镉,铜抗性植物细胞株的增长及元素吸收特性

在含Cd、Cu浓度100、200μMol的培养基中进行驯化培育,获5株抗Cd细胞株及3株抗Cu细胞株。驯化株细胞相对增长率显著高于亲株,在Cd、Cu浓度波动较大的条件下,驯化株细胞增长率仍较稳定;驯化株对Cd、Cu的蓄积性因细胞种类不同而异,或具有降低对Cd、Cu的吸收,使抗性增加的机制,或对Cd、Cu有更强的吸收特性,但浓缩系数相对较稳定,从而抵御环境中Cd、Cu的波动,驯化株对营养元素的吸收呈现高于亲株或低于(近于)亲株两种类型,推断具有通过新陈代谢调节的适应机制;终止驯化的回复株一定程度保留了驯化获得性,但有向亲株回复的趋势,推断所获抗性非基因控制类型。     

土壤重金属污染的酶学诊断:紫色土Cd、Cu、Pb和As对水稻根系脱氢酶的影响

本文通过酸性紫色土和石灰性紫色土中不同浓度Cd、Cu、Pb、As对水稻根系脱氢酶的影响研究,揭示了脱氢酶受抑制与产生抗性的过程。在低浓度时,土壤Cd、Cu、Pb、As对脱氢酶的影响较敏感,能因元素的不同性质反映土壤类型影响的差别。最后,以脱氢酶受抑制与初始抗性峰出现的转折点相应的土壤浓度为依据,确定了两种紫色土Cd、Cu、Pb、As的临界浓度。     

土壤重金属污染的酶学诊断:紫色土Cd、Cu、Pb和As对水稻根系脱氢酶的影响

本文通过酸性紫色土和石灰性紫色土中不同浓度Cd、Cu、Pb、As对水稻根系脱氢酶的影响研究,揭示了脱氢酶受抑制与产生抗性的过程。在低浓度时,土壤Cd、Cu、Pb、As对脱氢酶的影响较敏感,能因元素的不同性质反映土壤类型影响的差别。最后,以脱氢酶受抑制与初始抗性峰出现的转折点相应的土壤浓度为依据,确定了两种紫色土Cd、Cu、Pb、As的临界浓度。     

铜、镉胁迫下外源NO介导的番茄解毒途径

一氧化氮(NO)作为信号分子,在抵御重金属胁迫中起重要作用,但对不同离子胁迫下的解毒机制尚缺乏研究.本研究采用营养液培养法,研究了铜(Cu)、镉(Cd)单一或复合胁迫下,番茄幼苗对Cu、Cd的吸收转运特性及对外源NO的响应机制.结果表明: 50 μmol·L^-1的Cu²⁺、Cd²⁺均显著抑制番茄植株的生长,其中Cd胁迫对生长的抑制效应远高于Cu胁迫.Cu、Cd单一或复合胁迫均使番茄根系Cu、Cd含量显著升高,但根系对Cu、Cd吸收存在严格选择性.根细胞对必需元素Cu表现出“奢侈吸收”的现象,而对毒性较强的Cd则吸收相对较少,胞内Cd浓度仅为Cu的1/10左右.外源NO处理可不同程度地缓解Cu、Cd胁迫,其中缓解Cd胁迫的效能更强.番茄对被动进入细胞的Cu、Cd具有相似的解毒机制:一方面,Cu、Cd胁迫诱导细胞质中产生谷胱甘肽(GSH)、植物螯合肽(PCs)和金属硫蛋白(MTs),络合过多的Cu、Cd离子,降低其生物毒性;另一方面,过多的Cu、Cd离子或螯合物被转运至液泡区隔化.外源NO通过调控GSH-GSSG(氧化型谷胱甘肽)氧化还原状态及GSH-PCs代谢方向的改变,促进Cu、Cd离子转运至液泡区隔化来缓解胁迫抑制;NO还可诱导植株叶片或根系表达更多的金属硫蛋白、GSH和PCs,而且上述响应普遍存在叠加效应.这可能是NO介导番茄对Cu、Cd胁迫的另一主要解毒途径.     

