植物重金属转运蛋白研究进展

土壤中的有毒重金属不仅对植物有害,也可通过食物链危害人类和动物的健康.重金属转运蛋白在植物吸收、抵抗重金属的复杂机制中起着关键作用.植物重金属转运蛋白分为吸收蛋白和排出蛋白,其中,吸收蛋白转运必需重金属进入细胞,同时也会因为必需重金属的缺乏或离子之间的竞争而运载有毒重金属;排出蛋白是一类解毒蛋白,可将过量的或有毒的重金属逆向转运出细胞,或区室化于液泡中.目前,细胞内多种重金属转运蛋白基因的转录水平与重金属离子积累之间的联系已被揭示,并分离克隆出诸多相关蛋白家族成员.本文综述了近年来发现并鉴定的主要重金属转运蛋白的金属亲和性、器官表达特异性及细胞内定位等的研究进展.     

植物硫转运蛋白研究进展

硫转运蛋白在植物对硫酸盐的吸收和转运中起着重要的作用。已经在拟南芥、大麦和小麦等植物中分离到了40多种硫转运蛋白基因。这些基因序列与其他种类生物的硫转运蛋白基因序列有着高度的保守性。利用CLUSTAL程序建立的系统进化树将植物硫转运蛋白划分为5个亚群。使用多种拓扑预测程序推测出不同植物硫转运蛋白的共同结构特点是均含有12个跨膜域。在柱花草和大麦中,硫转运蛋白基因表达调控包括植物体内硫水平的负调控和O—乙酰丝氨酸的正调控两种方式。对硫转运蛋白的组织定位和功能研究表明,高亲和硫转运蛋白主要定位于根部,在根系硫酸盐吸收中起重要作用。     

植物重金属转运蛋白P_(1B)-ATPase结构和功能研究进展

植物调节体内重金属的累积量以维持自身生存,其中,金属阳离子转运蛋白发挥了关键作用。P1B-ATPase是在生物中广泛存在的P-ATPase中的一个亚族,也是P-ATPase多个亚族中唯一参与重金属稳态的转运蛋白。拟南芥中共发现8个P1B-ATPase。研究表明,P1B-ATPase在植物体内具有维持金属的稳态、转运以及金属解毒的功能;与金属离子在根部区域的活化、吸收、地上部分的运输、贮存,以及植物对重金属的耐受性均相关。以下综述了P1B-ATPase的进化分类、结构特征以及功能方面的最新研究进展,并展望了其在植物修复领域的应用前景。     

植物脂质转运蛋白的研究进展

高等植物脂质转运蛋白(lipid-transfer proteins,LTP)是一类小分子(约9 ku)的碱性蛋白质,已从多种植物中纯化出了LTP,且编码LTP的cDNA及基因也从不同植物中克隆.LTP能够在生物膜之间转运磷脂,因而认为LTP参与了细胞内生物膜形成.而近期的研究又发现LTP具信号肽,可从细胞内分泌到细胞外,位于细胞壁上,因而又对其在细胞内的转运脂质能力产生疑问.而有证据表明LTP参与了角质与腊质的形成、植物的抗病反应和植物对环境变化（温度、盐、干旱协迫）的适应.     

植物重金属超富集机理研究进展

植物超富集重金属机理主要涉及植物对金属离子高的吸收、运输能力,区域化作用及螯合作用等方面,其中跨膜运载蛋白的表达、调控对重金属超富集这一特性起了关键作用。金属阳离子运载蛋白家族主要包括CDF家族、NRAMP家族和ZIP家族等,在超富集植物中已克隆出多个家族的金属运载蛋白基因,这些基因的过量表达对重金属在细胞中的运输、分布和富集及提高植物的抗性方面发挥了重要作用。综述了近年来研究重金属超富集植物吸收、转运和贮存Zn、Ni、Cd等重金属的生理和分子机制所取得的主要进展。     

植物蔗糖转运蛋白

文章概述了植物蔗糖转运蛋白的结构、性质和类群的研究进展。     

液泡膜转运蛋白与植物耐盐性研究进展

液泡膜转运蛋白与植物耐盐性研究进展王宝山１邹琦２赵可夫１１（山东师范大学逆境植物研究所,济南２５００１４）２（山东农业大学基础部植物生理教研室,泰安２７００１８）ＡｄｖａｎｃｅｓｉｎｔｈｅＶａｃｕｏｌａｒＴｒａｎｓｌｏｃａｔｉｎｇＰｒｏｔｅｉｎｓａ...     

