秋茄对镉的吸收、积累及净化作用的研究

采用砂培研究红树植物秋茄幼苗在含镉0.0025—25ppm海水培养液中对镉的吸收积累、净化作用以及镉对秋茄的毒害作用。试验结果表明：秋茄植物体镉含量大小顺序为：根>胚轴>茎>叶．各器官镉含量(y)随培养液镉浓度(x)的增加而增加,两者呈显著的双对数线性正相关,根与培养液镉含量的回归方程为;logy=1.8039+0.4311logx。在含镉培养液中培养4个星期,不同器官对镉的富集作用明显,镉处理2.5ppb,叶、茎、胚轴、根的富集系数分别为62.4、113.6、187.2、705.2．吸收的镉主要积累于根部。25ppm镉处理组每株幼苗(干重6.18g)吸收镉量为239.47μg,其中根占植物体总镉量的75.6%．在所有浓度处理中,秋茄植物体对镉的吸收量为培养液总加镉量的2.4—36%。2.5ppm镉处理组10个星期内,根部镉积累量为538.74μg／g,未见明显受害,表明秋茄对镉的吸收积累能力和耐性都较强。幼苗受镉的毒害程度主要与根部镉含量有关。从天然条件生长的红树植物器官镉积累量来看,也表明秋茄群落对镉污染的吸收净化效果显著。     

单一与复合污染条件下两种敏感性植物对Cd、Zn、Pb的吸收效应

为了进一步研究镉、锌、铅 3种重金属元素间的相互作用以及对植物吸收重金属能力的影响 ,在模拟单一重金属污染试验研究的基础上 ,采用正交回归设计方案 ,研究了 Cd、Zn、Pb复合污染情况下紫花苜蓿和披碱草两种敏感性植物对 3种重金属的吸收效应。结果表明 ,在单一污染条件下 ,镉元素对紫花苜蓿生长的影响大于锌、铅 ,铅元素对披碱草生长的影响大于锌、镉 ;紫花苜蓿对于镉的吸收累积显著高于披碱草 ,植物内镉元素浓度最高达到 1 0 88.5 mg/kg,而披碱草对于铅元素的吸收则高于紫花苜蓿 ,植物内铅元素浓度最高达到 1 3 4 5 .5 mg/kg。在复合污染条件下 ,两种植物对铅、锌和铅、镉的吸收在不同浓度范围内分别存在存在着协同效应和拮抗效应 ;同时两种植物对锌、镉元素在实验涉及浓度范围内都存在着拮抗效应。这对于深入研究复合污染条件下重金属的土壤环境化学行为 ,对植物的综合毒性以及不同植物对重金属的吸收累积效应等 ,具有一定的参考意义     

施用尿素对土壤中Cd、Pb形态分布及植物有效性的影响

采用室外盆栽试验,研究了在镉(25mg·kg-1)、铅(1000mg·kg-1)单一污染及其复合污染的土壤中,施用不同剂量尿素(0、100、200、400、800mg·kg-1)对小麦根际和非根际土壤镉、铅形态、小麦植物体镉、铅浓度的影响,为重金属污染土壤的防治提供依据。结果表明:增加尿素施用水平显著提高了小麦不同部位镉、铅浓度,尿素施用促进小麦对镉、铅的吸收与其对土壤中镉、铅形态分布的影响紧密相关,尿素施用引起土壤pH下降,提高土壤中交换态镉、铅含量,而交换态是最易被植物吸收利用的部分,这是尿素施用提高镉、铅植物有效性的主要原因;与单一污染相比,镉、铅复合污染抑制了小麦对铅的吸收,但促进了小麦对镉的吸收。     

单一与复合污染条件下两种敏感性植物对Cd、Zn、Pb的吸收

为了进一步研究镉、锌、铅3种重金属元素间的相互作用以及对植物吸收重金属能力的影响,在模拟单一重金属污染试验研究的基础上,采用正交回归设计方案．研究了Cd、Zn、Pb复合污染情况下紫花苜蓿和披碱草两种敏感性植物对3种重金属的吸收效应。结果表明,在单一污染条件下．银元素对紫花苜蓿生长的影响大于锌、镉、铅元素对披碱草生长的影响大于锌、镉,紫花苜蓿对于镉的吸收累积显著高于：披碱草,植物内银元素浓度最高达到1088．5mg/kg。而披碱草对于铅元素的吸收则高于紫花苜蓿。植物内铅元素浓度最高达到1345．5mg/kg。在复合污染条件下．两种植物对铅、锌和铅、镉的吸收在不同浓度范围内分别存在存在着协同效应和桔抗效应;同时两种植物对锌、银元素在实验涉及浓度范围内都存在着拮抗效应。这对于深入研究复合污染条件下重金属的土壤环境化学行为,对植物的综合毒性以及不同植物对重金属的吸收累积效应等,具有一定的参考意义。     