Cd-Cu复合胁迫对黄菖蒲叶片及根系中Cd和Cu的积累及其迁移率的影响

采用水培法研究了Cd-Cu复合胁迫(5 mg·L-1Cd-10 mg·L-1Cu;5 mg-L-1Cd-20 mg·L-1Cu;25 mg·L-1 Cd-10 mg·L-1Cu;25 mg·L-1Cd-20 mg·L-1Cu)条件下黄菖蒲(Iris pseudacorus L.)叶片和根系对Cd和Cu的积累作用及黄菖蒲体内Cd和Cu迁移率的变化规律.结果表明,在50 d的胁迫期内,黄菖蒲叶片和根系中的Cd和Cu含量分别随培养液中Cd和Cu浓度的提高而增加,并随胁迫处理时间的延长基本呈增加的趋势,在胁迫末期明显提高.在不同浓度Cd-Cu复合胁迫条件下,黄菖蒲根系中的Cd和Cu积累量明显高于叶片.在Cd浓度不变的条件下,黄菖蒲叶片和根系中的Cd含量随培养液中Cu浓度的提高而增加;在Cu浓度不变的条件下,黄菖蒲叶片中Cu含量随培养液中Cd浓度的提高而降低.在不同胁迫时间,黄菖蒲植株对Cd的迁移率不同,但培养液中Cd的浓度较高,黄菖蒲植株对Cd的迁移率也较高;黄菖蒲植株对Cu的迁移率随胁迫时间的延长基本上呈上升趋势.研究结果显示,在Cd-Cu复合胁迫条件下,Cu对黄菖蒲体内Cd的吸收具有一定的协同吸收作用,而Cd对Cu的吸收则有一定的拈抗作用.     

转mMT—Ⅰ基因烟草对Cd^2＋的耐受力及其细胞学研究

转小鼠金属硫蛋白 ( m MT- )基因烟草 ( N icotiana tabacum L.;90 0 82 )的 F1和对照株对 Cd2 的抗性有明显差异。在含有不同浓度 Cd2 ( 0～ 1 0 0 μmol/L)的培养基上转基因植物生长正常 ,表现出了对Cd2 的高度抗性。而对照株在 Cd2 2 0 μmol/L的浓度下即受到毒害。转基因株中 Cd2 总量及结合态和游离态 Cd2 含量、根的生长速率、细胞分裂指数均明显高于对照 ,而染色体畸变率则明显低于对照株。Southern blot、Western blot、Cd2 含量的原子吸收测定、镉 /血红蛋白饱和法分析 m MT含量表达的结果证明 :转基因株对 Cd2 的高度抗性是 m MT- 基因表达的结果。在不含 Cd2 的培养基上转基因株和对照株均未发现 MT的表达 ,而在含 Cd2 1 0 0μmol/L的培养基上只有转基因株的根与叶检测到 MT的表达。     

中国沙棘幼苗对土壤镉生理耐性和富集转运特征的性别差异

为探究中国沙棘对土壤镉(Cd)胁迫的性别响应差异,该研究以中国沙棘2年生幼苗为材料,利用盆栽试验研究在不同浓度Cd处理下(0(CK)、25、50、100和200 mg·kg^-1)雌、雄株幼苗的生长、叶片生理特性以及Cd富集特征的差异。结果表明：(1)Cd处理下中国沙棘幼苗雌、雄株的株高和基径生长以及各器官生物量均表现出低浓度(<50 mg·kg^-1)促进,高浓度(> 100 mg·kg^-1)抑制的现象;低浓度Cd处理下雌株的株高、基径增长率和生物量的增幅均高于雄株;高浓度Cd处理下(200 mg·kg^-1)雄株株高增长率、叶生物量和总生物量分别较CK显著降低,而雌株均未显著下降。(2)随着Cd浓度升高,雌、雄株叶片光合色素含量和抗氧化酶活性呈先升后降的变化趋势,丙二醛(MDA)和渗透调节物质含量呈上升趋势;Cd浓度为50～200 mg·kg^-1时,雌株叶片的光合色素含量、抗氧化酶活性和渗透调节物质含量均高于雄株,而MDA含量始终低于雄株。(3)随着Cd浓度升高,雌、...     

匍茎翦股颖对Cu2+、Zn2+、Cd2+与Pb2+ 胁迫的生长响应与阈限浓度

采用砂培法,研究了匍茎翦股颖对Cu2+、Zn2+、Cd2+与Pb2+胁迫的生长响应及阈限浓度,结果表明:种子萌发率随着4种重金属浓度的增加而下降。对株高的影响是当重金属浓度小于100mg/L时会促进株高生长,高于100mg/L则产生抑制作用。Cu2+显著抑制根系生长,并随浓度的增加抑制效应愈加显著;在Cu2+浓度为600mg/L时匍茎翦股颖的根长比对照下降了93.75%。Cu2+、Zn2+、Pb2+浓度小于200mg/L时会促进地上生物量的增加,但高于200mg/L时,地上生物量会随着3种重金属的增加而减少。Cu2+、Zn2+浓度小于100mg/L或Cd2+、Pb2+浓度小于200mg/L会增加叶绿素的含量,高浓度会降低叶绿素的含量;Cd2+在浓度为600mg/L时显著降低叶绿素含量,与对照相比,下降了43.55%。匍茎翦股颖生长的综合效应分析表明,匍茎翦股颖对Cu2+胁迫最敏感,具有较低的阈限浓度,而Zn2+胁迫对匍茎翦股颖的生长影响最小,阈限浓度相对较高。     

