三种植物对土壤磷吸收和富集能力的比较

筛选磷富集植物是磷矿废弃地土壤与植被修复的关键。该文以向日葵(Helianthus annuus)、苏丹草(Sorghum sudanense)、南瓜(Cucurbita moschata)为研究对象, 采用盆栽试验, 设置5个磷浓度(0、100、300、500和700 mg·kg^-1), 分别在3个不同生长时段(4周、7周、10周)内采样, 对这3种植物的磷吸收和富集能力进行了比较。结果表明: (1)在相同生长时间内, 向日葵、苏丹草、南瓜的地上部磷含量均随磷处理浓度的升高而增大, 最大值分别为9.67 g·kg^-1、4.86 g·kg^-1、6.32 g·kg^-1; 相同浓度下, 向日葵地上部磷含量随着生长时间的延长呈上升趋势, 苏丹草则呈下降趋势, 南瓜无显著变化; (2) 3种植物的地上部磷累积量均在磷处理浓度为700 mg·kg^-1时, 生长10周后达到最大值, 分别为217.83 mg·plant^-1、93.92 mg·plant^-1、135.82 mg·plant^-1; (3)各浓度处理下, 向日葵、苏丹草的地上部磷富集系数和转移系数均大于1.00, 南瓜的地上部磷富集系数和转移系数波动较大; 向日葵的富集系数和转移系数最大值分别达11.39和4.09。综合比较可知, 3种植物磷吸收和富集能力的大小顺序为: 向日葵>南瓜>苏丹草。向日葵各项富磷特征基本符合磷富集植物的筛选标准, 可作为磷矿废弃地土壤与植被修复的备选物种。     

基于小麦产品质量的土壤铅修复基准

近年来,污染土壤修复技术发展很快,而污染土壤修复标准的建立则相对迟缓。为了推进我国该领域的工作,利用盆栽实验,通过小麦生物量、小麦不同部位铅含量、土壤总铅含量及土壤有效态Pb含量的变化确定了棕壤土中Pb的土壤修复基准。结果表明:随着铅处理浓度的提高,小麦各器官中的铅含量逐渐升高,其中以根部含量最高,其次为茎叶、籽壳,籽实中铅的含量最低。以小麦籽实生物量降低10%为依据,确定棕壤中铅的土壤修复基准为292mg·kg^-1,有效铅含量为7mg·kg^-1。以小麦可食部位-籽实中铅含量的食品卫生标准为依据,确定棕壤中铅的土壤修复基准:总量为170mg·kg^-1,有效态含量为4mg·kg^-1。     

怀山药类原球茎的诱导形成与植株再生

为提高山药离体繁殖的速度, 缩短繁殖周期, 以铁棍山药(Dioscorea opposita cv. ‘Tiegun’)带腋芽茎段为材料, 对类原球茎的诱导、增殖、分化与植株再生进行了研究。结果表明, 铁棍山药类原球茎诱导的最适培养基为MS+1.0 mg·L^-1 TDZ+30 g·L^-1蔗糖, 增殖的最适培养基为MS+9 mg·L^-1 6-BA+30 g·L^-1蔗糖, 分化的最适培养基为MS+2 mg·L^-1 KT+0.02 mg·L^-1 NAA+30 g·L^-1蔗糖, 最适生根培养基为1/4MS+0.05 mg·L^-1 NAA+1.0 mg·L^-1 PP333+15 g·L^-1蔗糖, 生根率达80%, 移栽成活率可达85%。类原球茎的诱导形成及植株再生体系的建立为怀山药种苗的快速繁殖提供了一条新途径。     