土壤镉污染与作物

通过土壤镉污染对作物影响的盆栽模拟试验,以揭示重金属镉在土壤—植物系统中的转移、分布规律及其对植物生长、发育的影响。试验证明不同化合形态的镉施入土壤(砂壤质褐土,pH值8.2),水稻对镉吸收的多寡依次为CdCl2>CdSO4>CdO>CdS>CdCO3。白菜的镉吸收表现为CdSO4>CdCl2>CdO>CdCO3。土壤的不同镉浓度(施加CdCl2,以纯镉计)对作物影响的试验结果表明,可食部位达到食品污染标准(谷物含镉量0.4ppm、蔬菜0.2ppm为暂定标准)时的土壤镉污染临界值分别为：小麦、莴苣、白菜<1ppm,茄子、萝卜<2.5ppm,番茄、菜豆<20ppm。土壤因子的处理影响镉的活动性;降低土壤pH值,水稻的镉吸收增加。增施有机肥、ZnSO4、S、CaO、CaSO4可降低糙米含镉量13.4%一30%。白菜的镉吸收,由于增施有机肥、FeSO4、Fe2O3、CaO或S而降低菜叶含镉量28%一61%。以Cd,Zn比1:100或1:200施入土壤,叶内含镉量分别下降61%和76.4%,但白菜产量减少61%和76%。     

‘新选七叶’油菜对土壤3种重金属的吸收和累积特征

以‘新选七叶’油菜为研究对象,采用土培方法,研究在不同浓度重金属(镉、铅、汞)胁迫下,油菜对重金属的吸收和积累特征,并探讨重金属在土壤—蔬菜间的迁移情况。结果表明:不同重金属在植物不同部位的分布和积累规律存在差异,镉和汞在植株上的积累规律为根叶茎,而铅在植株上的积累规律为根茎叶。油菜根部对重金属的累积能力远高于茎和叶,根部对三种重金属的吸收富集能力为镉汞铅。油菜各部位重金属含量与土壤重金属浓度呈显著正相关(r20.859)。以蔬菜可食部位重金属含量的最大限量为标准(GB 15201-1994、GB 14935-1994、GB 2762-1994),计算得出土壤中对应的镉、铅、汞临界值分别为0.362、43.62、2.892μg/g。     

植物吸收、转运和积累镉的机理研究进展

重金属镉(Cd)虽然不是植物生长的必需矿质元素,但依然能被植物吸收。且部分植物具有富集镉的特点,从而导致农产品镉含量超标,并通过食物链危害人类健康。研究植物吸收、转运和积累Cd的机理,对于培育低镉作物品种、降低农产品镉含量,以及选育超富集镉植物,修复镉污染土壤具有重要意义。从影响植物吸收Cd的因子,植物吸收、转运和积累Cd的机理以及植物拒Cd和富集Cd的分子机制等方面进行综述,以期为低镉作物的研究以及Cd污染土壤的综合治理提供一些参考。     

水稻土施硅对土壤-水稻系统中镉的降低效果

水稻中镉的积累造成人类健康的风险,增加水稻硅素能减轻镉中毒症状,降低稻米镉积累,但是硅对重金属的作用机理尚不清楚。主要研究了在中度和高度镉污染的土壤中,通过施用固态和液态的富硅物质对土壤-水稻系统中镉的吸收和转运的影响,探明决定镉和硅在根与芽的质外体和共质体中的作用机理。试验结果表明:(1)在中度和高度污染的土壤中,镉在土壤-作物系统中的转移和积累情况是不同的,可以通过富硅物质中的单硅酸与镉离子的相互作用,增加镉在硅物质表面的吸附来减少镉在土壤中的流动;(2)富硅物质可以降低水稻根和芽中镉的积累,在高度镉污染的情况下,施用硅可以使镉大量积累在水稻根及其共质体中,并降低根及其共质体中镉的转换和积累;(3)新鲜土壤中水萃取态的单硅酸含量与镉在土壤-作物系统中的流动性、转运以及积累等主要参数密切相关。     

