复合污染土壤上几种叶类蔬菜对Cd和As的富集效应
|
摘要
【目的】不同蔬菜镉、砷富集系数各异,对镉和砷污染土壤的响应也不同。研究复合污染土壤上不同叶类蔬菜对Cd和As的积累效应,为轻度–中度Cd和As污染土壤的合理与安全利用提供适宜的蔬菜种类。【方法】采集了西安市12个污染程度不同的菜地耕层土壤,于2015年3月6日—5月26日在西北农林科技大学资源环境学院遮雨大棚内进行了盆栽试验。供试7种叶菜,包括菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿。蔬菜收获后,测量了蔬菜产量、Cd和As含量与吸收累积量,计算了蔬菜对Cd和As的富集系数等,并用线性回归模型研究了不同蔬菜栽培的土壤Cd和As安全临界值。【结果】镉污染土壤(0.6～2.4 mg/kg)对大多数蔬菜生物量有抑制效应,中、低浓度镉砷复合污染(Cd 1.0～2.4 mg/kg,As 24.9～26.8 mg/kg)对供试蔬菜生长没有叠加效应。镉污染土壤上,菠菜、油菜、苋菜叶、生菜可食部Cd含量均超出食品安全限量标准(0.2 mg/kg),其中菠菜和油菜Cd最高超标4倍以上;而茼蒿和空心菜茎秆Cd未超标。虽然供试蔬菜砷含量随着土壤砷含量增加有升高趋势,但叶菜As含量没有超标。7种蔬菜Cd富集系数为0.083～0.491,高低顺序为油菜、菠菜、生菜和苋菜叶>油麦菜、苋菜茎和空心菜叶>空心菜茎和茼蒿。菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿土壤Cd安全临界值分别为0.33、0.38、0.46、1.15、0.59～1.79、1.49～8.16和8.98～17.11 mg/kg,其中菠菜、油菜和生菜阈值与现行标准(0.3～0.6 mg/kg)相当,而油麦菜、苋菜、空心菜和茼蒿均大于土壤重金属污染限量值。As富集系数为0.002～0.006,空心菜叶和茼蒿叶片As富集系数显著高于其他蔬菜。7种蔬菜的土壤As临界阈值分别为62.31、70.35、70.21、67.41、67.86～90.43、57.21～75.70和72.43～105.06 mg/kg,均高于现行标准(25 mg/kg)。【结论】中等程度的Cd和As复合污染土壤上,Cd对蔬菜的生长有显著的抑制,As与Cd没有叠加作用。不同蔬菜的产量、污染程度和安全阈值等有显著差异,因此选择低富集、抗污染蔬菜品种是利用中低重金属污染土壤的一条可行途径。空心菜和茼蒿对Cd富集系数低,可推荐在中、低污染土壤上种植。
【Objectives】The response of vegetable to soil cadmium(Cd) and arsenic(As) stress and their enrichment and tolerance varies significantly. The uptake and accumulation characteristics of Cd and As of some leafy vegetables cultured in light to medium Cd and As co-contaminated soils were investigated, aiming to provide reference for the rational and safe use of light and medium contaminated soils.【Methods】Twelve Cd &As polluted soils were collected from the plough layers of vegetable fields in Xi'an suburbs, and seven kinds of leafy vegetables were assessed in the pot experiment, which was conducted in the greenhouse of the College of Resources and Environment of Northwest A&F University from March to May of 2015. The tested vegetables were: spinach(Spinacia oleracea L.), cos lettuce(Lactuca sativa L.), cole, Romaine lettuce(Lactuca sativa L.var. longifolia), edible amaranth(Amaranthus mangostanus L.), water spinach(Ipomoea aquatica forsk) and garland chrysanthemum(Chrysanthemum coronarium L.). The vegetable yields, Cd and As contents were determined, the safety thresholds of soil pollution of Cd & As were calculated using linear regression models.【Results】The soil Cd polluting level of 0.6–2.4 mg/kg reduced the biomass of most vegetables, medium or low co-contamination of Cd and As(Cd 1.1–2.4 mg/kg, As 24.9–26.8 mg/kg) did not exacerbate the inhibition.On the medium co-contaminated soil, Cd contents in the edible parts of spinach, cole, amaranth leaves, and lettuce exceeded the food safety critical value(0.2 mg/kg), and the Cd contents in spinach and cole were even 4 folds beyond the standards, while those of water spinach stem and garland chrysanthemum did not exceed the standard. Although the arsenic contents of all tested vegetables increased with increasing of soil arsenic concentrations, they did not exceed the standard. The enrichment coefficients of Cd in the seven kinds of vegetables were 0.083–0.491, with descend order of cole, spinach, cos lettuce, edible amaranth leaf > Romaine lettuce, edible amaranth stem, water spinach leaf > water spinach stem and garland chrysanthemum. The safety thresholds of soil Cd for spinach, cole, cos lettuce, Romaine lettuce, edible amaranth, water spinach and garland chrysanthemum were 0.33, 0.38, 0.46, 1.15, 0.59–1.79, 1.49–8.16 and 8.98–17.11 mg/kg, respectively. Among them, the thresholds of spinach, cole and lettuce were similar to the current standards(0.3–0.6 mg/kg), while the Romaine lettuce, edible amaranth, water spinach, and garland chrysanthemum were all greater than the soil heavy metal limitation values. As enrichment coefficient was 0.002–0.006, and the As enrichment coefficient of leaves of water spinach and garland chrysanthemum were significantly higher than those of others. The critical thresholds of soil As for the seven kinds of vegetables were 62.31, 70.35, 70.21, 67.41, 67.86–90.43,57.21–75.70 and 72.43–105.06 mg/kg, respectively, which all were higher than the current standards(25 mg/kg).【Conclusions】The cadmium and arsenic enrichment coefficients of vegetables varied significantly, and so were their responses to light-mild cadmium-arsenic co-contamination soils. Water spinach and garland chrysanthemum had low Cd enrichment coefficients and could be recommended for cultivation on mild polluted soil, while spinach and cos lettuce should not be chosen because of the high enrichment of Cd from soil.