以黄花乌头发根为外植体的再生培养体系建立

为获得黄花乌头(Aconitum coreanum)发根再生植株, 将其发根在添加0.5-5.0 mg·L^-1 6-BA及0-0.5 mg·L^-1 NAA的1/2MS固体培养基上进行光诱导培养, 发根经脱分化形成愈伤组织, 然后形成芽及芽丛, 最终获得发根再生植株。结果表明, 愈伤组织及不定芽分化的最适培养基为1/2MS+2.0 mg·L^-1 6-BA+0.2 mg·L^-1 NAA+3%蔗糖; 不定芽生根最适培养基为1/2MS+0.5 mg·L^-1 6-BA+0.1 mg·L^-1 NAA+5 mg·L^-1 GA+3%蔗糖。     

低磷胁迫下大麦叶片磷素利用特征

以大麦(Hordeum vulgare)磷高效基因型(DH110和DH147)和低效基因型(DH49)为材料, 采用盆栽实验研究大麦在极低磷(25 mg·kg^-1土)、低磷(50 mg·kg^-1土)和正常磷(75 mg·kg^-1土)处理下叶片的磷组分和酸性磷酸酶活性特征。结果表明, 低磷胁迫显著降低大麦叶片的无机磷含量, 但对难溶态磷含量影响较小。高效基因型上部叶核酸态磷含量显著高于低效基因型, 而下部叶则显著低于低效基因型, 是低效基因型的18.4%-91.4%。大麦下部叶酯磷含量和分配比例表现为高效基因型低于低效基因型, 而上部叶仅在低效基因型中显著低于高效基因型。核酸态磷和酯磷在高效基因型叶片中的含量分配表明其上部叶的磷素营养状况较优, 而下部叶易溶性有机磷的分解转化作用更强。低磷和极低磷胁迫下, 下部叶酸性磷酸酶的活性显著增加, 且高效基因型显著高于低效基因型, 分别为低效基因型的1.29-1.41倍。磷高效基因型大麦通过提高下部叶酸性磷酸酶活性加强酯磷和核酸态磷的分解, 转化为无机磷, 增加可移动性磷源的含量和比例, 以提高生育后期大麦的磷素再利用能力。     

海三棱藨草的组织培养与快繁体系

以海三棱藨草(Scirpus × mariqueter)成熟种子为外植体, 通过无菌萌发、丛生芽诱导、增殖、壮苗、生根和移栽等过程, 建立了海三棱藨草的无菌快繁体系。结果表明: 丛生芽诱导和增殖的最适培养基为MS+2.0 mg·L^-1 6-BA+0.002 mg·L^-1 TDZ+0.2 mg·L^-1 IBA; 壮苗最适培养基为1/2MS+0.05 mg·L^-1 6-BA+0.01 mg·L^-1 IBA; 生根最适培养基为1/2 MS+0.2 mg·L^-1 IBA; 最适培养温度为30°C; 再生苗移入珍珠岩:草炭:蛭石=1:1:1 (体积比)的混合基质中, 移栽成活率可达85%以上。生根培养阶段选用容积较大的塑料容器育苗, 可以降低生产成本和提高生产效率。     

粉美人萱草的快繁技术和大田种植

以粉美人萱草(Hemerocallis fulva cv. ‘Fenmeiren’)的花茎为外植体进行离体培养, 该研究成功建立了粉美人萱草组培快繁技术。结果表明, 6月获得的外植体用浓度为15% (v/v)的次氯酸钠溶液消毒8分钟, 外植体存活率达95%; 最佳增殖培养基为MS+1.0 mg·L^-1 6-BA+0.004 mg·L^-1 TDZ+0.1 mg·L^-1 NAA, 培养30天后, 月增殖系数达2.9; 壮苗培养基为MS+0.1 mg·L^-1 6-BA+0.1 mg·L^-1 IBA, 在该培养基中, 组培苗不再分化, 长势健壮; 最佳生根培养基为1/2MS+0.4 mg·L^-1 IBA+20 g·L^-1蔗糖, 生根率达95%; 移栽基质采用珍珠岩:草炭=1:2 (v/v), 通过精细化管理, 成活率可达85%, 出圃合格率为75%。目前已实现规模化繁殖, 并生产组培苗2.0×10⁵株, 大田种植表现良好。     