桉树对矿区污染土壤中Cu和Cd的耐受机制

为明确桉树对土壤中Cu和Cd的耐受机制,采用某矿区实际污染土壤进行盆栽实验,研究了桉树对Cu和Cd的吸收和累积,分析了桉树根、茎和叶中Cu和Cd的亚细胞分布。实验结果表明,随土壤污染程度的增加,重金属的转运系数降低,Cu和Cd滞留在桉树根部。重度污染土壤中,桉树根部的Cu和Cd分别占植株总量的43%和90%。随污染程度的增加,桉树根部Cu和Cd的含量先增加后稳定,重度污染土壤中,桉树根部Cu和Cd的累积系数降低,对Cu和Cd的吸收受到限制。桉树吸收的Cu和Cd主要分布在根、茎和叶的细胞壁组分(45%),随土壤污染程度的增加该比例大致保持稳定。重度污染土壤中,Cu和Cd在桉树根部可溶组分中的比例增加。综上所述,根部的滞留作用、根部的吸收限制、细胞壁固持作用及可溶组分的区隔化作用,是桉树耐受污染土壤中Cu和Cd的主要机制。     

产金属硫蛋白酵母菌原生质体电融合研究

采用原生质体电融合技术,由不能水解淀粉、细胞生物量低,只抗Cu²⁺、金属硫蛋白(MT)中cys含量高的酿酒酵母(Saccharomyces cerevisiae,a)单倍体BD101-25和具淀粉水解能力、细胞生物量高、Cu²⁺、Cd²⁺抗性高、金属硫蛋白中cys含量低的异常毕赤酵母(Pichiaamomala,a)单倍体BD102-13获得4个融合株。融合组合有两亲株属间融合和单一亲株种内融合两类。融合株细胞体积、DNA含量均近似于两亲株细胞之和,并具有水解淀粉能力,Cu²⁺、Cd²⁺抗性高,细胞生物量高,MT中cys含量高等特点。属间融合株Cu²⁺、Cd²⁺抗性的遗传性状稳定。     

Metal accumulation and metallothionein in brown trout, Salmo trutta, from two Norwegian rivers differently contaminated with Cd, Cu and Zn

In this work we have studied the accumulation of heavy metals in two brown trout (Salmo trutta) populations in their natural environment and the participation of metal binding to metallothionein (MT) in this process. Cd, Cu and Zn concentrations, total MT (including Cu MT) and Cd/Zn MT were measured in the gills, liver and kidney of trout inhabiting two rivers, one Cu-contaminated and the other Cd/Zn-contaminated, located at Røros, Central Norway. In both populations, high levels of Cu were found in the liver, whereas Cd was accumulated in liver and particularly in the kidney. The proportions of Cd/Zn MT and Cu MT in liver and kidney, but not in gills, reflected the accumulated and the environmental concentrations of these metals. The total Cu MT concentrations in the investigated tissues, however, were highest in trout from the river with the lowest ambient Cu concentration. It is suggested that MTs are of less importance in Cu-acclimated trout. The data also suggest that acclimation to a Cu-rich environment involves reduced Cu accumulation or increased Cu elimination. In trout from the Cd-rich environment, this metal was mainly bound to MT, whereas in trout from the Cu-rich environment Cd was also associated with non-MT proteins. These findings emphasize the importance to determine both Cd/Zn MT and Cu MT levels, when the participation of this protein in metal handling in trout tissues is investigated.     