5种湿地植物对土壤重金属的富集转运特征

选择芦苇、水葱、千屈菜、扁秆藨草、长苞香蒲5种湿地植物进行盆栽实验,比较它们对土壤中的5种重金属镉、铬、汞、铅、锌的富集特性,分析重金属在各植物体和土壤中的动态分布,以评价所测植物对土壤中重金属的综合富集能力,为利用植物修复金属污染土壤提供理论依据和技术支持。结果表明:(1)种植湿地植物对土壤重金属的富集效果显著高于无植物对照,且随着处理时间的延长,土壤中重金属镉、铬、汞、铅、锌的含量均呈下降趋势。(2)湿地植物对重金属镉、铬、汞、铅、锌的富集效果差异显著,其中水葱根部对重金属镉的富集系数最大,芦苇根部对重金属铬、汞、铅、锌的富集系数均最大,千屈菜、扁秆藨草和长苞香蒲根部对5种重金属的富集系数均较小;芦苇地上部分对金属镉的富集系数最大,千屈菜地上部分对金属铬、汞、铅的富集系数均最大,水葱地上部分对金属锌的富集系数最大。(3)5种湿地植物对重金属镉、铬、汞、铅、锌的转移系数差异显著,其中扁秆藨草对土壤中镉、铬、铅、锌的转移系数均为最大,对铬和锌的转移系数均大于1,长苞香蒲对铬的转移系数大于1,仅次于扁秆藨草。其他3种植物对5种重金属的转移系数均小于1。研究表明,5种湿地植物对重金属Cd、Cr、Hg、Pb、Zn都有富集和转移的能力,但不同植物对不同重金属的富集效果不同。     

铅对几种作物生长的影响及其在植物体内的积累

根据将醋酸铅溶液施入土壤及喷洒叶片的盆栽试验可以确定：(1)铅对植物的毒性不大,植物对铅的忍耐力很强。目前自然界中的铅污染程度不足以直接伤害植物本身。(2)溶液中的铅可以被植物的根系吸收,也可以被叶片直接吸收。吸收量与环境中的铅浓度成正比。(3)铅在植物体中移动性很小,根吸收的铅主要积累在根部,叶片吸收的铅主要积累在叶部。有少量铅可以向上或向下转移,但极少能进入果实的内部及块根的淀粉中。     

Uptake of six heavy metals by oat as influenced by soil type and additions of cadmium,lead, zinc and copper

Summary The influence of heavy metal additions on availability and uptake of cadmium, lead, zinc, copper, manganese and iron by oat was studied. The experiments were carried out as pot experiments using sandy loam, sandy soil and organic soil. Selective extractants were used to remove metals held in different soil fractions.Lead and copper were preferently bound by organics and oxides, zinc by oxides and inorganics, and cadmium by inorganics and organics.Addition of cadmium to the soils resulted in higher cadmium concentrations in all plant parts but lower concentrations of lead, zinc, copper, manganese and iron, and the accumulation indexes of these metals were also lower when cadmium was added to the soil.Addition of cadmium plus lead, zinc and copper resulted in higher cadmium concentrations in leaves and straw of plants grown in sandy loam and sandy soil, but lower concentrations when plants were grown in organic soil as compared with the results when cadmium was added separately. The transfer of cadmium, lead, zinc and copper from soil to plant was greatest from sandy soil, and zinc and cadmium were more mobile in the plant than were lead and copper.Cadmium concentrations in leaves correlated significantly with CaCl₂ and CH₃COOH extractions in sandy loam and sandy soil and with CH₃COOH extractions in organic soil.Generally, the total metal uptake was lowest from organic soil.     

Antioxidant capacity of sage grown on heavy metal-polluted soil

Oxidative stress response and essential oil composition of sage (Salvia officinalis L.), grown on industrially polluted soil were studied. Sage plants were grown on the soil polluted with Cd, Cu, Pb, Zn, and non-polluted control soil. One-year-old sage possessed a high potential for heavy metal accumulation mainly in the roots. Heavy metal pollution resulted in root and shoot dry biomass inhibition. The increased levels of hydrogen peroxide and MDA showed that the heavy metal uptake caused oxidative stress. The increase towards the control was observed in the levels of glutathione, ascorbate, dehydroascorbate, catalase, dehydroascorbate reductase, and glutathione peroxidase. Weak activities of the most enzymes of the ascorbate-glutathione cycle allowed to suppose that H₂O₂ neutralization is rather non-enzymatic than enzymatic process. Observed decline in α- and β-thujones and elevated camphor content in the sage leaves did not indicate a deterioration of the essential oil quality. Sage grown on heavy metal-polluted soil successfully accumulated cadmium, lead, and zinc, which is resulted in plant biomass inhibition, but essential oil yield and quality was not declined.     

