紫色土Zn,Cd复合污染生态效应研究

通过盆栽生物试验结合野外典型污染调查 ,研究紫色土Zn、Cd复合污染对莴笋、蕃茄、甘兰、小麦等的作物效应 .结果表明 ,Zn、Cd复合污染对Zn表现为加和作用 ,低浓度Cd促进Zn吸收 ,加重Zn对养分吸收的抑制 ,加剧Zn的毒害作用 ;复合效应对Cd表现为竞争作用 ,高浓度Zn抑制Cd吸收 ,减轻Cd对养分吸收的抑制 ,缓解Cd毒性 ,向土壤添加Zn 50 0mg·kg- 1 为供试盆栽条件下拮抗效应的临界值 .     

绿洲土Cd、Pb、Zn、Ni复合污染下重金属的形态特征和生物有效性

通过模拟基于干旱区绿洲土壤Cd-Pb-Zn-Ni复合污染下的油菜盆栽试验,采用Tessier五步连续浸提法探究了重金属复合污染对油菜生长的影响及其各形态的转化归趋和生物有效性.结果显示,随着Cd-Pb-Zn-Ni复合胁迫水平的升高,油菜的干重先增加后减小,根系的生长由促进作用转变为抑制作用;对照土壤中4种重金属元素均以残渣态为主要赋存形态,可交换态的含量均很小;随着外源重金属的添加,油菜种植土壤中4种重金属元素的各形态含量随之增加,Cd、Pb、Zn的可交换态和Ni的碳酸盐结合态对外界胁迫响应强度最大,Cd、Pb、Zn、Ni的活性增加,且Cd、Pb的主要赋存形态迅速转变为碳酸盐结合态和铁锰氧化态,Zn的主要赋存形态由残渣态和碳酸盐结合态过渡到碳酸盐结合态和铁锰氧化态,Ni的主要赋存形态为碳酸盐结合态;Cd、Zn在茎叶中的含量大于根系,Pb、Ni反之,油菜能将Cd、Zn更多的运输至茎叶,Pb、Ni则主要积累在根系;油菜茎叶吸收Cd和油菜各部位吸收Zn的主要贡献形态为可交换态,根吸收Cd的主要贡献形态由可交换态转变为有机结合态,根吸收Pb和油菜各部位吸收Ni的主要贡献形态为碳酸盐结合态.     

镉与锌复合污染对栝楼幼苗生理特性的影响

通过室内盆栽实验,研究镉(Cd)、锌(Zn)复合污染对栝楼(Trichosanthes kirilowii Maxim.)幼苗生理特性的影响.结果显示,随着Cd、Zn浓度的升高,叶绿素a、叶绿素b、总叶绿素、可溶性糖及紫外吸收物含量下降;超氧化物歧化酶(SOD)活性先升高再下降,过氧化物酶(POD)活性及类胡萝卜素含量呈升—降—升趋势;丙二醛(MDA)和可溶性蛋白含量分别呈S"型及倒N"型曲线变化.与对照相比,在不同浓度复合污染条件下,光合色素、可溶性糖、可溶性蛋白、紫外吸收物含量及SOD活性均有所下降,POD活性和MDA含量上升.研究表明,栝楼幼苗对Cd、Zn胁迫具有一定的耐受力,但高浓度Cd、Zn对幼苗正常生长有较为显著的抑制作用.     