植物螯合肽的转运与功能研究进展

植物螯合肽（phytochelatins,PCs）是由植物螯合肽合酶催化谷胱甘肽合成的一类生物小分子,结构式为（γ-Glu-Cys）n-Gly（n=2-11）,在真菌和高等植物耐受重金属胁迫机制中具有重要作用。近年来,人们在Pc介导重金属脱毒害的分子机理研究上取得了重要进展,发JLSpHMT1和SpABC2是PC在裂殖酵母中介导重金属液泡区室化的主要转运蛋白,鉴定了拟南芥液泡膜PC转运蛋AtABCC1和AtABCC2。此外,PCs也可能在超积累植物细胞内对重金属脱毒害具有重要功能。     

质膜转运蛋白及其与植物耐盐性关系研究进展

植物细胞质膜有两种主要功能：⑴溶质运输（进出细胞）,溶质运输主要由转运蛋白完成;⑵信号传导,即接收信号并引发细胞生理生化响应。盐分过多对植物的伤害主要是离子毒害。质膜转运蛋白活性环境变化能做现迅速响应。本文简要叙述了植物细胞质膜转运蛋白类型、分子特性、生理功能及其活性调节。介绍了植物细胞质膜Ｈ＾＋－ＡＴＰａｓｅ、质膜氧化还原系统、质膜离子载体和离子通道对盐胁迫的响应及其这些响应与植物耐盐性之间的关     

植物中铵转运蛋白的研究进展

铵转运蛋白在众多生物中被克隆与鉴定,它是一种广泛存在于微生物、植物细胞及动物的细胞膜上主动转运铵离子的载体,分子量约为48kD,含有10～11个跨膜域.本文阐述了植物铵转运蛋白分离鉴定的过程,对于铵转运蛋白的结构、功能、基因表达调控等方面作了较详细叙述.不同氮素条件下,铵转运蛋白基因通过转录调控表现了对铵离子吸收转运的不同特点,使植物根系在较宽的浓度范围中吸收铵离子,为细胞内铵离子库的内稳态提供了理论依据.铵转运蛋白有助于作物更有效的吸收氮素,为农业生产粮食增收提供了有利保障.     

Root development and heavy metal phytoextraction efficiency: comparison of different plant species in the field

Heavy metal phytoextraction is a soil remediation technique which implies the optimal use of plants to remove contamination from soil. Plants must thus be tolerant to heavy metals, adapted to soil and climate characteristics and able to take up large amounts of heavy metals. Their roots must also fit the spatial distribution of pollution. Their different root systems allow plants to adapt to their environment and be more or less efficient in element uptake. To assess the impact of the root system on phytoextraction efficiency in the field, we have studied the uptake and root systems (root length and root size) of various high biomass plants (Brassica juncea, Nicotiana tabacum, Zea mays and Salix viminalis) and one hyperaccumulator (Thlaspi caerulescens) grown in a Zn, Cu and Cd contaminated soil and compared them with total heavy metal distribution in the soil. Changes from year to year have been studied for an annual (Zea mays) and a perennial plant (Salix viminalis) to assess the impact of the climate on root systems and the evolution of efficiency with time and growth. In spite of a small biomass, T. caerulescens was the most efficient plant for Cd and Zn removal because of very high concentrations in the shoots. The second most efficient were plants combining high metal concentrations and high biomass (willows for Cd and Zn and tobacco for Cu and Cd). A large cumulative root density/aboveground biomass ratio (L_A/B), together with a relative larger proportion of fine roots compared to other plants seemed to be additional favourable characteristics for increased heavy metal uptake by T. caerulescens. In general, for all plants correlations were found between L _A/B and heavy metal concentrations in shoots (r=0.758^***, r=0.594^***, r=0.798^*** (P<0.001) for Cd, Cu and Zn concentrations resp.). Differences between years were significant because of variations in climatic conditions for annual plants or because of growth for perennial plants. The plants exhibited also different root distributions along the soil profile: T. caerulescens had a shallow root system and was thus best suited for shallow contamination (0.2 m) whereas maize and willows were the most efficient in colonising the soil at depth and thus more applicable for deep contamination (0.7 m). In the field situation, no plant was able to fit the contamination properly due to heterogeneity in soil contamination. This points out to the importance and the difficulty of choosing plant species according to depth and heterogeneity of localisation of the pollution.     