【Objectives】The response of vegetable to soil cadmium(Cd) and arsenic(As) stress and their enrichment and tolerance varies significantly. The uptake and accumulation characteristics of Cd and As of some leafy vegetables cultured in light to medium Cd and As co-contaminated soils were investigated, aiming to provide reference for the rational and safe use of light and medium contaminated soils.【Methods】Twelve Cd &As polluted soils were collected from the plough layers of vegetable fields in Xi'an suburbs, and seven kinds of leafy vegetables were assessed in the pot experiment, which was conducted in the greenhouse of the College of Resources and Environment of Northwest A&F University from March to May of 2015. The tested vegetables were: spinach(Spinacia oleracea L.), cos lettuce(Lactuca sativa L.), cole, Romaine lettuce(Lactuca sativa L.var. longifolia), edible amaranth(Amaranthus mangostanus L.), water spinach(Ipomoea aquatica forsk) and garland chrysanthemum(Chrysanthemum coronarium L.). The vegetable yields, Cd and As contents were determined, the safety thresholds of soil pollution of Cd & As were calculated using linear regression models.【Results】The soil Cd polluting level of 0.6–2.4 mg/kg reduced the biomass of most vegetables, medium or low co-contamination of Cd and As(Cd 1.1–2.4 mg/kg, As 24.9–26.8 mg/kg) did not exacerbate the inhibition.On the medium co-contaminated soil, Cd contents in the edible parts of spinach, cole, amaranth leaves, and lettuce exceeded the food safety critical value(0.2 mg/kg), and the Cd contents in spinach and cole were even 4 folds beyond the standards, while those of water spinach stem and garland chrysanthemum did not exceed the standard. Although the arsenic contents of all tested vegetables increased with increasing of soil arsenic concentrations, they did not exceed the standard. The enrichment coefficients of Cd in the seven kinds of vegetables were 0.083–0.491, with descend order of cole, spinach, cos lettuce, edible amaranth leaf > Romaine lettuce, edible amaranth stem, water spinach leaf > water spinach stem and garland chrysanthemum. The safety thresholds of soil Cd for spinach, cole, cos lettuce, Romaine lettuce, edible amaranth, water spinach and garland chrysanthemum were 0.33, 0.38, 0.46, 1.15, 0.59–1.79, 1.49–8.16 and 8.98–17.11 mg/kg, respectively. Among them, the thresholds of spinach, cole and lettuce were similar to the current standards(0.3–0.6 mg/kg), while the Romaine lettuce, edible amaranth, water spinach, and garland chrysanthemum were all greater than the soil heavy metal limitation values. As enrichment coefficient was 0.002–0.006, and the As enrichment coefficient of leaves of water spinach and garland chrysanthemum were significantly higher than those of others. The critical thresholds of soil As for the seven kinds of vegetables were 62.31, 70.35, 70.21, 67.41, 67.86–90.43,57.21–75.70 and 72.43–105.06 mg/kg, respectively, which all were higher than the current standards(25 mg/kg).【Conclusions】The cadmium and arsenic enrichment coefficients of vegetables varied significantly, and so were their responses to light-mild cadmium-arsenic co-contamination soils. Water spinach and garland chrysanthemum had low Cd enrichment coefficients and could be recommended for cultivation on mild polluted soil, while spinach and cos lettuce should not be chosen because of the high enrichment of Cd from soil.