Interactive effects of cadmium,lead and zinc on root growth of two metal tolerant genotypes ofHolcus lanatus L.

Lead and zinc tolerant genotypes ofHolcus lanatus L. were grown in culture solution at different cadmium, lead and zinc concentrations, and combinations. In all treatments, an increased inhibition of root length with increasing concentrations of heavy metals was observed. Growth of genotype 1 was better than that of genotype 2 in all treatments, suggesting that genotype 1 is more tolerant. The better root growth of genotype 1, at different cadmium concentrations, than that of genotype 2, indicated the existence of a co-tolerance or greater tolerance of genotype 1 to cadmium. Heavy metal combinations resulted in increased lead or zinc uptake by plants, while cadmium was decreased. In a lead-zinc combination, decreased lead and increased zinc uptake were detected. The different interactive effects of heavy metals on root growth of genotype 1 (additive or synergistic) and genotype 2 (additive or antagonistic) may suggest their differential susceptibility to the above metals.     

Investigation of Vetiver Grass Capability in Phytoremediation of Contaminated Soils with Heavy Metals (Pb,Cd, Mn,and Ni)

ABSTRACT

Soil contamination with heavy metals has become a worldwide concern. A sustainable technology to mitigate heavy metal contamination is extremely important. Phytoremediation is a cost-effective method, environmentally friendly, and esthetically pleasing. The aim of this study was to investigate the potential of Vetiver phytoremediation of soils contaminated with heavy metals. This research was conducted as a factorial design with four different heavy metals (lead, cadmium, manganese, and nickel) with three varying levels and also three replications for each treatment. Statistical analysis of data was performed using SPSS19 software and analysis of variance, Duncan and Pearson correlation tests. The results showed that, the highest uptake rate was related to lead metal with 282.45 mg/kg of dry soil and 83.4% uptake percentage. Then, the mean and percentage of adsorption for cadmium, nickel and manganese were 248.3 mg/kg (53.2%), 69.4 mg/kg (65.5%), and 63.29 mg/kg (61%), respectively. Lead was found to be the main component of uptake by Vetiver plant. It was found that the roots of the plant have absorbed more heavy metals than the shoots. And at the roots in total 1089.05 and on average 363.01 mg/kg and at the shoots 901.19 and on average 300.39 mg/kg, the metals used were adsorbed on three levels and four treatments. The results of analysis of variance, Duncan test and Pearson correlation showed that the effect of applied treatments on lead uptake in roots and shoots increased significantly (P ≤ 0.05) with increasing levels of treatments. The biological concentration factor was more than one, and the transfer factor was close to one. Therefore, it can be used as a phytostablization plant. The results showed that Vetiver can be considered as a refining plant due to its vegetative characteristics, cost-effectiveness and high adaptation to environmental conditions.     

木本植物对大气重金属污染物耐性的研究

本文在污染现场调查研究、试验研究和单一毒物接触试验的大量数据基础上,论述了木本植物对大气重金属污染物一一铅、镉、铜、锌的耐性。查明了大气重金属污染物引起叶片可见伤害症状需要很高的剂量。糖槭以2000ppm硝酸铅溶液浸泡涂抹枝叶,三天后出现轻度可见伤害症状,叶中铅积累量高达802ppm。旱柳以500ppm氯化镉溶液浸泡涂抹枝叶,叶中积累量达66ppm,十天内未出现可见症状。大气重金属污染物——铅、镉、铜、锌对叶片造成的急性伤害症状是相似的,而与土壤中相同污染物引起的急性伤害具有差别。木本植物对大气重金属污染物的耐性很强,在以大气重金属污染为主的复合污染现场,一些幼龄树木的叶片吸铅量达500—800ppm,超过背景浓度的120倍;吸镉量10—18ppm,超过背景浓度的139倍,吸铜量100—239ppm,超过背景浓度的5—12倍,吸锌量500—700ppm,超过背景浓度的9—20倍只出现较轻的受害症状。在相对清洁区,对幼树叶片进行单一毒物接触试验,一些主要绿化树木的叶片吸铅量达200—600ppm,吸镉量20—60ppm并不出现可见症状。木本植物对大气重金属污染物具有较强的耐性,因而为生物防治大气重金属污染开辟了广阔的前景。     

The influence of heavy metals upon the growth of sitka-spruce in South Wales forests