Phytoremediation potential of some agricultural plants on heavy metal contaminated mine waste soils,salem district,tamilnadu

The Pot culture experiment performed for phytoextraction potential of selected agricultural plants [millet (Eleusine coracana), mustard (Brassica juncea), jowar (Sorghum bicolor), black gram (Vigna mungo), pumpkin (Telfairia occidentalis)] grown in metal contaminated soils around the Salem region, Tamilnadu, India. Physiochemical characterization of soils, reported as low to medium level of N, P, K was found in test soils. The Cr content higher in mine soils than control and the values are 0.176 mg/L in Dalmia soil and 0.049 mg/L in Burn &; Co soil. The germination rate low in mine soil than control soils (25 to 85%). The content of chlorophyll, carotenoid, carbohydrate and protein decreased in mine soils than control. The morphological parameters and biomass values decreased in experimental plants due to metal accumulation. Proline content increased in test plants and ranged from 0.113 mg g^?1 to 0.858 mg g^?1 which indicate the stress condition due to toxicity of metals. Sorghum and black gram plants reported as metal tolerant capacity. Among the plants, Sorghum produced good results (both biomass and biochemical parameters) which equal to control plant and suggests Sorghum plant is an ideal for remediation of metal contaminated soils.     

Effects of modified carbon black nanoparticles on plant-microbe remediation of petroleum and heavy metal co-contaminated soils

Abstract

Little is known about the effect of modified carbon black nanoparticles (MNCB) on the availability of heavy metals and petroleum degradation in petroleum and heavy metals co-contaminated soils. The overall objective of this study was to investigate the simultaneous effect of MNCB on heavy metal immobilization and petroleum biodegradation in co-contaminated soil in plant and plant-microbe combined remediation. The results showed that the petroleum degradation increased by 50% in petroleum-Cd co-contaminated soil and 65% in petroleum-Ni co-contaminated soil in plant-microbe combined remediation, comparing with the plant remediation and the application of MNCB did not show significant improvement on petroleum degradation in both plant and plant-microbe combined remediation. MNCB could significantly reduce the availability of heavy metals in soil and the uptakes of Cd and Ni by Suaeda salsa by roughly 18 and 10% and improve the growth of plant by alleviating the growth inhibition caused by heavy metals. The application of Bacillus subtilis and Sphingobacterium multivorum (heavy metal tolerant bacteria) inhibited the biomass of Suaeda salsa by enhancing the petroleum degradation. It could be concluded that MNCB played a major role in immobilizing the heavy metals and bacteria dominated the petroleum degradation in petroleum-metal co-contaminated soil.     

The phylogenetic tree gathering the plant Zn/Cd/Pb/Co P1B-ATPases appears to be structured according to the botanical families

Plant Zn/Cd/Pb/Co P_1B-ATPases (HMAs) play different roles, among which are the control of metal transport from the roots to the shoot and/or from the cytoplasm into the cell vacuole. Transferring the knowledge acquired on HMAs from model species to HMAs from other species requires one to identify orthologues in these other species. Through an extensive screening of the public sequence databases, 96 plant P_1B-ATPases showing orthology to any of the AtHMA1, AtHMA2, AtHMA3 or AtHMA4 isoforms were identified from 32 plant species belonging to 15 botanical families. The number of paralogues within a species varied greatly from species to species, even within a specific botanical family, suggesting that gene duplication events occurred after speciation. The phylogenetic tree gathering the Zn/Cd/Pb/Co P_1B-ATPases was strongly structured according to the botanical family to which the sequences could be related to. In particular, no strict orthology relationship links the Brassicaceae HMAs to the non-Brassicaceae or the Poaceae ones. Recent data showed that the sole rice HMA characterised to date displays different functional properties from the Arabidopsis HMAs. Altogether, data suggest that it might be risky to directly transfer the knowledge acquired through the study of HMAs in model plant species to HMAs from other species.     