引文
[1]Khan S,Cao Q,Zheng Y M,et al.Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing,China[J].Environmental Pollution,2008,152(3):686-692.
[2]Song B,Lei M,Chen T B,et al.Assessing the health risk of heavy metals in vegetables to the general population in Beijing,China[J].Journal of Environmental Sciences,2009,21(12):1702-1709.
[3]Zhuang P,Mcbride M B,Xia H P,et al.Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine,South China[J].Science of the Total Environment,2009,407(5):1551-1561.
[4]Yang Q W,Xu Y,Liu S J,et al.Concentration and potential health risk of heavy metals in market vegetables in Chongqing,China[J].Ecotoxicology and Environmental Safety,2011,74(6):1664-1669.
[5]Yang L Q,Huang B,Hu W Y,et al.Assessment and source identification of trace metals in the soils of greenhouse vegetable production in eastern China[J].Ecotoxicology and Environmental Safety,2013,97:204-209.
[6]Xiao Q,Zong Y T,Lu S G.Assessment of heavy metal pollution and human health risk in urban soils of steel industrial city(Anshan),Liaoning,Northeast China[J].Ecotoxicology and Environmental Safety,2015,120:377-385.
[7]Hu J L,Wu F Y,Wu S C,et al.Phytoavailability and phytovariety codetermine the bioaccumulation risk of heavy metal from soils,focusing on Cd-contaminated vegetable farms around the Pearl River Delta,China[J].Ecotoxicology and Environmental Safety,2013,91:18-24.
[8]Alexander P D,Alloway B J,Dourado A M.Genotypic variations in the accumulation of Cd,Cu,Pb and Zn exhibited by six commonly grown vegetables[J].Environmental Pollution,2006,144(3):736-745.
[9]Li Q S,Cai S S,Mo C H,et al.Toxic effects of heavy metals and their accumulation in vegetables grown in a saline soil[J].Ecotoxicology and Environmental Safety,2010,73(1):84-88.
[10]Xu L,Lu X,Wang J H,et al.Accumulation status,sources and phytoavailability of metals in greenhouse vegetable production systems in Beijing,China[J].Ecotoxicology and Environmental Safety,2015,122:214-220.
[11]Lu J H,Yang X P,Meng X C,et al.Predicting cadmium safety thresholds in soils based on cadmium uptake by Chinese cabbage[J].Pedosphere,2017,27(3):475-481.
[12]Yang Y,Zhang F S,Li H F,et al.Accumulation of cadmium in the edible parts of six vegetable species grown in Cd-contaminated soils[J].Journal of Environmental Management,2009,90(2):1117-1122.
[13]Li X H,Zhou Q X,Wei S H,et al.Identification of cadmiumexcluding welsh onion(Allium fistulosum L.)cultivars and their mechanisms of low cadmium accumulation[J].Environmental Science and Pollution Research,2012,19(5):1773-1780.
[14]Shao T J,Pan L H,Chen Z Q,et al.Content of heavy metal in the dust of leisure squares and its health risk assessment-A case study of yanta district in Xi’an[J].International Journal of Environmental Research&Public Health,2018,(15):394-417.
[15]Chen X D,Lu X W,Li L Y,et al.Spatial distribution and contamination assessment of heavy metals in urban topsoil from inside the Xi’an second ringroad,NW China[J].Microchemical Journal,2013,(68):1979-1988.