刺楸年轮中重金属含量动态变化及富集特性

为探索刺楸对受污染土壤重金属的富集和修复效应, 以南京栖霞山的乡土树种刺楸及其根际周边土壤为研究对象, 截取其根基部年轮盘及根际土壤样本, 采用ICP-AES法测定年轮及土壤样本中重金属(Cu、Cd、Cr、Mn、Ni、Pb、Zn)元素含量。结果表明: 栖霞山样地中的土壤受Mn、Pb和Zn污染最为严重, 存在Cu、Cd、Mn、Pb、Zn元素的高度复合污染, Cd、Cr、Cu、Ni、Zn在土壤和年轮中存在相关性, Mn和Pb则没有表现出明显的相关性; 刺楸修复受Cd、Mn、Pb、Zn污染的土壤效果并不显著, 更适用于Cr、Cu、Ni污染的土壤修复; 鉴于Cu元素含量变化特征, 刺楸也可以作为反映当地污染历史的记录载体; 刺楸年轮中的重金属元素之间存在交互作用, 其中Cd与Zn元素含量高度相关(r=0.984, p<0.01), 在刺楸年轮吸收重金属元素的过程中, Cu与Cd、Cr、Mn、Zn元素具有协同作用, Mn元素对其他元素有一定的拮抗作用。     

石灰配施猪粪对Cd、Pb和Zn污染土壤中重金属形态和植物有效性的影响

通过盆栽试验,研究在镉、铅和锌污染土壤上,石灰和猪粪配施对土壤中不同形态镉、铅和锌含量及在蔬菜中累积的影响.结果表明:施入石灰(L)、石灰加低量猪粪(LP1)、石灰加高量猪粪(LP2)后,土壤中碳酸盐结合态Cd、Pb和Zn含量明显降低,土壤中铁、锰氧化物结合态和有机物结合态Cd、Pb和Zn含量明显增加;对大白菜吸收Pb、Cd和Zn均起到较好的抑制作用.单施石灰处理,石灰用量为5 g·kg-1土时,对大白菜吸收Pb、Cd和Zn的抑制效果最好;石灰配施猪粪处理,其中石灰5 g·kg-1土配施猪粪7.5 g·kg-1土以及石灰5 g·kg-1土配施猪粪15 g·kg-1土对大白菜吸收Pb、Cd和Zn的抑制效果最好.研究同时发现,低量猪粪配施石灰的效果强于高量猪粪配施石灰的效果.     

Zn、Cd及其复合对小麦幼苗吸收Ca、Fe、Mn的影响

研究了溶液培养条件下Cd、Zn及其复合对小麦幼苗吸收Ca、Fe、Mn的影响.结果表明,小麦幼苗对Zn、Cd的吸收随溶液中Cd²⁺、Zn²⁺浓度的升高而增加,Cd、Zn同时存在时与其单独作用时幼苗对它们的吸收不同,Zn影响幼苗对Cd的吸收,Cd对Zn的吸收起抑制作用.Ca、Mn的吸收随溶液中Cd²⁺、Zn²⁺浓度升高而呈下降趋势,在Cd单独处理组和Zn单独处理组中Fe的吸收随Cd²⁺、Zn²⁺浓度升高而增加,但在Zn+Cd处理组中,Fe的吸收则呈下降趋势,其效应方式还与作物具体部位有关.     

佳乐麝香和镉复合污染对土壤中细菌和真菌数量的影响

在实验室模拟条件下,研究佳乐麝香(HHCB)和Cd单一、复合污染对培养10周土壤中细菌和真菌数量的影响。结果表明:HHCB和Cd单一、复合污染对土壤细菌(单一Cd除外)和真菌数量均有显著影响(P0.01),500、1000 mg·kg-1的HHCB和10 mg·kg-1Cd单一、复合污染对土壤细菌数量影响先抑制后促进,100、500 mg·kg-1的HHCB和10 mg·kg-1Cd单一、复合污染对真菌生长有促进作用。随着HHCB浓度的增加,第5~10周,土壤细菌抑制率减少;第1~10周,土壤真菌抑制率增加(单一HHCB污染第1、4和6周以及复合污染第4和10周除外)。复合污染对细菌联合效应在第1周表现为协同作用,对真菌联合效应在第7~8周表现为拮抗作用。     