Suitability of aromatic plants for phytoremediation of heavy metal contaminated areas: a review

Abstract

This review briefly elucidates the research undertaken and benefits of using aromatic plants for remediation of heavy metal polluted sites. A sustainable approach to mitigate heavy metal contamination of environment is need of the hour. Phytoremediation has emerged to be one of the most preferable choices for combating the metal pollution problem. Aromatic plants can be used for remediation of contaminated sites as they are non-food crops thus minimizing the risk of food chain contamination. Most promising aromatic plants for phytoremediation of heavy metal contaminated sites have been identified from families – Poaceae, Lamiaceae, Asteraceae, and Geraniaceae. They act as potential phytostabilisers, hyper accumulators, bio-monitors, and facultative metallophytes. Being high value economic crops, monetary benefits can be obtained by growing them in tainted areas instead of food crops. It has been observed that heavy metal stress enhances the essential oil percentage of certain aromatic crops. Research conducted on some major aromatic plants in this context has been highlighted in the present review which suggests that aromatic plants hold a great potential for phytoremediation. It has been reported that essential oil from aromatic crops is not contaminated by heavy metals significantly. Thus, aromatic plants are emerging as an ideal candidate for phytoremediation.

Highlights

? Aromatic plants hold a great potential for phytoremediation of heavy metal contaminated sites.

? Being high value economic crops, monetary benefits can be obtained by growing them in contaminated areas instead of food crops.

? Research done on some major aromatic plants in this context has been highlighted in the present review.     

环境重金属污染物的生物有效性

利用生态系统研究了白银有色金属冶炼矿区周围环境中重金属的分布及生物有效性。结果表明 ,工厂在冶炼过程中已造成 Pb、Cd、Cu、Zn对周围环境不同程度的污染 ,其含量与距工厂的距离呈负相关 ;重金属在各种生物体内均有不同程度的吸收和累积 ,其吸收累积量随重金属和生物种类的不同而有差异 ;土壤的污染 ,使农作物和牧草中 Pb、Cd含量超过动物的最大耐受量和中毒的临界值 ;动物研究发现 ,肾脏、骨骼和肝脏是机体内重金属蓄积的主要器官。因此 ,放牧动物可作为环境重金属污染状况的标识 ,对评价重金属环境污染对当地人群的危害也有重要意义     

Multivariate analysis of heavy metal and nutrient concentrations in sediments of Taihu Lake, China*

Taihu Lake is one of the largest freshwater lakes in China. The Lake is very shallow with a mean depth of 1.9 m and an area of 2428 km². Nutrient concentrations (Org-C, Tot-N and Tot-P) and heavy metal concentrations (Ag, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sr, Zn, etc.) in the lake's surface sediments were sampled at 13 locations. This was done to determine if industrialized areas along the lake's coastline were impacting the nutrient and heavy metal distribution of the lake's surface sediments. Principal Component Analysis (PCA) was used to assess the degree of contamination and spatial distribution of heavy metals and nutrients in different areas of Taihu Lake.A distinctive spatial distribution of heavy metals and nutrients was observed. Sediments from a large embayment of Taihu Lake called Lake Wulihu had significantly higher nutrient concentrations (Org-C, 2.05–3.83%; Tot-N, 0.28–0.54%; Tot-P, 0.10–0.33%) than any other area of Taihu Lake. These high nutrient levels were associated with the input of untreated domestic sewage from the large (circa one million people) City of Wuxi, which discharges its effluents into the Liangxi River. As a result, Lake Wulihu is the most eutrophic area of Taihu Lake. The nearby Meiliang Bay suffered from the worst heavy metal contamination in Taihu Lake (e.g. As, 64.0; Ag, 4.2; Cd, 0.93; Co, 14.2; Cr, 155.0; Cu, 144.0; Hg, 0.25; Ni, 79.8; Pb, 143.0 and Zn, 471 mg kg^–1). These high heavy metal concentrations were ascribed to the discharge of untreated and partially treated industrial waste water from Changzhou and Wujin via the Zhihugang River. Surface sediment samples from the east basin of Taihu Lake were characterized by high Org-C (1.0–2.3%) and Tot-N (0.18–0.37%) and low Tot-P (0.048–0.056%) concentrations. It is likely that macrophytes removal accounts for a major reduction of phosphorus in the sediments of the east basin of Taihu Lake.