Summary Experiments on sitka-spruce seedlings grown in acidic peaty gley soils under green-house conditions, where the soils where doped with increasing amounts of Cd, Cu and Pb up to maximum levels of metal added of 16 ppm, 32 ppm and 400 ppm respectively, showed that the levels of Cd and Pb in shoots and roots increased with increasing levels in the soil, whereas levels of copper appeared to be independent. The addition of these three metals to the soils did not influence the uptake of other heavy metals, or of the nutrients potassium or calcium. Increases in the shoot cadmium levels significantly reduced the yields of the plant shoots. However, the plant yields were only affected by the highest level of lead that was added to the soil (400 ppm Pb) and unaffected by all the copper treatments (0–32 ppm Cu in the soil). The lengths of the sitka-spruce roots were reduced when cadmium and lead levels in the soil exceeded certain threshold concentrations (2.5 ppm total Cd, where 0.3 ppm was extractable with 0.5 M acetic acid; and 48 ppm total Pb, where 1.7 ppm was extractable). However, root lengths were not reduced by copper. This was probably related to the fact that copper appears to be relatively unavailable in the type of soil used, as only 1.1. ppm Cu was extractable from a total of 32 ppm Cu added. Root branching was apparently reduced by increases in the soil levels of cadmium, copper and lead. The roots of some control plants had symbiotic mycorrhizal associations (4 out of 19 plants), whereas the roots of all the plants grown in the soils with added heavy metals did not develop these.     

Characteristics of Phytogeochemistry in Copper Mine Area of Hongtou Shan,Liaoning Province

The contents of copper, zinc, lead nickel and cadmium for 322 samples of 44 species growing on copper mine area of Hongtou Shoo were determined. The results showed that the average contents of zinc, nickel, lead, cadmium in dry matter are 51.313 ppm, 1.536 ppm, 0.361 ppm and 0.058 ppm respectively. The variable range of zinc and cad- mium contents is larger, difference between minimum and maximum value is about 30–40 times. Zinc, lead and nickel contents in leaves of xylophyta in dry matter are mostly higher than in branches, but cadmium content of branches in dry matter is higher than leaves. The contents of lead and zinc in plants of minerelization areas are higher than that in non-minerelization areas. The results of correlative analysis showed that the linear regression between the metal contents in plants and soils are significant, for example, Lespedeza bicolor Thalictrum thumbergii, Arundinella hirta et al. It is important in phytogeochemical methods of prospecting for mineral. However, the correlative coefficients between the elements contents in leaves and branches of Quercus liaotungensis and in soils are not obvious. The correlative coefficient of nickel in plants and zinc, lead, cadmium and organic matter contents in soils are mostly negative value, without significant correlation. The results of the principal component analysis showed that the correlation of cadmium and zinc is significant among five elements in the plants. The contributive rate of first principal component is 33.94%, the positive target of the main target constitute is cadmium and zinc.     

木本植物对大气重金属污染物——铅、镉、铜、锌吸收积累作用的研究

对环境污染除必须采取人工治理措施外,还必须充分发挥自然净化作用,才能取得经济合理和维护生态系统动态平衡的目的。 绿色高等植物特别是树木,对环境污染起着明显的净化和改善作用。因为它们的生物产量高,占有很大的空间,有巨大的根、茎、叶面积作用于环境,并对污染物具有一定的吸收积累或降解作用;生活周期长,有较长的时间与周围环境相互作用与影响,同时吸收积累的污染物质不会在短期内转移释放到环境中;此外,大部分树木是以保护环境或生产木材为主要目的,因而吸收积累的污染物不进入食物链对人产生危害。所以树木在保持和维护生态系     

Influence of lead,cadmium, and nickel on the growth ofMedicago sativa (L.)

Summary Alfalfa (Medicago sativa L.), cv. Iroquois, was grown in the greenhouse in soils amended with additions of either lead, cadmium, or nickel. Metals, at rates varying from 0–250 ppm, were not uniformly mixed but were placed close to the soil surface so as to simulate surface deposition. In one series of experiments the sulphate salt of each metal and two soils were used. In a second series of experiments the nitrate salts and one soil were used. Neither salt of lead significantly depressed alfalfa yields. Both salts of either cadmium or nickel significantly depressed yields. Additions of all metals to the soil resulted in both increased metal uptake and concentrations in alfalfa tissue, particularly for cadmium and nickel. The highest tissue concentrations of cadmium and nickel were associated with plant stunting and necrosis. However, at rates of 125 ppm and less, substantial increases in cadmium and nickel concentrations were obtained frequently without serious yield reductions. Generally, metal concentrations were greatest in the first harvest following metal application. Concentration and uptake of lead and cadmium were greater when the metal was applied to the soil as nitrate than when applied as the sulphate salt.