东南景天对锌、镉复合污染的反应及其对锌、镉的吸收和积累特性

东南景天(Sedum alfredii Hance)已被鉴定为一种中国原生的新的锌超积累植物。 本文主要研究了锌(Zn)、镉(Cd)复合处理水平对东南景天的生长及其对锌、镉的吸收积累特性的影响。 结果表明,在Zn/Cd复合水平为500/100 祄ol/L时,植物生长最佳。Zn/Cd在东南景天叶片、茎部和根系中含量随着Zn/Cd处理水平的提高而增高。在Zn/Cd 复合水平为50/400 祄ol/L时茎叶中Cd含量达最高,其中叶片Cd含量达12.1 g/kg;在Zn/Cd 复合水平为1 000/50 祄ol/L时茎叶中Zn含量达最高, 其中茎中Zn含量达 23.2 g/kg。 植株各部位Cd含量的分布为:叶片>茎>>根系,而Zn在体内的分布为: 茎>叶片>>根系。 Zn、Cd在地上部和根部的积累量也随着处理水平的提高而增加,分别在Zn/Cd复合水平为250/400和500/100 祄ol/L下达高峰值。 东南景天地上部积累最高Zn和Cd的量分别达11和5 g/plant, 其比根系的积累量分别大10和25余倍。 Zn、Cd对东南景天的生长、吸收积累的相互作用依赖于Zn/Cd复合水平和植物部位。 在适宜Zn/Cd 处理水平范围内,Zn和Cd的吸收和积累具有相互促进作用。 高Zn或高Cd处理均抑制了植物对Zn和Cd的吸收和积累。 本研究结果表明,东南景天不仅具有忍耐高Zn/Cd复合污染,而且具有超量积累Zn和Cd的特异能力。 它为进一步研究植物Zn、Cd     

两种钝化剂对污染土壤上生菜吸收重金属和养分的影响

为明确分子筛、硅灰石作为钝化剂修复粤北Cd污染农田土壤的效果,采用盆栽生菜(Lactuca sativa)试验,评估钝化剂应用潜力和对作物营养元素吸收可能的负面效应。结果表明,高剂量(≥660 mg Si/kg)分子筛和硅灰石分别降低了土壤Cd和Pb的有效性,而低剂量(220 mg Si/kg)反而使土壤Cd和Pb有效性上升,添加≥660 mg Si/kg的钝化剂使生菜对Cd和Pb积累具有显著抑制效应。硅灰石通过显著提高土壤有效Ca,增强Ca-Cd竞争吸收来抑制生菜Cd累积,而非通过降低土壤Cd有效性起作用。施用分子筛会降低生菜的Ca、Mg、Mn和Zn含量,小幅增加Cu含量。施用硅灰石则降低生菜的Mn、Zn含量,小幅增加Ca、Cu含量。高剂量(880 mg Si/kg)的分子筛会使生菜产量降低29%,而添加≥660 mg Si/kg硅灰石可使产量提高10%～12%。因此,硅灰石具增产抑Cd效能,在大面积Cd污染土壤的修复中有应用前景,但需适度补充Zn、Mn养分。     

重金属复合污染对小麦种子根活力的影响

应用二次回归旋转设计法,以小麦种子为材料,研究了水培条件下重金属复合污染对其根生长及活力的影响;借助回归分析建立了相应的数学模型,分析了Cu、Zn、Cd和Pb4种重金属对根活力的毒性、两两重金属问的联合作用以及各重金属的边际毒性效应．结果表明重金属对根活力的影响顺序为Pb＞Cu＞Cd＞Zn;Cu与Cd、Cu与Zn、Zn与Cd以及Cd与Pb元素间的互作效应显著;在0-20mg.L^-1浓度范围内,Cu和zn两元素在最小浓度时的边际效应值最大,Cd和Pb两元素的边际效应最大值却出现在最高浓度处．     

重金属Cd－Zn对水稻的复合污染和生态效应

重金属Ｃｄ－Ｚｎ对水稻的复合污染和生态效应周启星（浙江农业大学,杭州３１００２９）吴燕玉,熊先哲（中国科学院沈阳应用生态研究所,１１００１５）ＣｏｍｐｏｕｎｄｐｏｌｌｕｔｉｏｎｏｆＣｄａｎｄＺｎａｎｄｉｔｓｅｃｏｌｏｇｉｃａｌｅｆｆｅｃｔｏｎｒｉｃｅ...     

