植物修复技术在近海污染治理中的研究与应用

对国内外有关近海污染的植物修复技术研究进展进行综述,简述植物修复的6种作用机理,阐明植物修复对海水养殖富营养化、石油等有机物污染、赤潮、近海重金属污染以及污水净化的作用。最后指出应用植物修复技术治理近海污染具有以下优点:①对人类和海洋环境副作用小、生态风险小,易于为人们接受;②易于后处理,不会形成二次污染,很少有废物和排放物,遗留问题少;③具有一定的生态景观效应;④生物量大。     

Investigation of chromium phytoremediation and tolerance capacity of a weed,Portulaca oleracea L. in a hydroponic system

The present investigation was undertaken to study the growth, biomass, physiological‐biochemical responses and chromium (Cr) accumulation capacity of hydroponically grown Portulaca oleracea cuttings exposed to Hoagland solution supplemented with Cr(VI) (0.0, 0.1, 0.5, 1.0, 2.5, 5.0, 10 mg/L) for 30 days. The cuttings exhibited effective regeneration in Hoagland solution in comparison to deionized water. Plants demonstrated significant reduction in growth (root and shoot length, leaf area), biomass (root and shoot dry weight), pigments (total chlorophylls and carotenoids) and total soluble sugar content at higher concentration of Cr(VI) (10 mg/L). However, plants could tolerate Cr stress through significantly higher accumulation of proline and increased activity of peroxidase resulting in significant Cr accumulation (150–190 mg/kg dry weight) in harvestable parts of Portulaca. Thus, the results suggest application of P. oleracea for phytoremediation of Cr‐contaminated sites for the protection of environment.     

Characterization of the Sesbania rostrata Phytochelatin Synthase Gene: Alternative Splicing and Function of Four Isoforms

Phytochelatins (PCs) play an important role in detoxification of heavy metals in plants. PCs are synthesized from glutathione by phytochelatin synthase (PCS), a dipeptidyltransferase. Sesbania rostrata is a tropical legume plant that can tolerate high concentrations of Cd and Zn. In this study, the S. rostrata PCS gene (SrPCS) and cDNAs were isolated and characterized. Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1–SrPCS4, by alternative splicing of the SrPCS pre-mRNA. The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not. These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils.     

Analysis of plane failures in compound slopes

ABSTRACT

Plane failure in rock and soil slopes is usually caused by the intersection of a discontinuity plane with a slope face. This discontinuity can be any one of many different types of faulting, fracturing, bedding, foliation, schistosity, etc. Generally, these discontinuities are weaker than the surrounding intact material and provide a surface along which movement can occur.

When designing a stable slope, it is often desirable to find the worst conditions for a particular slope configuration and base the final design around those conditions. The worst case for most dry slopes usually includes a tension crack at an unknown location. This paper focuses on plane failure analyses of compound slopes using limit equilibrium techniques. It provides new equations to calculate the position of tension cracks in compound slopes.     

不同添加剂对大白菜吸收铜的影响

研究了几种不同的化合物如草酸、酒石酸、EDTA、KCl、NH4Cl、MgCl2、CaCl2 和FeCl3作为添加剂对大白菜吸收铜的影响。结果表明,施用各种添加剂都可增加大白菜体内铜浓度,且随着投加的各种添加剂的浓度的增加而增加,其中EDTA和FeCl3 >草酸、NH4Cl和MgCl2 >酒石酸>KCl和CaCl2。而根冠比(茎叶中的Cu含量与根系中Cu含量的比值),其中以FeCl3最高,其次为草酸。     

Microradiography as a tool to detect heavy metal uptake in plants for phytoremediation applications

In this paper, an application of contact microradiography with soft X-rays for detecting the uptake site of heavy metal in the whole plant leaves is investigated. The X-ray source is a laser-plasma one based on an Nd:glass laser. The soft X-ray radiation emitted from the plasma laser targets of magnesium, iron, and copper can be strongly absorbed in the leaves' regions rich in iron, magnesium, and copper. This absorbance could point to structures in the leaves where these heavy elements are found. In this work, leaves treated with copper sulfate diluted in water at 1, 2, and 5% were imaged by using a copper target, in order to evaluate differences with untreated control leaves. Our results showed that this methodology highlighted the presence of copper in the treated leaves. This new methodology should detect heavy element pollutants inside plants and it should also be a useful analytic tool in phytoremediation studies.     

水中MTBE污染治理技术研究进展

甲基叔丁基醚(MTBE)作为高辛烷值的汽油调和组分被广泛使用。但MTBE本身是一种潜在的环境污染物,在储存、运输和使用过程中泄漏到环境中的MTBE会对水体造成污染。综述了国内外有关水中MTBE的污染治理技术,主要有吸附、高级氧化、微生物降解、植物转移修复等技术。吸附用吸附剂主要有活性炭、沸石、树脂等;高级氧化法主要包括催化氧化、H_2O_2氧化、O_3氧化、Fenton氧化、电化学氧化等;微生物降解有好氧降解和厌氧降解。     

土壤重金属污染的植物修复机理研究概述

植物修复方法具有诸多优点,是一种治理土壤重金属污染的理想措施,但该种方法也存在某些方面的限制因素．在参阅大量国内外研究资料的基础上,通过介绍一些成功的修复案例,系统分析了植物修复的特点、机理、限制因素等方面,并对当前实用性较强的植物．微生物联合修复技术进行了探讨,在此基础上表述了自身的观点,从而为该领域的研究提供一些理论参考．     

覆膜对油菜修复铅污染土壤影响研究

通过不同铅含量土壤上的覆膜油菜微区试验,分析了覆膜对油菜修复铅污染土壤的影响。结果表明：覆膜条件下油菜叶片和根部的铅含量随着生长期的延长而增加。在同一生长时期,油菜叶片和根部的铅含量随着土壤铅添加量的增大而增加。覆膜条件下不同铅浓度处理土壤油菜叶片和根部的铅含量均大于不覆膜处理,且施铅浓度越大,影响越明显;油菜叶片和根部铅含量越大,油菜鲜重越小。     

柠檬酸对黑麦草修复铀污染土壤的影响

为探究柠檬酸浓度对黑麦草修复铀污染土壤的效率及其生理特性的影响,通过盆栽试验,研究了15 mg/kg铀胁迫下不同浓度（0、1、5、10 mmol/kg）柠檬酸对黑麦草生长、生理及重金属积累与分布的影响。结果表明：相同浓度铀胁迫下,随柠檬酸浓度的升高,黑麦草长势、光合色素、可溶性蛋白含量、根系活力、还原型谷胱甘肽（GSH）及几种酶(过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽还原酶（GR）)的活性呈先升后降的趋势;黑麦草根叶质膜透性、丙二醛（MDA）含量及氧化型谷胱甘肽（GSSG）含量逐渐上升;黑麦草对铀的富集量呈先升后降的趋势,但均表现为根部富集量高于地上部分;亚细胞分布中,铀的富集量为细胞壁及残渣部分＞可溶性部分＞细胞器及膜部分,且各部分铀含量均先增后降。透射电镜结果显示,铀胁迫对黑麦草超微结构造成了不可逆伤害,添加5 mmol/kg柠檬酸,损伤程度得以减轻。以上结果表明,低浓度（1、5 mmol/kg）柠檬酸可促进黑麦草在铀污染土壤中的生长,增强黑麦草对铀污染土壤的修复效率,其中5 mmol/kg柠檬酸的施加效果最佳,而10 mmol/kg柠檬酸则会抑制黑麦草生长。