【作者】 庞玉建；

【导师】 宗浩；

【作者基本信息】 四川师范大学 ， 环境科学， 2009， 硕士

【摘要】 植物修复是国际上近年兴起的一门污染环境修复技术,它是以植物忍耐和超量积累某种或某些化学元素的理论为基础,利用植物及其共存微生物体系,清除环境中污染物的一门环境污染治理技术。植物修复技术能否成功实施的关键是如何筛选生物量大、对环境污染物富集能力强的积累植物和超积累植物。禾本科植物种类多,分布范围广,且多数植物具有较高的生物量。因此,有可能从禾本科植物中筛选出积累植物和超积累植物。本论文以广泛生长于铜矿区的禾本科植物狗牙根、苇状羊茅和百喜草为试验材料,运用砂培、土培等方法,研究它们对重金属吸收和积累性以及Cu、Zn胁迫条件下它们的生理生化特征,初步探讨它们在无机污染物污染土壤植物修复中的应用潜力。获得的主要研究结论如下:1.狗牙根、苇状羊茅和百喜草对Cu具有较强的耐性和蓄积能力。在染Cu环境中它们能正常生长。砂培条件下,这些植物能在7mg·L^-1Cu处理的营养液中生长并蓄积Cu。苇状羊茅根部含Cu量明显高于狗牙根和百喜草,前者平均含Cu量为4765.06±484.28mg·kg^-1,后两者分别为1749.23±154.95 mg·kg^-1、590.26±57.21 mg·kg^-1;茎叶部含Cu量也以苇状羊茅较高,平均为214.04±16.31mg·kg^-1,百喜草和狗牙根较低,分别为34.59±4.94mg·kg^-1、27.59±5.32 mg·kg^-1。土培试验也证实,狗牙根和百喜草具有蓄积Cu的能力,当它们生长于50 mg·kg^-1的染Cu土壤70天时,它们的根部可分别蓄积101.16±10.26、132.13±73.46mg·kg^-1Cu,茎叶部可分别蓄积22.09±1.06、29.72±17.38mg·kg^-1Cu。上述结果表明,三种禾本科植物均可作为植物修复铜污染土壤的先锋物种。2.狗牙根和百喜草可生长于Cu、Zn复合污染环境中并能蓄积一定量的Cu、Zn。虽然砂培Cu、Zn复合污染条件下狗牙根和百喜草根和茎叶部生物量明显低于Cu、Zn单一污染和对照,它们仍能正常生长于这种复合污染环境条件下,并表现出一定的蓄Cu、Zn能力。复合污染条件下,植物吸收Cu、Zn过程中Cu、Zn之间交互作用明显,狗牙根对Cu、Zn的吸收表现为相互抑制,百喜草器官中Cu、Zn含量分别比单独染Cu、单独染Zn时低,染Cu抑制百喜草对Zn的吸收,染Zn抑制百喜草对Cu的吸收。3.Cu、Zn污染可影响狗牙根和百喜草某些生理生化特征。砂培单独染Cu处理后,百喜草叶绿素含量明显降低,叶绿素确值显著增大,MDA的积累加快,SOD、POD活性增强,CAT活性出现短暂升高,但随着处理时间的增加CAT活性又呈现出下降的趋势。土培单独染Cu处理后狗牙根和百喜草生理生化特征的变化趋势与砂培单独染Cu处理基本一致。砂培Cu、Zn复合污染对狗牙根和百喜草生理生化特征的影响较单一污染时显著:复合污染时百喜草叶绿素含量、CAT活性明显低于单一污染,MDA含量、SOD、POD活性也较单一污染明显升高;与单一污染相比,复合污染也使狗牙根POD活性明显升高。更多还原

【Abstract】 Phytoremediation is an emerging environmental clean-up technique.It explores the nature with which plants can tolerate and hyperaccumulate some chemical elements,in combination with plant’s natural ability and its associated microorganisms to remove the contaminants in the environment.Screening accumulators or hyperaccumulators with large biomass and strong ability to take up environmental pollutants is the key for suceessful phytoremediation practices.Plant species from the Polygonaceae are widely distributed with most of them having large biomass,and it is,therefore,possible to screen accumulators and hyperaccumulators from the Polygonaceae.A batch of sand culture and soil culture experiments were carried out to investigate heavy metal uptake and accumulation by Rumexacetosa Linn,Polygonum microcephalum D.Don,and Rumex hastatus D.Don widely distributed on copper mining areas,and their physiological and biochemical characteristics under Cu、Zn stress,as well their potentials in application to phytoremediation.The major results were summarized as follows:1.Cynodondactylon,FestucaarundinaceaSchreb,and Paspalumnotatum were found to have comparatively strong ability to tolerate and accumulate copper and to maintain normal growth in Cu-contaminated environment.Sand culture experimental results show that they could survive in 7 mg·L^-1 Cu treated nutrient solution and accumulate copper to a certain extent.FestucaarundinaceaSchreb had higher root copper concentration than Cynodondactylon and Paspalumnotatum.The former has root copper concentrations averaging 4765.06±484.28 while the latter two have root copper concentrations averaging 1749.23±254.95 and 590.26±57.21mg·kg^-1 respectively.FestucaarundinaceaSchreb also had higher shoot copper concentration averaging 214.04±16.31 mg·kg^-1 than Paspalumnotatum and Cynodondactylon which contain average shoot copper concentration 27.59±5.32、34.59±4.94mg·kg^-1,respectively.Soil culture experiments also demonstrated that Cynodondactylon and Paspalumnotatum can accumulate some amount of copper with root copper concentration averaging101.16±10.26、132.13±73.46 mg·kg^-1,respectively and shoot copper concentration averaging 22.09±1.06、29.72±17.38 mg·kg^-1,respectively when grown for 70 days on soils contaminated with 50mg Cu·kg^-1.These results indicated that the three Gramineae can serve as pioneer species for phytoremediation of coppercontaminated soil.2.Cynodondactylon and Paspalumnotatum can in the contaminated with both Cu and Zn,and accumulate some amount of Cu and Zn.Although the combined treatments with both Cu and Zn decreased growth biomass compared with single Cu and single Zn treatments,they can also grow well in the combined polluted environment and accumulate certain amount of Cu and Zn.Under combined contamination,Cu and Zn showed obvious mutual interactions:Zn treatment decreased Cu uptake by Cynodondactylon and Paspalumnotatum,and Cu treatment depressed Zn uptake by Cynodondactylon and Paspalumnotatum.3.It is found that copper and zinc contamination has effect on some physiological and biochemieal characteristics of Cynodondactylon and Paspalumnotatum.Sand culture experimental results showed that the chlorophyll content of Paspalumnotatum grown in only copper treatment decreased but its chlorophyll a/b radio increased remarkably.It was also shown that single Cu treatment significantly enhaced MDA in Cynodondactylon and Paspalumnotatum leave cells,and increased the activity of SOD and POD,with CAT activity increasing at beging,and then decreasing With time.The soil pot experiment in single copper treatment showed similar variation characteristics of physiological and biochemical for Cynodondactylon and Paspalumnotatum.Under combined contamination physiological and biochemical characteristics of Cynodondactylon and Paspalumnotatum showed more rem-arkable variation than single treatment:Compared with single Cu and single Zn treatments,the cmbined treatments with both Cu and Zn decreased the chlorophyll content and CAT activity of Paspalumnotatum,while increased the root and leaf cell MDA content, SOD and POD activity of Paspalumnotatum,meanwhile the root and leaf cell POD activity of Cynodondactylon is also increased under combined contamination.更多还原