Zn pollution counteracts Cd toxicity in metal-tolerant ectomycorrhizal fungi and their host plant, Pinus sylvestris

Adaptive Zn and Cd tolerance have evolved in populations of the ectomycorrhizal fungus Suillus luteus. When exposed to high concentrations of both metals in vitro, a one-sided antagonism was apparent in the Zn- and Cd-tolerant isolates. Addition of high Zn concentrations restored growth of Cd-stressed isolates, but not vice versa. The antagonistic effect was not detected in a S. luteus isolate from non-contaminated land and in Paxillus involutus. The fungi were inoculated on pine seedlings and subsequently exposed to ecologically relevant Zn and Cd concentrations in single and mixed treatments. The applied doses severely reduced nutrient acquisition of non-mycorrhizal pines and pines inoculated with metal-sensitive S. luteus. Highest translocation of Zn and Cd to shoots occurred in the same plants. Seedlings inoculated with fungi collected from the polluted site reduced metal transfer to their host and maintained nutrient acquisition under high metal exposure. The isolate showing highest tolerance in vitro also offered best protection in symbiosis. The antagonistic effect of high Zn on Cd toxicity was confirmed in the plant experiment. The results indicate that a Zn- and Cd-polluted soil has selected ectomycorrhizal fungi that are able to survive and protect their phytobiont from nutrient starvation and excessive metal uptake.     

Cd、Zn及其交互作用对互花米草中重金属的积累、亚细胞分布及化学形态的影响

通过盆栽试验,研究了Cd、Zn及其交互作用下互花米草中Cd、Zn的含量及积累量,并分析了Cd、Zn在互花米草中的亚细胞分布及化学形态。结果表明：Cd-Zn处理组互花米草地上部及根部Cd含量显著高于Cd处理组;Cd-Zn处理组根部Zn含量显著低于Zn处理组,但地上部差异不显著,说明Zn促进Cd的吸收,Cd抑制Zn的吸收。Cd-Zn处理组互花米草地上部Cd积累量显著高于Cd处理组,但是根部Cd积累量却显著低于Cd处理组;Zn处理组地上部及根部Zn积累量均显著高于对照组及Cd-Zn处理组。Cd单因素胁迫下,Cd主要分布在细胞壁,Cd-Zn交互作用下,Cd在胞液中的分配比例高于其他细胞组分;Zn单因素及Cd-Zn交互作用下,Zn在胞液中的分配比例均较高,总的分配比例呈现以下趋势：胞液>细胞壁>细胞器,说明Zn的添加影响了Cd的亚细胞分布,Cd的出现对Zn在互花米草细胞中的分布影响不明显。Cd和Zn在互花米草叶中主要以氯化钠提取态存在,表明互花米草中Cd和Zn多以果胶酸盐结合态或蛋白质结合态存在。     

Soil-applied zinc and copper suppress cadmium uptake and improve the performance of cereals and legumes

The present study aimed to evaluate the effect of soil-applied Zn and Cu on absorption and accumulation of Cd applied through irrigation water in legume (chickpea and mung bean) and cereal (wheat and maize) crops. The results revealed that Cd in irrigation water at higher levels (2 and 5 mg L^?1) significantly (p < 0.05) reduced the plant biomass while the soil application of Zn and Cu, singly or combined, favored the biomass production. Plant tissue Cd concentration increased linearly with the increasing application of Cd via irrigation water. While Cd application caused a redistribution of metals in grains, straw, and roots with the highest concentration of Cd, Zn, and Cu occurred in roots followed by straw and grains. Zinc addition to soil alleviated Cd toxicity by decreasing Cd concentration in plant tissues due to a possible antagonistic effect. The addition of Cu to the soil had no consistent effects on Zn and Cd contents across all crops. Inhibitory effects of Cd on the uptake and accumulation of Zn and Cu have also been observed at higher Cd load. Thus, soil-applied Zn and Cu antagonized Cd helping the plant to cope with its toxicity and suppressed the toxic effects of Cd in plant tissues, thus favoring plant growth.     