[16]Chen H,Lu X W,Gao T N,et al.Identifying hot-spots of metal contamination in campus dust of Xi’an,China[J].International Journal of Environmental Research and Public Health,2016,(13):1-16.
[17]Lu X W,Zhang X L,Li L Y,et al.Assessment of metals pollution and health risk in dust from nursery schools in Xi’an,China[J].Environmental Research,2014,128:27-34.
[18]Chen Y P,Zheng Y J,Liu Q,et al.Atmospheric deposition exposes Qinling pandas to toxic pollutants[J].Ecological Applications,2017,(2):343-348.
[19]Deng W B,Li X X,An Z S,et al.Identification of sources of metal in the agricultural soils of the Guanzhong plain,northwest china[J].Environmental Toxicology and Chemistry,2017,(6):1510-1516.
[20]李雪芳,王文岩,上官宇先,等.西安市郊菜地土壤重金属污染及其与蔬菜重金属质量分数的相关性[J].西北农业学报,2014,23(8):173-181.Li X F,Wang W Y,Shangguan Y X,et al.Relationship of heavy metal pollution in soil and their mass fraction in vegetables in Xi’An city suburb[J].Acta Agriculturae Boreali-occidentalis Sinica,2014,23(8):173-181.
[21]李雪芳,王林权,尚浩博,等.小白菜和小青菜对镉、汞、砷的富集效应及影响因素[J].北方园艺,2014,(1):16-21.Li X F,Wang L Q,Shang H B,et al.The enrichment effect of Cd,Hg and As on brassica chinensis and Brassica pekinensis and its influencing factors[J].Northern Horticulture,2014,(1):16-21.
[22]Li X P,Feng L N,et al.Spatial distribution of hazardous elements in urban topsoils surrounding Xi’an industrial areas,(NW,China):Controlling factors and contamination assessments[J].Journal of Hazardous Materials,2010,174:662-669.
[23]Zhang H H,Chen J J,Zhu L,et al.Transfer of cadmium from soil to vegetable in the Pearl River Delta area,South China[J].PLoS One,2014,9(9):1-11.
[24]GB2762-2017,食品中污染物限量[S].GB2762-2017,Contaminant limit in food[S].
[25]Yang Y,Chen W P,Wang M E,et al.Regional accumulation characteristics of cadmium in vegetables:influencing factors,transfer model and indication of soil threshold content[J].Environmental Pollution,2016,219:1036-1043.
[26]Wang X P,Shan X Q,Zhang S Z,et al.A model for evaluation of the phytoavailability of trace elements to vegetables under the field conditions[J].Chemosphere,2004,55(6):811-822.
[27]Qiu Q,Wang Y T,Yang Z Y,et al.Responses of different Chinese flowering cabbage(Brassica parachinensis L.)cultivars to cadmium and lead exposure:screening for Cd+Pb pollution-safe cultivars[J].CLEAN-Soil Air Water,2011,39(11):925-932.
[28]Chen Y,Li T Q,Han X,et al.Cadmium accumulation in different pakchoi cultivars and screening for pollution-safe cultivars[J].Journal of Zhejiang University-Science B,2012,13(6):494-502.
[29]Wang X,Shi Y,Chen X,et al.Screening of Cd-safe genotypes of Chinese cabbage in field condition and Cd accumulation in relation to organic acids in two typical genotypes under long-term Cd stress[J].Environmental Science and Pollution Research,2015,(22):16590-16599.
[30]Girish C,Saifullah,Nanthi B,et al.Cellular mechanisms in higher plants governing tolerance to cadmium toxicity[J].Critical Reviewsin Plant Sciences,2014,33(5):374-391.
[31]Verbruggen N,Hermans C,Schat H.Mechanisms to cope with arsenic or cadmium excess in plants[J].Current Opinion in Plant Biology,2009,(12):364-372.
[32]Meng Y,Zhang L,Wang L Q,et al.Antioxidative enzymes activity and thiol metabolism in three leafy vegetables under Cd stress[J].Ecotoxicology and Environmental Safety,2019,173:214-224.
[33]Akhter F,McGarvey B,Macfie S M.Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors[J].Journal of Plant Physiology,2012,169(18):1821-1829.
[34]Mendoza-Cózatl D,Loza-Tavera H,Hernández-Navarro A,et al.Sulfur assimilation and glutathione metabolism under cadmium stress in yeast,protists and plants[J].FEMS Microbiology Reviews,2005,29(4):653-671.