Phytoextraction of initial cutting of Salix matsudana for Cd and Cu

Salix species are widely used as vegetation filters because of their flourishing root system and fast growth rate. However, studies have yet to determine whether the root system functions in vegetable filters with mixed heavy metal (HM) pollution or whether initial cutting participates in the phytoextraction of HMs. This study aims to determine the function of the root system and initial cutting as vegetation filters in the absorption and accumulation of Cd and Cu. Thick (>1?cm in diameter) and fine (<1?cm in diameter) initial cuttings of Salix matsudana were planted in a nutrient solution with single and mixed (Cd?+?Cu) treatments. The roots of several initial cuttings were removed daily to eradicate rhizofiltration. Results revealed that the existence of the root system altered distribution and interaction of Cd and Cu in plant organs and enhanced tolerance and phytoextraction capacity of plants. The initial cuttings could also absorb and accumulate HMs in the early growth stages of willow without roots. Cu inhibited the plant absorption and accumulation of Cd and promoted Cd transport to shoots. Cd inhibited the Cu absorption of the root system. Our study provided essential data regarding woody species as vegetation filters of HM pollution.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

The expression of heterologous Fe (III) phytosiderophore transporter HvYS1 in rice increases Fe uptake,translocation and seed loading and excludes heavy metals by selective Fe transport

Many metal transporters in plants are promiscuous, accommodating multiple divalent cations including some which are toxic to humans. Previous attempts to increase the iron (Fe) and zinc (Zn) content of rice endosperm by overexpressing different metal transporters have therefore led unintentionally to the accumulation of copper (Cu), manganese (Mn) and cadmium (Cd). Unlike other metal transporters, barley Yellow Stripe 1 (HvYS1) is specific for Fe. We investigated the mechanistic basis of this preference by constitutively expressing HvYS1 in rice under the control of the maize ubiquitin1 promoter and comparing the mobilization and loading of different metals. Plants expressing HvYS1 showed modest increases in Fe uptake, root‐to‐shoot translocation, seed accumulation and endosperm loading, but without any change in the uptake and root‐to‐shoot translocation of Zn, Mn or Cu, confirming the selective transport of Fe. The concentrations of Zn and Mn in the endosperm did not differ significantly between the wild‐type and HvYS1 lines, but the transgenic endosperm contained significantly lower concentrations of Cu. Furthermore, the transgenic lines showed a significantly reduced Cd uptake, root‐to‐shoot translocation and accumulation in the seeds. The underlying mechanism of metal uptake and translocation reflects the down‐regulation of promiscuous endogenous metal transporters revealing an internal feedback mechanism that limits seed loading with Fe. This promotes the preferential mobilization and loading of Fe, therefore displacing Cu and Cd in the seed.     

污染条件下VAM玉米元素积累和分布与根际重金属形态变化的关系

为了了解重金属Cu、Zn、Pb、Cd在土壤－根际－植物系统中的行为,揭示VAM植物减弱土壤中过量重金属对植物生理毒的抗性机理,采用原子吸收光谱测定Cu、Zn、Pb、Cd在污灌土壤中生长的VA菌根玉米和无菌根玉米中的积累和分布,并用连接形态分析技术分析了菌根际中Cu、Zn、Pb、Cd的形态分布和变化趋势,结果表明,Cu、Zn、Pb、Cd在菌根玉米中的积累量比非攻根中积累量分别减少10％、18％和29％,Cd积累量没有改变,生长7周后,菌根玉米是非菌根玉米生物量的1．5倍,与对照土壤相比,根际中除Cu交换态显著增加外,Zn、Pb、Cd各形态相对改变量显著大于非菌根,且菌根根际上中Cu、Zn、Pb有机结合态增加量显著大于非根际土,说明菌根际金属向稳定状态转移的程度显著大于非菌根际,同时,讨论了根际金属形态对金属有效性的影响,及其与菌根植物金属抗性机理的关系。     

牛组织重金属含量与饲养环境的相关性

通过选择不同污染程度的区域进行取样,分析了贵州地区不同污染水平下牛组织中重金属(Cu、Zn、Pb、Cd)的含量和与饲养环境的相关性.结果表明:贵州不同污染水平下牛组织中的Cu、Zn基本符合国家食品卫生要求,Pb只有污染地区的肝脏和肾脏超过限量标准,Cd污染较严重,除非污染区肝脏外,牛肾脏和肝脏中Cd的平均含量均超过国家肉类制品卫生限量标准,但肌肉组织符合卫生标准;牛组织重金属元素含量与饲养环境中的土壤、饲料和饮用水源的重金属含量和污染程度密切相关,尤其是肾脏组织,其相关系数r＞0.78.饲料向牛组织的重金属迁移系数,随饲料元素含量的增加而逐渐降低,其中Cd的迁移系数最大,Pb的迁移系数最低;必需元素和有害元素在不同组织中的比值,随污染程度的增加而降低.肾脏的Cu/Cd和Zn/Cd值比其它组织低得多,Cd主要在肾脏中蓄积,Cu主要在肝脏组织蓄积,Zn主要在肌肉和肝脏,Pb主要在肾脏和肝脏.     