铜尾矿区土壤与凤丹植株重金属富集研究

对安徽铜陵铜尾矿区凤丹种植地的土壤和凤丹中重金属污染状况进行了研究.结果表明,尾矿库区种植地极端贫瘠,有机质含量仅1.1～3.4g·kg^-1,而土壤Cu、Cd、Pb、Zn含量皆高于对照土壤,其中Cu含量达587.43～1176.44mg·kg^-1,Cd含量达3.08～5.16mg·kg^-1,约达国家土壤二级标准的10倍.凤丹各部位的Cu、Cd和Pb含量均超过了药用植物的限量标准,尤其是根皮部位Cu含量达31.50～64.00mg·kg^-1,Cd含量达0.98～1.45mg·kg^-1,超出标准1.6～3.6倍,表明种植地和凤丹都受到严重污染.凤丹不同部位中的Zn、Cd、Pb和Cu分别以茎、叶、叶和根皮中的含量最高.凤丹对Cd、Zn的富集比Cu和Pb高,但在根皮中的富集系数均较小.     

铅胁迫对斜纹夜蛾生长发育与生殖的影响

在植食性昆虫斜纹夜蛾幼虫标准人工饲料中添加不同浓度的重金属铅（Pb）,研究Pb胁迫对其生长发育与生殖的影响.结果表明： 斜纹夜蛾不同发育阶段（幼虫、蛹和成虫）的存活率和体质量随着饲料中Pb浓度的增加而下降,引起存活率显著下降的最低Pb胁迫浓度是100 mg·kg^-1,引起体质量显著减少的最低Pb胁迫浓度是50 mg·kg^-1.在取食Pb浓度为25～200 mg·kg^-1的人工饲料后,斜纹夜蛾成虫的产卵天数显著减少;产卵力和生育力随着饲料中Pb浓度的增加而显著下降;1000粒卵的平均质量显著低于对照;卵孵化率显著下降.重金属Pb胁迫对斜纹夜蛾生长发育和生殖具有显著的抑制作用.     

两种杨树对高硼胁迫的生理响应

近年来国外学者发现杨树(Populus spp.)对硼表现出很强的富集能力和极强的耐受能力, 但其耐硼胁迫的生理机制和种间差异仍不清楚。该研究通过两年的硼梯度控制试验, 探讨了硼胁迫对欧洲黑杨杂交种俄罗斯杨(Populus russkii)和银白杨变种新疆杨(P. bolleca)的生长和生理指标的影响。结果表明, 新疆杨的耐高硼能力高于俄罗斯杨, 其高硼伤害阈值(EC10)为35 mg·kg^-1, 俄罗斯杨为19 mg·kg^-1。两种杨树的过氧化氢酶(CAT)和愈创木酚过氧化物酶(Gu-POD)活性随硼浓度升高而升高, 超过EC10后显著下降。尽管两种杨树的叶绿素含量和光化学效率在硼胁迫下降低, 但抗硼胁迫能力较强的新疆杨仍然保持了较高的叶绿素a/b值和热耗散能力(非光化学淬灭升高), 因此有效地保护了该树种的光合能力。两种杨树的可溶性糖含量随硼胁迫加重而适应性升高, 以维持其抗渗透能力, 但其叶片可溶性蛋白含量仅在中低强度的硼胁迫条件下有所升高。该研究明确了两个富集硼的杨树种对高硼胁迫的生理响应及其种间差异。     

Differences on Pb accumulation among plant tissues of 25 varieties of maize (Zea mays)

Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years.Heavy metal pollutants may enter the human food chain through agricultural products and groundwater from the polluted soils.Progress has been made in the past decade on phytoremediation,a safe and inexpensive approach to remove contaminants from soil and water using plants.However,in most cases,agricultural land in China cannot afford to grow phytoremediator plants instead of growing crops due to food supply for the great population.Therefore,new and effective methods to decrease the risk of heavy metal pollution in crops and to clean the contaminated soils are urgently needed.If we can find crop germplasms (including species and varieties) that accumulate heavy metals in their edible parts,such as the leaves of vegetables or grains of cereals,at a level low enough for safe consumption,then we can grow these selected species or varieties in the lands contaminated or potentially contaminated by heavy metals.If we can find crop germplasms that take in low concentrations of heavy metals in their edible parts and high content of the metals in their inedible parts,then we can use these selected species or varieties for soil remediation.In this study,the feasibility of the method is assessed by analyzing Pb concentrations in edible and inedible parts of 25 varieties of maize (Zea mays) grown in Pb-contaminated soils.The soil concentrations of Pb were 595.55 mg/kg in the high Pb exposed treatment and 195.55 mg/kg in the control.The results showed that the Pb concentrations in different tissues were in the order of root ＞ shoot ≌ leaf＞ grain.Compared with the control,the Pb concentrations in root,shoot and leaf were greatly increased under the high Pb exposed condition,while the increments of Pb concentration in grain were relatively lower.Under the high Pb exposure,the grain Pb concentrations of 12 varieties exceeded the maximal Pb limitation of the National Food Hygiene Standard of China (NFHSC) and were inedible.This indicates that there is a high Pb pollution risk for maize grown on Pb polluted sites.Although 22 of the 25 tested varieties had harvest loss under the highly Pb stressed condition,ranging from 0.86%-38.7% of the grain biomass acquired at the control,the average harvest loss of all the tested varieties was only 12.6%,which is usually imperceptible in normal farming practices.Therefore the risk of Pb pollution in maize products cannot be promptly noticed and prevented based only on the outcome of the harvest.However,we did find that 13 of the 25 tested varieties had grain Pb concentrations lower than the limitation of the NFHSC.It is,therefore,possible to reduce the pollution risk if these favorable varieties are used for maize production in Pb-contaminated or potentially contaminated agricultural lands.Pb concentrations in vegetative tissues (root,stem and leaf) were significantly correlated with each other,while Pb concentrations of each vegetative tissue were not significantly correlated with that of grain.Among the 25 tested varieties,some varieties had Pb concentrations in grain lower than (No.1-3 and No.6) or slightly above (No.4) the limitation of the NFHSC,while their Pb concentrations in the vegetative tissues were among the highest.When excluding these varieties,correlations between the Pb concentrations of grain and those of vegetative tissues of the rest of the tested varieties became highly significant.In addition,variety No.1 had the lowest harvest loss under high Pb exposed,and the highest Pb accumulation in vegetative tissues (51.69 mg/plant,12 times as much as in the control).Similar features were also observed in varieties No.2,No.3 and No.6,which absorbed Pb for 36-42 mg/plant under high Pb exposed.We recommend these varieties of maize to be used for bioremediation of Pb contaminated soil and crop production at the same time.     

Differences on Pb accumulation among plant tissues of 25 varieties of maize ( Zea mays )

Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years. Heavy metal pollutants may enter the human food chain through agricultural products and groundwater from the polluted soils. Progress has been made in the past decade on phytoremediation, a safe and inexpensive approach to remove contaminants from soil and water using plants. However, in most cases, agricultural land in China cannot afford to grow phytoremediator plants instead of growing crops due to food supply for the great population. Therefore, new and effective methods to decrease the risk of heavy metal pollution in crops and to clean the contaminated soils are urgently needed. If we can find crop germplasms (including species and varieties) that accumulate heavy metals in their edible parts, such as the leaves of vegetables or grains of cereals, at a level low enough for safe consumption, then we can grow these selected species or varieties in the lands contaminated or potentially contaminated by heavy metals. If we can find crop germplasms that take in low concentrations of heavy metals in their edible parts and high content of the metals in their inedible parts, then we can use these selected species or varieties for soil remediation. In this study, the feasibility of the method is assessed by analyzing Pb concentrations in edible and inedible parts of 25 varieties of maize (Zea mays) grown in Pb-contaminated soils. The soil concentrations of Pb were 595.55 mg/kg in the high Pb exposed treatment and 195.55 mg/kg in the control. The results showed that the Pb concentrations in different tissues were in the order of root > shoot ≅ leaf > grain. Compared with the control, the Pb concentrations in root, shoot and leaf were greatly increased under the high Pb exposed condition, while the increments of Pb concentration in grain were relatively lower. Under the high Pb exposure, the grain Pb concentrations of 12 varieties exceeded the maximal Pb limitation of the National Food Hygiene Standard of China (NFHSC) and were inedible. This indicates that there is a high Pb pollution risk for maize grown on Pb polluted sites. Although 22 of the 25 tested varieties had harvest loss under the highly Pb stressed condition, ranging from 0.86%–38.7% of the grain biomass acquired at the control, the average harvest loss of all the tested varieties was only 12.6%, which is usually imperceptible in normal farming practices. Therefore the risk of Pb pollution in maize products cannot be promptly noticed and prevented based only on the outcome of the harvest. However, we did find that 13 of the 25 tested varieties had grain Pb concentrations lower than the limitation of the NFHSC. It is, therefore, possible to reduce the pollution risk if these favorable varieties are used for maize production in Pb-contaminated or potentially contaminated agricultural lands. Pb concentrations in vegetative tissues (root, stem and leaf) were significantly correlated with each other, while Pb concentrations of each vegetative tissue were not significantly correlated with that of grain. Among the 25 tested varieties, some varieties had Pb concentrations in grain lower than (No.1–3 and No.6) or slightly above (No.4) the limitation of the NFHSC, while their Pb concentrations in the vegetative tissues were among the highest. When excluding these varieties, correlations between the Pb concentrations of grain and those of vegetative tissues of the rest of the tested varieties became highly significant. In addition, variety No. 1 had the lowest harvest loss under high Pb exposed, and the highest Pb accumulation in vegetative tissues (51.69 mg/plant, 12 times as much as in the control). Similar features were also observed in varieties No.3, No.3 and No.6, which absorbed Pb for 36–42 mg/plant under high Pb exposed. We recommend these varieties of maize to be used for bioremediation of Pb contaminated soil and crop production at the same time. Translated from Acta Phytoecologica Sina, 2006, 29(6): 992–999 [译自: 植物生态学报]     

氮磷水平和播期对春小麦籽粒灌浆期降落数值动态变化的影响

利用不同品质类型春小麦(Triticum aestivum)品种在大田条件下研究了灌浆期籽粒降落数值动态变化规律以及氮磷肥与播期的影响效应。结果表明,开花15 d至成熟期间,籽粒降落数值呈先升后降的单峰曲线变化,并推知α_淀粉酶活性(液化值)呈先降后升的单谷曲线变化。在富钾情况下,氮素增施,高蛋白强筋品种降落数值增加,动态曲线峰值上升且出现时间推迟,而高蛋白中筋和低蛋白弱筋品种降落数值则降低,峰值下降且出现时间提前。磷素增施,各基因型品种降落数值均降低;动态曲线峰值、谷值及出现时间因基因型呈不同变化。氮磷(钾)素平衡配施是形成较高降落数值(较低α_淀粉酶活性)的关键。在无水分胁迫情况下,光温互作是影响各基因型籽粒降落数值动态形成的首要条件,其次为降水;且在光温因子互作中,光合有效辐射为最敏感因子。较高的光温条件互作是形成各品种较高降落数值的基础,在此基础上增加光合有效辐射则使高蛋白强筋品种降落数值增加;而以此为基础,在一定水平光照条件限度内,增加光合有效辐射则使高蛋白中筋和低蛋白弱筋品种降落数值增加,超过限度则使其降低。气象条件的影响作用及基因型差异可通过曲线动态变化反映出来。不同基因型降落数值在不同环境条件(氮磷肥水平和气象条件)下变异不同。     

