几种藓类植物对重金属胁迫的响应研究

【作者】 籍霞；

【导师】 衣艳君；

【作者基本信息】 曲阜师范大学 ， 植物学， 2010， 硕士

【摘要】 由于人类对重金属的开采、冶炼、加工及商业制造活动增多,造成不少重金属如铅、汞、镉、钴等进入大气、水、土壤中,使得环境中重金属污染物质负荷的日益增加。重金属污染具有隐蔽性、长期性、不可逆等特点,并可通过食物链影响人体健康,因而环境中重金属污染的监测与防治是城市环境保护中的重要课题之一。本实验选择了青岛崂山藓类植物配子体作为实验材料,研究了不同藓类植物富集重金属污染的能力,并通过对青岛崂山藓类植物的采集和室内重金属含量分析,比较了不同藓类植物对重金属元素的吸收积累、不同重金属在藓类植物体内的细胞分布特征以及重金属胁迫对藓类植物叶绿素荧光PSⅡ的影响,主要结果如下：1通过对2008、2009年青岛市崂山采集藓类植物体内重金属含量的比较研究,结果表明：(1)藓类植物是良好的环境质量的生物指示植物,可以指示环境重金属污染的现况,并可以用于对环境变化的长期监测。从崂山采集的藓类植物和土壤样品重金属含量来看,重金属元素Zn含量最高,而元素Cd含量最低,重金属元素Pb、Cu含量相近,2009年青岛环境中Pb、Cu的含量比2008年略有增加,但总体上青岛具有较好的空气质量。(2)不同藓类植物对重金属元素的富集能力不同,同种藓类植物对不同重金属的富集能力亦不相同,(3)不同种类的藓类植物对同一重金属元素的富集能力差异极其显著,毛尖紫萼藓Grimmia pilifera P.Beauv.和大灰藓Hypnum plumaeforme Wils.对环境中重金属有较强的积累能力,可作为指示植物监测重金属污染。石生生境下的藓类植物比土生生境下的积累重金属能力强,石生生境下的毛尖紫萼藓积累重金属能力最强。2研究了水灰藓Hygrphpnum eugyrium (B.S.G.) Broth.和波叶仙鹤藓Atrichum umdulatum(Hedw.)P.Beauv.对重金属Pb、Cd、Cu、Zn的吸收和积累特征,结果表明藓类植物对重金属离子的吸收积累可划分为二个阶段,即开始时的快速吸收积累阶段和之后的慢速吸收积累阶段。不同藓类植物对同一种重金属离子的吸附积累能力不同,同种藓类植物对不同重金属离子的吸附积累能力也不相同。藓类植物对重金属的吸附量随着处理液浓度的增加而增大。处理液浓度较低时,藓类植物对金属离子的吸附量也较低,随着处理液浓度的升高,吸附量增大。3研究了重金属Pb、Cd、Cu、Zn在水灰藓和波叶仙鹤藓细胞中的分布,结果表明藓类植物吸收的重金属以细胞外分布为主,细胞内可溶态以及结合态存在的重金属占比例较少,结合态的尤为少。但是不同重金属离子也存在差异,细胞中可溶态Cu、Zn占的比例远远大于Pb、Cd。4研究了水灰藓、波叶仙鹤藓以及大灰藓PSⅡ分别对单一重金属Pb、Cd、Cu、Zn胁迫下的响应,结果表明：(1)重金属胁迫对藓类植物的影响存在典型的剂量效应和时间效应,即随着处理浓度的增加以及处理时间的延长,各项荧光参数(Fv/Fm、ETo/ABS、ETo/TRo和RC/CSo均明显降低；(2)不同藓类植物对同一种重金属元素的耐受力不同,同种藓类植物对不同重金属元素的耐受性也不相同,波叶仙鹤藓相对于水灰藓、大灰藓对重金属Pb有较强的耐性,重金属Cd、Cu胁迫对三种藓类植物的光合机构均造成了明显的影响,其中Cd对水灰藓的影响最明显,Cu对波叶仙鹤藓的影响最大；(3)叶绿素荧光参数(Fv/Fm、ETo/ABS、ETo/TRo、RC/CSo)可以灵敏地反映出藓类植物对重金属胁迫的响应,可以快速反映出藓类植物对环境中重金属的忍耐程度。更多还原

