植物修复与超富集植物

本文回顾了我国尤其是珠三角地区重金属污染现状,总结了植物修复、超富集植物及当前研究热点问题。     

修复重金属污染土壤的超富集植物栽培措施研究进展*

 利用植物修复被重金属污染的土壤是当前国际学术界的热点研究领域。从超富集植物的品种选择、幼苗繁育、施肥(N,P肥和有机肥)、螯合剂和改良剂的使用、土壤水分条件、群落构建、采收时间等方面,系统地阐述了国内外关于超富集植物栽培措施的研究进展,提出了通过改善栽培措施,提高超富集植物地上部分生物量和重金属积累量的研究方向。     

植物修复重金属超标农田研究进展

针对中国南方重金属超标农田污染治理技术特点作了简要分析与探讨,并收集汇总中国现有镉、砷、铜和铅的超积累植物40种,同时进行了分类与归纳。依据中国现有的重金属超积累植物,讨论了中国南方重金属超标农田修复植物的筛选和培育方向,分别给出对重金属镉、砷、铜和铅的污染修复超积累植物应用建议及相关理论依据。     

重金属污染土壤的植物修复技术研究

植物修复重金属污染土壤已经成为当今科学家研究的热点问题。国内研究者已发表众多重金属污染土壤修复技术的文献综述,但单纯对重金属污染土壤的植物修复技术、特别是植物收获后的处置技术的系统综合的文献综述少之又少。为此,系统阐述了植物修复技术的内涵、组成部分、优缺点、超富集植物的概念、研究概况和修复植物收获后的处置技术,指出植物采矿技术可能成为科学家们下一步研究的重点,并对植物修复技术发展未来进行了展望。     

AM真菌提高宿主植物耐受重金属胁迫的生理机制

本文围绕重金属胁迫条件下丛枝菌根（AM）真菌的生理生态响应特征,从生理和分子水平上综述AM真菌对重金属离子吸收和控制的机理：1）AM真菌菌丝的吸附作用减缓重金属向植物地上部分的迁移,从而达到保护植物免受重金属毒害的目的;2）AM真菌的菌丝体分泌物与重金属之间的螯合作用;3）AM真菌促进宿主植物对矿质营养元素的吸收;4）调节重金属在宿主植物地上部分和地下部分的分布;5）AM真菌调节宿主植物体内抗氧化酶的活性和内源激素的水平;6）AM真菌调节参与吸收和转运重金属离子的基因的表达。综上所述,本文提出在广泛调查、筛选超累积菌根植物的基础上,不断探索植物－微生物－菌根复合体的修复机制,并结合基因工程技术,以促进重金属污染土壤的生物修复。     

Effect of hyperaccumulating plant cover composition and rhizosphere-associated bacteria on the efficiency of nickel extraction from soil

Most plant species selected as appropriate candidates for phytoextraction have been studied as monocultures. However, alternative cropping patterns which include rhizosphere microbial communities can significantly influence the extraction of metals, as well as soil protection and quality. Therefore, the objective of this work was to study the effect of species-rich vegetation cover, which consisted of three hyperaccumulator plant species, on the efficiency of nickel extraction from a naturally mineralized ultramafic soil. An experiment was set up with three hyperaccumulator species (Leptoplax emarginata, Noccaea tymphaea and Alyssum murale). Plants were cultivated separately (monospecific cover), or in combination (multispecies cover) in mesocosms under controlled conditions, on a nickel-rich ultramafic soil. Plants were grown for 92 days in controlled conditions. Each plant produced more biomass when grown in multispecies cover than alone. Noccaea and Alyssum showed the highest shoot Ni concentrations but Alyssum had by far the lowest shoot biomass. So, in this soil, Noccaea and Leptoplax have greater potential for hyperaccumulation than Alyssum. The amount of nickel accumulated in total biomass of Noccaea alone and of the multispecies cover was higher than that accumulated in either the monospecies Leptoplaxor Alyssum. Furthermore, the highest values of microbial biomass were obtained with the multispecies cover and a consistent production of auxin compounds by bacterial communities was measured, which emphasized the role of rhizosphere bacteria. The bacterial genetic structure also depended on the plant covers. A combination of the three species (multispecies cover), could be a good strategy for phytoremediation.     

土壤重金属污染下植物效应研究进展

文章综述了土壤重金属污染下植物的生理生态变化,并且对植物的重金属抗性机理研究进展进行了总结,探讨了以超富集植物为重点的植物修复技术的研究进展。     

土施镉超富集植物秸秆对镉胁迫牛膝菊光合特性的影响

通过在镉污染土壤中施用夏季生长的镉超富集植物红果黄鹌菜[Youngia erythrocarpa(Vaniot)Babcock et Stebbins]、三叶鬼针草(Bidens pilosa L.)、少花龙葵(Solanum photeinocarpum Nakamura et Odashima)和豨莶(Siegesbeckia orientalis L.)的秸秆,再种植秋冬季节生长的镉胁迫超富集植物牛膝菊(Galinsoga parviflora Cav.),研究了不同镉超富集植物秸秆对镉胁迫后牛膝菊光合特性的影响。结果表明,在土壤中施用红果黄鹌菜秸秆后,镉胁迫牛膝菊叶片的净光合速率较未施用秸秆的提高了4.29%,地上部生物量增加了7.33%,而施用三叶鬼针草、少花龙葵和豨莶秸秆的则降低了镉胁迫牛膝菊叶片净光合速率和地上部生物量。同时,土壤中施用红果黄鹌菜秸秆的镉胁迫牛膝菊叶片水分利用效率、光能利用率、胞间CO_2浓度、气孔导度和叶片表面蒸汽压亏缺等光合参数均较未施用秸秆的有所提高,蒸腾速率则较未施用秸秆的降低,而施用三叶鬼针草、少花龙葵和豨莶秸秆的光合参数则高低不同,可能是红果黄鹌菜秸秆的化感物质能提高镉胁迫牛膝菊的光合能力、促进牛膝菊的生长所致,而三叶鬼针草、少花龙葵和豨莶秸秆的化感物质则抑制了镉胁迫牛膝菊的光合能力与生长。就光合色素含量而言,只有施用红果黄鹌菜秸秆的镉胁迫牛膝菊叶片叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素含量较未施用秸秆的增加,分别较未施用秸秆的增加了5.97%、30.42%、10.94%和12.88%,施用三叶鬼针草、少花龙葵和豨莶秸秆的均低于未施用秸秆的。此外,土壤施用红果黄鹌菜秸秆的镉胁迫牛膝菊植株可溶性糖含量较未施用秸秆的增加。因此,在镉胁迫条件下,土壤施用红果黄鹌菜秸秆能够提高牛膝菊的光合能力,促进其生长,有利于牛膝菊修复镉污染的土壤。