metals in the reclamation of tidal flats during leaching and the role of the ratio of SEM/AVS predictions on assessing the ecological risks of reclaimed tidal flats.
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http://dx.doi.org/10.1007/s10653-015-9688-xDOI Listing
February 2016

Plant uptake and enhanced dissipation of di(2-ethylhexyl) phthalate (DEHP) in spiked soils by different plant species.

Int J Phytoremediation 2014 ;16(6):609-20

This study was conducted to investigate the uptake, accumulation and the enhanced dissipation of di(2-ethylhexyl) phthalate (DEHP) spiked in soil (with a concentration of 117.4 +/- 5.2 mg kg(-1)) by eleven plants including eight maize (Zea mays) cultivars and three forage species (alfalfa, ryegrass and teosinte). The results showed that, after 40 days of treatment, the removal rates of DEHP ranged from 66.8% (for the control) to 87.5% (for the maize cultivar of Huanong-1). Higher removal rate was observed during the first 10 days than the following days. Plants enhanced significantly the dissipation of DEHP in soil. Enhanced dissipation amount in planted soil was 13.3-122 mg pot(-1) for DEHP, and a net removal of 2.2%-20.7% of the initial DEHP was obtained compared with non-plant soil. The contribution of plant uptake to the total enhanced dissipation was < 0.3%, and the enhanced dissipation of soil DEHP might be derived from plant-promoted biodegradation and sorption stronger to the soil. Nevertheless, the capability in accumulation and enhanced dissipation of DEHP from spiked soils varied within different species and cultivars.
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http://dx.doi.org/10.1080/15226514.2013.803021DOI Listing
July 2014

Identification of heavy metal sources in the reclaimed farmland soils of the pearl river estuary in China using a multivariate geostatistical approach.

Ecotoxicol Environ Saf 2014 Jul 7;105:7-12. Epub 2014 May 7.

Department of Environmental Engineering, Jinan University, Guangzhou 510632, China; Key Laboratory of Water/Soil Toxic Pollutants Control and Bioremediation, Department of Education of Guangdong Province, Guangzhou 510632, China.

Heavy metals in the reclaimed farmland soils of the Pearl River Estuary in China have attracted much attention because of the health risk posed to local residents. The identification of heavy metal sources in these soils is necessary to reduce their health risk. Reclaimed farmland soil samples were collected from 144 sites in the Pearl River Estuary and the contents of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) were determined. All these heavy metals showed concentrations substantially higher than their background values, indicating possible anthropogenic pollution. The results of a multivariate geostatistical method demonstrate that grouped Cd, Cr, and Cu were mainly controlled by chemical fertilizers. Grouped Pb and Zn were the most severely impacted by atmospheric deposition from Guangzhou and Foshan, and Ni was primarily impacted by electroplating factories' wastewater discharge.
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http://dx.doi.org/10.1016/j.ecoenv.2014.04.003DOI Listing
July 2014

[Synthesis and characterization of protocatechuic acid derivants].

Zhongguo Zhong Yao Za Zhi 2013 Jan;38(2):208-11

Beijing University of Chinese Medicine, Beijing 100102, China.

To explore the effects of protocatechuic acid (PCA) and its derivants on angiogenesis of the chick embryo chorioallantoic membrane (CAM) and scavenging DPPH radical in vitro. The protection of benzyl and alkaline hydrolysis of benzyl ester were employed. The structures of PCA-1, PCA-2 and PCA-3, the derivates of PCA, were elucidated by 1H, 13C-NMR and MS data The bioactivity of PCA and its derivants was evaluated on the models of DPPH radical and chick embryo chorioallantoic membrane (CAM), respectively. PCA and PCA-1 showed the best activity of scavenging DPPH radical among all the compounds. In contrast to PCA-2, PCA and PCA-3 displayed inhibition to angiogenesis (P < 0.001). Pyrocatechol hydroxyl is the active site of PCA on scavenging DPPH radical in vitro. PCA with carboxyl and without pyrocatechol hydroxyl seems to show promotion to angiogenesis, but it needs more evidences.
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January 2013

[Salinity change and its impact on heavy metals during beach soil leaching and desalination].

Huan Jing Ke Xue 2011 Jul;32(7):2087-91

Key Laboratory of Water/Soil Toxic Pollutants Control and Bioremediation, Department of Education of Guangdong Province, Department of Environmental Engineering, Jinan University, Guangzhou 510632, China.

The salinity ion in soil pore water and the heavy metal content in soil as well as the heavy metal speciation were investigated in various stages of desalination during an experiment of leaching beach soil. Results show that salinity ion including Na+, K+, Mg2+, Ca2+, Cl- and SO4(2-) decreased by 80.3%, 73.5%, 86.6%, 90%, 81.8%, 98.2%. respectively compared to pre-leaching. The amount of total salt decreased by 81.6%. However, the main chemical compound in pore water was NaCl throughout the leaching experiment. The pH value of pore water increased with leaching time. Besides, the reductions of heavy metals after leaching were: Cd 26.6%, Pb 22.8%, Cu 16.9%, Cr 7.9%, Zn 9.1%. The concentrations of Pb, Cr, Cu, Zn and Cd in carbonate bound form decreased by 77.8%, 61.7%, 68.4%, 67.1% and 7.1% respectively. The contents of Cd and Pb bound to Fe-Mn oxide decreased by 49.1%, 23.5% respectively. The different mobility of salinity ions in the pore water resulted in the proportion change of each ion. Meanwhile the Eh value of the soil changed in the leaching process. All these factors resulted in the change of heavy metal speciation and the removal of heavy metals in the soil.
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July 2011