[35]Souhir S,Alessandro F,Clarissa L,et al.Analysis of cadmium translocation,partitioning and tolerance in six barley(Hordeum vulgare L.)cultivars as a function of thiol metabolism[J].Biology and Fertility of Soils,2015,51(3):311-320.
[36]Negrin V L,Teixeira B,Godinho R M,et al.Phytochelatins and monothiols in salt marsh plants and their relation with metal tolerance[J].Marine Pollution Bulletin,2017,121(1-2):78-84.
[37]文典,胡霓红,赵凯,等.小白菜对土壤中5种重金属的富集特征及土壤安全临界值的研究[J].热带作物学报,2012,(11):1942-1948.Wen D,Hu N H,Zhao K,et al.Five kinds of heavy metals enrichment characteristics in Pakchoi(Brassica chinensis L.)and the critical values in the soil for Pakchoi production[J].Chinese Journal of Tropical Crops,2012,(11):1942-1948.
[38]赵勇,李红娟,孙治强.土壤、蔬菜Cd污染相关性分析与土壤污染阈限值研究[J].农业工程学报,2006,(7):149-153.Zhao Y,Li H J,Sun Z Q.Correlation analysis of Cd pollution in vegetables and soils and the soil pollution threshold[J].Transactions of the CSAE,2006,(7):149-153.
[39]Wang J L,Yuan J G,Yang Z Y,et al.Variation in cadmium accumulation among 30 cultivars and cadmium subcellular distribution in 2 selected cultivars of water spinach(Ipomoea aquatica Forsk.)[J].Journal of Agricultural and Food Chemistry,2009,57(19):8942-8949.
[40]Cui Y J,Zhu Y G,Zhai R H,et al.Transfer of metals from soil to vegetables in an area near a smelter in Nanning,China[J].Environment International,2004,30(6):785-791.
[41]Huang R Q,Gao S F,Wang W L,et al.Soil arsenic availability and the transfer of soil arsenic to crops in suburban areas in Fujian Province,southeast China[J].Science of the Total Environment,2006,368(2-3):531-541.
[42]Lin Y W,Liu T S,Guo H Y,et al.Relationships between Cd concentrations in different vegetables and those in arable soils,and food safety evaluation of vegetables in Taiwan[J].Soil Science and Plant Nutrition,2015,61(6):983-998.
[43]Liu W T,Zhou Q X,An J,et al.Variations in cadmium accumulation among Chinese cabbage cultivars and screening for Cd-safe cultivars[J].Journal of Hazardous Materials,2010,173(1-3):737-743.
[2]Song B,Lei M,Chen T B,et al.Assessing the health risk of heavy metals in vegetables to the general population in Beijing,China[J].Journal of Environmental Sciences,2009,21(12):1702-1709.
[3]Zhuang P,Mcbride M B,Xia H P,et al.Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine,South China[J].Science of the Total Environment,2009,407(5):1551-1561.
[4]Yang Q W,Xu Y,Liu S J,et al.Concentration and potential health risk of heavy metals in market vegetables in Chongqing,China[J].Ecotoxicology and Environmental Safety,2011,74(6):1664-1669.
[5]Yang L Q,Huang B,Hu W Y,et al.Assessment and source identification of trace metals in the soils of greenhouse vegetable production in eastern China[J].Ecotoxicology and Environmental Safety,2013,97:204-209.
[6]Xiao Q,Zong Y T,Lu S G.Assessment of heavy metal pollution and human health risk in urban soils of steel industrial city(Anshan),Liaoning,Northeast China[J].Ecotoxicology and Environmental Safety,2015,120:377-385.
[7]Hu J L,Wu F Y,Wu S C,et al.Phytoavailability and phytovariety codetermine the bioaccumulation risk of heavy metal from soils,focusing on Cd-contaminated vegetable farms around the Pearl River Delta,China[J].Ecotoxicology and Environmental Safety,2013,91:18-24.
[8]Alexander P D,Alloway B J,Dourado A M.Genotypic variations in the accumulation of Cd,Cu,Pb and Zn exhibited by six commonly grown vegetables[J].Environmental Pollution,2006,144(3):736-745.