The Effects of Cadmium-Zinc Interactions on Biochemical Responses in Tobacco Seedlings and Adult Plants

The objective of the present study was to investigate the effects of cadmium-zinc (Cd-Zn) interactions on their uptake, oxidative damage of cell macromolecules (lipids, proteins, DNA) and activities of antioxidative enzymes in tobacco seedlings as well as roots and leaves of adult plants. Seedlings and plants were exposed to Cd (10 µM and 15 µM) and Zn (25 µM and 50 µM) as well as their combinations (10 µM or 15 µM Cd with either 25 µM or 50 µM Zn). Measurement of metal accumulation exhibited that Zn had mostly positive effect on Cd uptake in roots and seedlings, while Cd had antagonistic effect on Zn uptake in leaves and roots. According to examined oxidative stress parameters, in seedlings and roots individual Cd treatments induced oxidative damage, which was less prominent in combined treatments, indicating that the presence of Zn alleviates oxidative stress. However, DNA damage found in seedlings, and lower glutathione reductase (GR) and superoxide dismutase (SOD) activity recorded in both seedlings and roots, after individual Zn treatments, indicate that Zn accumulation could impose toxic effects. In leaves, oxidative stress was found after exposure to Cd either alone or in combination with Zn, thus implying that in this tissue Zn did not have alleviating effects. In conclusion, results obtained in different tobacco tissues suggest tissue-dependent Cd-Zn interactions, which resulted in activation of different mechanisms involved in the protection against metal stress.     

Effect of Cd,Zn, and Pb Compound Pollution on Celery in a Ferric Acrisol

A pot experiment with an orthogonal experimental design L₉(3⁴) was conducted to study the combined effects of Cd, Zn, and Pb on the growth and metal content of celery grown in a ferric acrisol. The uptake of Cd, Zn, and Pb by celery was not only affected by the individual elements, but also by combinations of the elements. The effect of coexisting elements on plant uptake of the heavy metals depended on the concentration ratios of the elements. There is a given ratio where a maximum antagonism or synergism effect occurs. The combinations of elements clearly affected the dry weight of celery and the heavy metal concentration in celery. The removal rate (the ratio of plant total uptake to the total metal content in soil) was in the order of Cd > Zn > Pb, with no obvious difference between the removal rate under single pollution and that under compound pollution.     

Characterization of a cadmium-zinc complex in lettuce leaves

Vegetable food contributes a higher amount of daily cadmium (Cd) intake in humans than food of animal origin. The bioavailability of plant Cd depends on the content of plant zinc (Zn). The mechanism by which increased plant Zn lowers the intestinal absorption of plant Cd could be mediated by changes in the chemical speciation of Cd or Zn in plant edible tissues, including Zn-induced phytochelatin synthesis. To test this hypothesis we investigated the chemical speciation of Cd and Zn in leaf extracts of lettuce grown under 10 ΜM of Cd accompanied by 0.32 or 31.6 ΜM Zn in nutrient solution. Gel filtration chromatography of the low- or high-Zn leaf extracts yielded a major low molecular weight Cd-Zn complex that eluted at similar elution volume. Compared to low-Zn leaf extracts, high-Zn leaf extracts contained a higher proportion of Zn incorporated into high molecular weight components, and higher content of the amino acids Cys, Glu, Gly, and Asp in the low molecular weight Cd-Zn complex. The peptides isolated by high performance liquid chromatography (HPLC) of the Cd-Zn complex from the low- or high-Zn leaf extracts did not have an amino acid composition identical to phytochelatins. We concluded that

1. Sequestration of Cd or Zn via phytochelatin does not occur in leaves of lettuce containing levels of those metals representatives of Zn-Cd or Cd-only contaminated crops; and
2. Higher Cys, Glu, Gly, and Asp content in high-Zn than low-Zn leaves could lower Cd absorption in animals fed high-Zn crop diets, by enhancing metallothionein synthesis or changing Cd or Zn speciation in the animal gut.