Eco-service enhancement in peri-urban area of coal mining city of Huaibei in East China

After 50 years of coal mining, Huaibei Mine, located at 50 km southeast of Xuzhou City in East China, has grown to a middle-size city of 600,000 people from a small village of 2000 farmers. The Zhahe Valley, with 400 km² of a built-up area and more than 100 km² of subsided peri-urban wetland at the city center, is surrounded by eight exhausted old mines and communities. In cooperation with the local city government, an ecological landuse change assessment and eco-city planning project has been carried out with a focus on the assessment, restoration and enhancement of the wetland as an eco-service to the community. The assessment includes relationships to Green House Gas emissions and heat island effects, as well as measures for a livable, workable, affordable and sustainable human settlement development through industrial transition, landscape design and capacity building. This paper will briefly introduce the main ecological approaches and results of the assessment, including measures such as changing the car-dominated transportation network to a rail-dominated network, transforming the coal-oriented high-carbon industry to a service-oriented low-carbon industry, the C-shape urban form to an O-shape with a green–blue core at the center, and the fragmentized collapsed land to integrative eco-service land.     

Insight into the pattern of heavy-metal accumulation in lichen thalli

BackgroundHeavy metals that pass through the plasmalemma are expected to influence on lichen metabolic processes; however, lichens may tolerate high concentrations of metals by sequestrating them extracellularly. Heavy metal accumulation level fundamentally determine the success of lichens in the colonisation of polluted sites; however, the proportions between extra- and intracellular metal concentrations in lichen thalli are still poorly recognized. In this study metal accumulation patterns of selected toxic trace elements, i.e. Pb, Cd, and micronutrients, i.e. Zn, Cu and Ni, in Cladonia cariosa thalli were recognised in relation to extra- and intracellular fractions.MethodsThe intracellular and total concentrations of Zn, Pb, Cd, Cu and Ni in lichen thalli collected from eleven variously polluted sites were determined by means of atomic absorption spectrometry. Additionally, organic carbon and total nitrogen contents as well as pH of soil substrate were measured.ResultsThe accumulation patterns differed between studied metal elements; the major part of Zn, Pb and Cd loads was accumulated extracellularly, whereas Cu and Ni accumulation was mostly intracellular. Like toxic trace elements, Zn was accumulated mainly extracellularly at high polluted sites. The non-linear models most reliably reflect relationships between intracellular and extracellular metal contents in C. cariosa thalli. The intracellular contents of Zn, Pb, Cd and Cu increased slower at higher than at lower extracellular concentrations. Moreover, at higher total concentrations of elements in the thalli, their extracellular proportions were markedly increased.ConclusionThe results suggest that in the face of extreme Zn-enrichment, lichens demonstrate the ability to accumulate the excess of Zn outside the cells. Therefore, it can be concluded that metal accumulation depend not only on the element but also on its abundance in the environment and direct availability for lichens. The studied species showed a defence against excessive intracellular accumulation when a given element is in excess. Such capability may facilitate the colonization of extremely polluted sites by certain pioneer lichens.     

Integrative approach gives new insights into combined Cd/Cu exposure in tobacco

Heavy metals are generally known to induce oxidative stress, but are rarely strategically studied in an embracive manner, taking into account interplay between their various effects. Furthermore, although metals in the environment are present in mixtures and interact with each other, their combined effects to organisms have been much less studied in comparison to individual effects. Here, we present a complete comprehensive study of cadmium (Cd)/copper (Cu) oxidative stress interactions in Nicotiana tabacum seedlings and adult plants. Plants were treated with Cd (10 and 15 μM), Cu (2.5 and 5 μM) and their combinations; seedlings during 1 month period and adult plants during the period of 7 days. Metal accumulation measurements showed that Cd and Cu influence each other uptake, with Cu reducing Cd translocation to shoots. PCA analysis showed that MDA and carbonyls, biomarkers of oxidative stress, as well as ascorbate peroxidase activity, highly correlated across tissues and with Cd content. Majority of toxic effects were caused by Cd-alone, while addition of Cu often resulted in damage alleviation. However, mixture of high concentrations of both Cd and Cu induced most adverse effects. In conclusion, our results indicate that Cu in lower concentration has antagonistic effect to Cd toxicity, while in higher concentration these metals interact additively in tobacco.