[9]Li Q S,Cai S S,Mo C H,et al.Toxic effects of heavy metals and their accumulation in vegetables grown in a saline soil[J].Ecotoxicology and Environmental Safety,2010,73(1):84-88.
[10]Xu L,Lu X,Wang J H,et al.Accumulation status,sources and phytoavailability of metals in greenhouse vegetable production systems in Beijing,China[J].Ecotoxicology and Environmental Safety,2015,122:214-220.
[11]Lu J H,Yang X P,Meng X C,et al.Predicting cadmium safety thresholds in soils based on cadmium uptake by Chinese cabbage[J].Pedosphere,2017,27(3):475-481.
[12]Yang Y,Zhang F S,Li H F,et al.Accumulation of cadmium in the edible parts of six vegetable species grown in Cd-contaminated soils[J].Journal of Environmental Management,2009,90(2):1117-1122.
[13]Li X H,Zhou Q X,Wei S H,et al.Identification of cadmiumexcluding welsh onion(Allium fistulosum L.)cultivars and their mechanisms of low cadmium accumulation[J].Environmental Science and Pollution Research,2012,19(5):1773-1780.
[14]Shao T J,Pan L H,Chen Z Q,et al.Content of heavy metal in the dust of leisure squares and its health risk assessment-A case study of yanta district in Xi’an[J].International Journal of Environmental Research&Public Health,2018,(15):394-417.
[15]Chen X D,Lu X W,Li L Y,et al.Spatial distribution and contamination assessment of heavy metals in urban topsoil from inside the Xi’an second ringroad,NW China[J].Microchemical Journal,2013,(68):1979-1988.
[16]Chen H,Lu X W,Gao T N,et al.Identifying hot-spots of metal contamination in campus dust of Xi’an,China[J].International Journal of Environmental Research and Public Health,2016,(13):1-16.
[17]Lu X W,Zhang X L,Li L Y,et al.Assessment of metals pollution and health risk in dust from nursery schools in Xi’an,China[J].Environmental Research,2014,128:27-34.
[18]Chen Y P,Zheng Y J,Liu Q,et al.Atmospheric deposition exposes Qinling pandas to toxic pollutants[J].Ecological Applications,2017,(2):343-348.
[19]Deng W B,Li X X,An Z S,et al.Identification of sources of metal in the agricultural soils of the Guanzhong plain,northwest china[J].Environmental Toxicology and Chemistry,2017,(6):1510-1516.
[20]李雪芳,王文岩,上官宇先,等.西安市郊菜地土壤重金属污染及其与蔬菜重金属质量分数的相关性[J].西北农业学报,2014,23(8):173-181.Li X F,Wang W Y,Shangguan Y X,et al.Relationship of heavy metal pollution in soil and their mass fraction in vegetables in Xi’An city suburb[J].Acta Agriculturae Boreali-occidentalis Sinica,2014,23(8):173-181.
[21]李雪芳,王林权,尚浩博,等.小白菜和小青菜对镉、汞、砷的富集效应及影响因素[J].北方园艺,2014,(1):16-21.Li X F,Wang L Q,Shang H B,et al.The enrichment effect of Cd,Hg and As on brassica chinensis and Brassica pekinensis and its influencing factors[J].Northern Horticulture,2014,(1):16-21.
[22]Li X P,Feng L N,et al.Spatial distribution of hazardous elements in urban topsoils surrounding Xi’an industrial areas,(NW,China):Controlling factors and contamination assessments[J].Journal of Hazardous Materials,2010,174:662-669.
[23]Zhang H H,Chen J J,Zhu L,et al.Transfer of cadmium from soil to vegetable in the Pearl River Delta area,South China[J].PLoS One,2014,9(9):1-11.
[24]GB2762-2017,食品中污染物限量[S].GB2762-2017,Contaminant limit in food[S].
[25]Yang Y,Chen W P,Wang M E,et al.Regional accumulation characteristics of cadmium in vegetables:influencing factors,transfer model and indication of soil threshold content[J].Environmental Pollution,2016,219:1036-1043.
[26]Wang X P,Shan X Q,Zhang S Z,et al.A model for evaluation of the phytoavailability of trace elements to vegetables under the field conditions[J].Chemosphere,2004,55(6):811-822.