【Abstract】 Many heavy metals like lead, mercury, cadmium, cobalt and so on enter in the atmosphere, the water, the soil because of heavy metal mining, smelting, processing and commercial manufactures. The heavy metal pollution have characteristics of confidentiality, permanence and irreversibility, and the human body health is affected through food chains. Therefore heavy metal pollution monitor and prevention is one of the most important topics of urban environment protection. In this paper, bryophyte gametophytes at Laoshan Mt. were selected as the experimental materials at Laoshan Mt. We studied the heavy metal enriching power and adsorption characteristic of the different bryophytes, cell distributed characteristic of different heavy metals and effect of heavy metal stress on chlorophyll fluorescence parameters in bryophyte. The results were listed as follows:1.Heavy metal content was researched between 2008 and 2009 in the bryophyte. The results indicated:(1)The bryophyte is the good indicator plant of environment quality, which not only shows the environment heavy metal pollution in the present situation, but also can be as a long-term monitor of environmental variation. Looking from the heavy metal content of bryophyte and soil at Laoshan, the heavy metal Zn content is the highest, the Cd content is the lowest, the Pb and the Cu content is close. The Pb and the Cu content in the environment in 2009 is more than that in 2008 at Laoshan. But as a whole, Qingdao has the good air quality.(2) Different species of bryophytes had different adsorptive ability to the same metal, and the same bryophyte had different adsorptive ability to the different heavy metals.(3)The difference of concentrates ability which different species of bryophyte has to the same metal is extremely remarkable. It is suggested that the moss Hypnum plumaeforme and Grimmia pilifera could be used as bioindicators in monitoring for the heavy metals pollution. The bryophyte of lithophilic habitat compared to locally born has the stronger accumulation ability. Grimmia pilifera ability is the strongest.2.Adsorption characteristic in two mosses Hygrphpnum eugyrium(B.S.G.) and Atrichum umdulatum(Hedw.)P.Beauv. to the stress caused by singed Pb, Cd, Cu and Zn have been investigated. The results indicated:the bryophytes’ adsorption dynamics to heavy metal could be carved into two stages, the rapid reaction phase and slow reaction phase. Different species of bryophytes had different adsorptive ability to the same metal, and the same bryophyte had different adsorptive ability to the different heavy metals. The capacity of the bryophytes adsorption to the heavy metal enhances along with the processing solution concentration increases.3.Cellular distributed characteristic in two mosses Hygrphpnum eugyrium(B.S.G.)and Atrichum umdulatum (Hedw.)P.Beauv. to the stress caused by singed Pb, Cd, Cu and Zn have been investigated. The results indicated:the massive heavy metals mainly distributed in the extracellular sites, and heavy metals of intracellular, especially particulate proportion are few. Cellular distributed characteristic were varied among different heavy metal species, indicating proportion is related to the heavy metal type.4.The response mechanisms of antioxidative systems in three mosses Hygrphpnum eugyrium (B.S.G.),Atrichum umdulatum(Hedw.)P.Beauv. and Hypnum plumaeforme Wils.to the stress caused by singed Pb,Cd,Cu and Zn have been investigated. The results indicated:(1)Heavy metals stress induced dose-dependent and time-dependent decline of chlorophyll fluorescence parameters in three mosses. (2) Different species of bryophytes had different tolerance to the same metal, and the same bryophyte had different tolerance to the different heavy metals. Atrichum umdulatum had a certain tolerance in Pb. The single heavy metal Cd and Cu had a more impact on photosynthesis in three mosses than the single heavy metal Pb and Zn.(3)The decline of their chlorophyll fluorescence parameters were related to the concentration of heavy metal and the processing time. Single Pb, Cd and Cu resulted in a decline of chlorophyll fluorescence parameters of Fv/Fm、ETo/TRo、RC/CSo and ETo/ABS.ETo/ABS and RC/CSo are more sensitive than other parameters, which may reflect the endurance of bryophyte under the heavy metal stress.更多还原