胡杨根际细菌提高木本植物对重金属胁迫的耐受性

胡杨是我国西北荒漠地区特有的、对多种非生物逆境具有高抗逆性的树种,但其相关微生物的生态和生理功能研究还比较缺乏.本文从新疆沙雅地区原始胡杨林根际土壤中分离出重金属抗性细菌共72株.其中具有单一重金属(Cu²⁺、Ni²⁺、Pb²⁺或Zn²⁺)抗性的细菌菌株50株,有三重以上重金属抗性的菌株9株.将其中5株多重重金属抗性细菌接种至生根的竹柳插条,进行重金属胁迫下的盆栽培养.结果表明: 在铜或锌胁迫下,5株多重重金属抗性细菌对竹柳的生长抑制有不同程度的缓解,其中假单胞菌Z30和贪铜菌N8菌对铜和锌两种胁迫下竹柳生物量的增长与不接菌对照相比均达到显著差异水平.说明在非重金属污染区生长的胡杨根际存在多样性的重金属抗性细菌,其中一些多重重金属抗性菌对改善重金属胁迫下植物的生长有显著作用,具有应用于木本植物-微生物联合修复环境重金属污染的价值.     

微生物对植物修复重金属污染土壤的促进效果

以印度芥菜作为超富集植物,通过盆栽试验研究了巨大芽胞杆菌和胶质芽胞杆菌的混合微生物制剂、黑曲霉30177发酵液对植物修复Cd、Pb、Zn污染土壤的作用.结果表明：巨大芽胞杆菌和胶质芽胞杆菌的混合微生物制剂不仅可以促进超富集植物的生长,增强超富集植物对土壤Cd、Pb、Zn的吸收,而且大幅度提高了植物的修复效率,在添加外源可溶性Cd、Pb、Zn的污染土壤上,可分别使印度芥菜提取量(以植物干质量计)提高1.18、1.54和0.85倍,在添加底泥Cd、Pb、Zn污染的土壤上,可分别使印度芥菜提取量提高4.00、0.64和0.65倍,在底泥污染的土壤上的促进效果明显强于外源添加污染的土壤.黑曲霉30177发酵液能显著促进印度芥菜对土壤Cd、Pb、Zn的吸收,在添加外源可溶性Cd、Pb、Zn的污染土壤上,印度芥菜地上部Cd、Pb、Zn的吸收量分别比对照提高了88.82%、129.04%和16.80%;在添加底泥Cd、Pb、Zn污染的土壤上,可分别比对照提高78.95%、113.63%和33.85%;但它可导致印度芥菜生物量的大幅度降低,起不到提高植物修复提取量的效果.经反相高效液相色谱初步分析发现,胶质芽胞杆菌、巨大芽胞杆菌发酵液中含有草酸、柠檬酸等有机酸,有机酸对重金属有一定的溶解作用,从而提高了重金属的生物有效性.     

Effect of simultaneous establishment of Sedum alfredii and Zea mays on heavy metal accumulation in plants

Land application of biosolids to improve agricultural productivity is a cost-effective approach for resource recovery. Unfortunately, municipal biosolids often contain high concentrations of heavy metals, including zinc and copper. In this study, a co-cropping technique was investigated using a known zinc hyperaccumulator, Sedum alfredii with a grain crop, Zea mays. After a 3-mo growth trial, the results indicate that when Z. mays is co-cropped with S. alfredii, heavy metals accumulated in the grains were significantly reduced when compared to monoculture cropping. Co-cropping improved the growth of both plant species. In addition, the biosolids maintained stable pH, N-P-K concentrations, germination potential, and water content after the plant treatment, regardless of the plant species used in the trial. In conclusion, co-cropping with hyperaccumulators may be an effective approach to reducing the risk of contaminant uptake in edible crops.     