[27]Qiu Q,Wang Y T,Yang Z Y,et al.Responses of different Chinese flowering cabbage(Brassica parachinensis L.)cultivars to cadmium and lead exposure:screening for Cd+Pb pollution-safe cultivars[J].CLEAN-Soil Air Water,2011,39(11):925-932.
[28]Chen Y,Li T Q,Han X,et al.Cadmium accumulation in different pakchoi cultivars and screening for pollution-safe cultivars[J].Journal of Zhejiang University-Science B,2012,13(6):494-502.
[29]Wang X,Shi Y,Chen X,et al.Screening of Cd-safe genotypes of Chinese cabbage in field condition and Cd accumulation in relation to organic acids in two typical genotypes under long-term Cd stress[J].Environmental Science and Pollution Research,2015,(22):16590-16599.
[30]Girish C,Saifullah,Nanthi B,et al.Cellular mechanisms in higher plants governing tolerance to cadmium toxicity[J].Critical Reviewsin Plant Sciences,2014,33(5):374-391.
[31]Verbruggen N,Hermans C,Schat H.Mechanisms to cope with arsenic or cadmium excess in plants[J].Current Opinion in Plant Biology,2009,(12):364-372.
[32]Meng Y,Zhang L,Wang L Q,et al.Antioxidative enzymes activity and thiol metabolism in three leafy vegetables under Cd stress[J].Ecotoxicology and Environmental Safety,2019,173:214-224.
[33]Akhter F,McGarvey B,Macfie S M.Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors[J].Journal of Plant Physiology,2012,169(18):1821-1829.
[34]Mendoza-Cózatl D,Loza-Tavera H,Hernández-Navarro A,et al.Sulfur assimilation and glutathione metabolism under cadmium stress in yeast,protists and plants[J].FEMS Microbiology Reviews,2005,29(4):653-671.
[35]Souhir S,Alessandro F,Clarissa L,et al.Analysis of cadmium translocation,partitioning and tolerance in six barley(Hordeum vulgare L.)cultivars as a function of thiol metabolism[J].Biology and Fertility of Soils,2015,51(3):311-320.
[36]Negrin V L,Teixeira B,Godinho R M,et al.Phytochelatins and monothiols in salt marsh plants and their relation with metal tolerance[J].Marine Pollution Bulletin,2017,121(1-2):78-84.
[37]文典,胡霓红,赵凯,等.小白菜对土壤中5种重金属的富集特征及土壤安全临界值的研究[J].热带作物学报,2012,(11):1942-1948.Wen D,Hu N H,Zhao K,et al.Five kinds of heavy metals enrichment characteristics in Pakchoi(Brassica chinensis L.)and the critical values in the soil for Pakchoi production[J].Chinese Journal of Tropical Crops,2012,(11):1942-1948.
[38]赵勇,李红娟,孙治强.土壤、蔬菜Cd污染相关性分析与土壤污染阈限值研究[J].农业工程学报,2006,(7):149-153.Zhao Y,Li H J,Sun Z Q.Correlation analysis of Cd pollution in vegetables and soils and the soil pollution threshold[J].Transactions of the CSAE,2006,(7):149-153.
[39]Wang J L,Yuan J G,Yang Z Y,et al.Variation in cadmium accumulation among 30 cultivars and cadmium subcellular distribution in 2 selected cultivars of water spinach(Ipomoea aquatica Forsk.)[J].Journal of Agricultural and Food Chemistry,2009,57(19):8942-8949.
[40]Cui Y J,Zhu Y G,Zhai R H,et al.Transfer of metals from soil to vegetables in an area near a smelter in Nanning,China[J].Environment International,2004,30(6):785-791.
[41]Huang R Q,Gao S F,Wang W L,et al.Soil arsenic availability and the transfer of soil arsenic to crops in suburban areas in Fujian Province,southeast China[J].Science of the Total Environment,2006,368(2-3):531-541.
[42]Lin Y W,Liu T S,Guo H Y,et al.Relationships between Cd concentrations in different vegetables and those in arable soils,and food safety evaluation of vegetables in Taiwan[J].Soil Science and Plant Nutrition,2015,61(6):983-998.
[43]Liu W T,Zhou Q X,An J,et al.Variations in cadmium accumulation among Chinese cabbage cultivars and screening for Cd-safe cultivars[J].Journal of Hazardous Materials,2010,173(1-3):737-743.