Viola baoshanensis, a plant that hyperaccumulates cadmium

This paper reports upon the finding of Viola baoshanensis, a cadmium (Cd) hyperaccumulator through field survey and greenhouse experiments. Average Cd concentration in the shoots and roots of V. baoshanensis growing on Baoshan lead/zinc mine in Hunan Province, China, was 1168 and 981 mg/kg, respectively, varying from 456 to 2310mg/kg in the shoots, and from 233 to 1846 mg/kg in the roots.The ratio of Cd concentration in shoot to root (DW) and that in plant shoots to total concentration in surface soil was 1.32 and 2.38, respectively. Under nutrient solution culture, biomass (DW) of V. baoshanensis exposed to 0-30 mg/L Cd insolution increased with Cd supply increasing and reached a maximum at 30 mg/L Cd. Further increase of Cd concentration (40, 50 mg/L) in solution significantly reduced biomass.Cd concentration in the shoots was positively correlated with Cd concentration in the culture medium. Cd concentration in the shoots reached 4825 mg/kg at 50 mg/L Cd solution. Theratio of Cd concentration of shoots to roots in V. baoshanensis was greater than 1 at all Cd treatments, with an average of 1.67 (1.14-2.22). The results indicate that V. baoshanensis is a Cd hyperaccumulator plant.     

镉污染土壤的植物修复研究进展与展望

近年来,重金属镉(Cd)及其复合污染问题越来越受到人们的关注.Cd污染土壤的植物修复技术因其具有治理成本的低廉性、环境美学的兼容性和治理过程的原位性等优势,随之成为具有广泛应用前景的技术.本文概述了Cd超积累植物的筛选及耐性机理与修复潜力的评价等方面的国内外进展,总结了Cd-重金属复合污染土壤、Cd-有机物复合污染土壤的植物修复相关的重要工作,着重评述了Cd复合污染土壤的化学强化、农业生态强化及其它方法的研发现状,展望了这一领域今后的重点研究内容和重要发展方向.     

Evidence of vacuolar compartmentalization of arsenic in the hyperaccumulator Pteris vittata

Pteris vittata can hyperaccumulate arsenic （As） to 〉1% of its dry weight without showing any signs of toxicity, indicating the existence of effective plant-internal detoxificaUon mechanisms. Although vacuolar compartmentalization is known to play an important role in heavy metal detoxification and tolerance, direct evidence of arsenic compartmentalization in this hyperaccumulator was lacking. Here we report the subcellular localization of As in the callus of P. vittata. The callus induced from gametophytes of P. vittata exposed to 0.2 mmol/L arsenate for 20 days were examined by directly isolating cell walls, protoplasts and vacuoles, and determining arsenic concentrations. Of the total As in the callus, about 94% was in the protoplast, and of that, 91% was present in the vacuoles, indicating that vacuoles are a major storage site for As in P. vittata. In addition, the changes in the chemical components of vacuoles were analyzed by Fourier transform infrared spectroscopy （FTIR）.     

Cellular distribution of arsenic and other elements in hyperaccumulator<Emphasis Type="Italic">Pteris nervosa</Emphasis> and their relations to arsenic accumulation

Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) was used to study the cellular distributions of arsenic and other elements in root, petiole, pinna of a newly discovered arsenic hyperaccumulator, Pteris nervosa. It was shown that there was a trend in P nervosa to transport arsenic from cortex tissue to vascular tissue in root, and keep arsenic in vascular during transportation in petiole, and transport arsenic from vascular tissue to adaxial cortex tissues in midrib of pinnae. More arsenic was accumulated in mesophyll than in epidermis in pinnae. The distributions of some elements, such as K, Ca, Mn, Fe, Cu, Zn, in petiole, midrib and pinna were similar to that of arsenic, indicating that those cations might cooperate with arsenic in those transportation processes; whereas the distributions of CI and Br in pinna were the reverse of that of arsenic, indicating that those anions might compete with arsenic in pinna of P. nervosa.     

重金属污染土壤的植物修复技术的研究进展

土壤重金属污染的植物修复是治理污染土壤的重要手段之一。本文对重金属污染土壤的植物修复的原理、类型与技术以及植物修复的特点进行了综合评价,并对该研究领域存在的问题和今后的研究与应用进行了简要的讨论。     

超积累植物在重金属污染土壤修复中的应用

重金属污染土壤植物修复技术是目前世界范围内研究的热点之一,超积累植物能超量吸收和积累土壤中的重金属元素,其体内重金属含量是一般植物的100倍以上,超积累植物修复是植物修复技术的关键。介绍了超积累植物的概念、特征、物种资源和开发现状,探讨了该技术的应用前景。     

Sedum alfredii H: A new Zn hyperaccumulating plant first found in China

Field survey and greenhouse experiments were carried out to identify and characterize zinc (Zn) uptake and accumulation by a new Zn hyperaccumulating plant species (Sedum alfredii Hance) native to China. Zinc concentration in the shoots of Sedum alfredii Hance grown on an ancient mined area ranged from 4134 to 5000 mg/kg, with a mean of 4515 mg/kg. It suggests that Sedum alfredii could not only grow on heavily Pb/Zn contaminated soils, but also could accumulate extraordinarily high concentration of Zn. Under nutrient solution culture conditions, Sedum alfredii Hance grew healthy at Zn supplying levels from 0.006 to 240 mg@L-1. Zinc concentration in the shoots increased with external Zn levels increasing. The Zn concentration and accumulation in the shoots reached the highest at Zn supply level of 80 mg/L, with 19.67 g/kg and 19.83 mg/plant, respectively. All the results showed that Sedum alfredii Hance is a new Zn hyperaccumulating plant. This provides a new plant material to explore mechanism of plant to hyperaccumulate Zn, and a potent new plant species to phytoremediate Zn contaminated soils.     

A newly-discovered Cd-hyperaccumulator Solanum nigrum L.

Phytoremediation emerged in early the 1980s is animportant technology for remedying contaminated sites.One of the most promising phytoremediation technologiesis phytoextraction using hyperaccumulators to removeheavy metals from contaminated soils. The ter…     

美洲商陆营养器官的解剖结构与其耐锰的关系

美洲商陆（Phytolacca acinosa Roxb）属于商陆科多年生草本植物,是一种适应性强的锰超积累植物．石蜡切片观察表明．美洲商陆经0．125、0．250、0．500和1．000g·kg^-1Mn^2＋处理7d后,根中柱的导管均变得发达．其中锰处理量为1．000g·kg^-1时,根表层细胞变得松散,茎内细胞内含物增加,叶片细胞内容物增加;当锰处理量大于0．250g·kg^-1时,海绵组织和栅栏组织变得松散,出现空隙．经0．125、0．250、0．500和1．000g·kg^-1Mn^2＋处理14d后．美洲商陆茎中的维管束数量迅速增加;根和叶片与处理7d的根和叶片比较结构变化不大．     

重金属超积累植物浅谈

阐述了重金属超积累植物的基本类别和概念。归纳总结了我国目前已发现的八种重金属超积累植物,并从全球已发现的500多种重金属超积累植物中浅析了其地域和科属分布特点。根据这些特征归纳出了三种常见的超积累植物找寻方法。