     

Short-term and long-term effects of cadmium,chromium, copper,nickel, lead and zinc on soil microbial respiration in relation to abiotic soil factors

Summary The inhibition of the respiration rate by the heavy metals, Cd, Cr, Cu, Pb, Ni and Zn was investigated in five Dutch soil types in relation to the length of time these heavy metals were present in the soil. The amounts of heavy metal added as chloride salts to the soils were 0, 55, 150, 400, 1000, 3000 and 8000 g·g^–1, respectively. The measurements were carried out both immediately after the addition of the heavy metals and approximately 18 months later. The inhibition during the first two to eight weeks was not obscured by an extra nutrient flush to drying. During the 18 months, the toxicity decreased but was still significant. Inhibition was greatest in the sandy soil and least in the clay soil. In a loam soil and in a sandy peat soil, the inhibiting effects were intermediate, but distinct. The main abiotic factors responsible for these different degrees of inhibition were the clay fraction for Cd, the Fe content for Cu, Pb and Zn and the pH for Ni. Although clay, Fe, and Mn together with the organic matter fraction, determine the total cation exchange capacity of soil, their contribution to the toxicity of heavy metals may be antagonistic. The latter may increase the mobility due to chelation and therefore possibly increase the toxicity, while the other factors may bind the heavy metals and therefore decrease the toxicity.     

重金属对土壤中萝卜种子发芽与根伸长抑制的生态毒性

高等植物是生态系统中的基本组成部分。一个平衡、稳定的生态系统生产健康、优良的高等植物。反之 ,一个不稳定或受到外来污染的生态系统 ,对高等植物的生长可带来不利和可见的负面影响。因此 ,利用高等植物的生长状况监测土壤污染程度 ,是从生态学角度衡量土壤健康状况 ,评价土壤质量的重要方法之一[4 ,6] 1) 。土壤生态毒理学评价方法是对化学分析方法的重要补充。目前已建立的高等植物毒理试验有三种方法 ,即 1根伸长试验 ;2种子发芽试验 ;3早期植物幼苗生长试验[3 ,5,6,10 ] 。最初 ,这类试验主要用于纯化学品的毒性检验 ,但随着对土壤…     

A Dual Role of Se on Cd Toxicity: Evidences from the Uptake of Cd and Some Essential Elements and the Growth Responses in Paddy Rice

This study was carried out to investigate the effects of selenium (Se) on the uptake and translocation of cadmium (Cd) and essential elements in paddy rice (Oryza sativa L., Shuangyou 998). Selenium could alleviate/aggravate Cd toxicity in paddy rice, which depended on the dosages of Se and/or Cd. When Cd treatment level was as low as 35.6 μM, ≤12.7 μM Se could inhibit the uptake of Cd in paddy rice and increase the biomass of paddy rice; however, with Cd levels reaching 89–178 μM, the addition of Se resulted in increases in Cd uptake and exacerbated the growth of paddy rice. Cd always inhibited the uptake of Se. Cd alone suppressed the uptake of Ca, Mg, Mn, Cu, and Zn; however, Se reversed the decreases in the concentrations of the said elements, suggesting an element regulation mechanism to relieve Cd toxicity. Without Cd in the solution, low doses of Se increased the biomasses of shoots and roots at the expense of the more or less decreases in the concentrations of Ca, Mg, K, Fe, Mn, Cu, and shoot Zn, indicating an antagonistic effect of Se on these cations. The presence of Cd could also reverse these decreases especially at the highest treatment levels for both Se and Cd, also suggesting an element regulation mechanism responsible for the detoxification of high dosages of Se. Consequently, when Se is used to alleviate Cd toxicity, attention must be paid to the Cd pollution extent and doses of Se supplement.