EFFECTS OF INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI ON MAIZE GROWN IN MULTI-METAL CONTAMINATED SOILS

Pot culture experiments were established to determine the effects of colonization by arbuscular mycorrhizal fungi (AMF) (Glomus mosseae and G. sp) on maize (Zea mays L.) grown in Pb, Zn, and Cd complex contaminated soils. AMF and non-AMF inoculated maize were grown in sterilized substrates and subjected to different soil heavy metal (Pb, Zn, Cd) concentrations. The root and shoot biomasses of inoculated maize were significantly higher than those of non-inoculated maize. Pb, Zn, and Cd concentrations in roots were significantly higher than those in shoots in both the inoculated and non-inoculated maize, indicating the heavy metals mostly accumulated in the roots of maize. The translocation rates of Pb, Zn, and Cd from roots to shoots were not significantly difference between inoculated and non-inoculated maize. However, at high soil heavy metal concentrations, Pb, Zn, and Cd in the shoots and Pb in the roots of inoculated maize were significantly reduced by about 50% compared to the non-inoculated maize. These results indicated that AMF could promote maize growth and decrease the uptake of these heavy metals at higher soil concentrations, thus protecting their hosts from the toxicity of heavy metals in Pb, Zn, and Cd complex contaminated soils.     

不同品种小白菜对镉的吸收积累差异

通过盆栽试验,研究了60个小白菜品种在不同程度镉污染土壤中吸收和积累镉能力的差异.结果表明：在土壤镉浓度为0.6 mg·kg^-1时,小白菜镉含量超过国家标准的为8.33％;而在土壤镉浓度为1.2 mg·kg^-1时其超标率达66.67%,表明小白菜容易受到镉污染.2种镉浓度下白菜地上部分镉含量均低于国家食用标准,且其生物量不受影响的小白菜品种为：长梗白菜、上海青、矮箕苏州青、青优四号、矮脚葵翩黑叶白菜、皱叶黑油冬儿、高华青梗白菜、早生华京、金冠清江白、夏王青梗菜、利丰青梗白菜和杭州油冬儿.这12个品种可作为在镉轻度污染土壤中种植的安全系数较高的小白菜品种.     

Ecological risk and contamination history of heavy metals in the Andong tidal flat,Hangzhou Bay,China

In this study, we collected two sediment cores (C1 and C2) from the Andong tidal flat, Hangzhou Bay, and studied the temporal variations of heavy metals in the cores. Vertical distributions of heavy metals were almost unchanged in both the cores before 2000. After 2000, however, the heavy metal concentrations increased dramatically, suggesting that the sediments have been affected by enhanced human pollution in the recent decade. In the core C1, the sediments were severely polluted by Pb, moderately to considerably polluted by Cr and Zn, and low to moderately polluted by other heavy metals. The core C2 was relatively unpolluted before 2000 and low to moderately polluted after 2000. Multi-statistical analyses indicated that the core C1 was additionally contaminated by local human activities such as wastewater discharge and the Hangzhou Bay Bridge. The heavy metals in the core C2, however, were largely contributed by the Yangtze River and controlled by sedimentation process. The calculated sedimentary flux (4–8 g m^?2 a^?1) of heavy metals generally increased with time. It was closely related to the wastewater discharge in adjacent areas. This study reconstructed the local heavy metal pollution history and provides important information for environmental protection and policy making.     

重金属污染土壤原位钝化修复研究进展

重金属原位钝化技术是一种污染土壤的修复方法,指向污染土壤添加一些活性物质（钝化修复剂）,以降低重金属在土壤中的有效浓度或改变其氧化还原状态,从而有效降低其迁移性、毒性及生物有效性.本文基于原位钝化修复剂种类、研究方法、评价指标、作用机制以及风险评价等方面的研究,深入分析了该领域的研究现状和存在问题,并提出了今后研究的重点.目前广泛使用的钝化修复剂主要有粘土矿物、磷酸盐、有机堆肥及微生物材料等.由于土壤结构和组分的复杂性,钝化修复剂的作用机制尚不完全清楚,其可能的机制主要包括沉淀反应、化学吸附与离子交换、表面沉淀、有机络合和氧化还原等.今后应加强从分子水平研究重金属的钝化机制,重点关注钝化修复重金属污染土壤时存在的潜在风险以及钝化修复的长期田间效应.