【作者】 李牡丹；

【导师】 高述民；

【作者基本信息】 北京林业大学 ， 植物学， 2008， 硕士

【摘要】 重金属污染已日益严重,铅是一种污染范围广、稳定不可降解的污染物,在环境中可长期积累。所以,植物在重金属Pb胁迫下的损伤与抗性机制研究已成为研究热点。本研究以禾本科植物芨芨草为试材,采用石蜡制片法、透射电子显微镜、同工酶电泳、蛋白质双向电泳等方法分析影响芨芨草抵抗Pb的重要因子,为选择修复重金属能力强的植物提供科学的依据。重金属Pb对芨芨草种子萌发有很大的抑制作用,对幼苗生长发育有不同程度的影响,表现为幼苗低矮、叶片失绿、根长度变短或不生长等特点。研究表明,Pb对芨芨草根皮层细胞有一定的影响,而淀粉粒有明显的积累。超显微结构显示,芨芨草细胞内细胞核、线粒体、叶绿体等细胞器受到伤害,而细胞壁的结合作用和液泡的区域化作用可缓解重金属毒害,从而使芨芨草能够进行正常的生理活动。芨芨草叶片的叶绿素、脯氨酸、丙二醛及可溶性总糖含量的测定结果表明:在Pb2+浓度为0mg·L-1-200 mg·L-1范围内,随Pb浓度上升各数值分别有明显的变化,各指标变化不同步。Pb对芨芨草叶绿素含量有极大的抑制作用;而脯氨酸则刚好相反,随Pb处理浓度升高,脯氨酸含量呈上升的趋势;丙二醛、可溶性总糖的含量最初都随浓度增加而逐渐增大,但随着Pb处理时间的延长、浓度的升高含量有所降低,160 mg·g-1是Pb处理芨芨草幼苗丙二醛、可溶性总糖含量升高的极限浓度。同工酶酶谱分析表明,过氧化物酶在Pb浓度为200 mg·L-1时仍能发挥巨大作用;在Pb浓度160 mg·L-1处淀粉酶活性最强; ATP酶抗重金属Pb总体活性也呈上升趋势。各酶抵抗Pb胁迫具有重要的作用。蛋白质双向电泳结果表明,蛋白点总数呈减少的趋势,其中3个蛋白点逐渐减弱至消失,9个蛋白点消失,9个新蛋白点出现,低分子量的蛋白在抵抗重金属Pb胁迫中发挥着重要的作用。上述结果均表明,不同浓度Pb处理下芨芨草出现了相应的胁迫生理反应,这种影响与Pb浓度及处理时间有一定的相关性。重金属对植物的毒害是对植物细胞生理活动和生化反应的整体伤害,是多种生理过程的综合反应。更多还原

【Abstract】 The pollution of heavy metals has now become more and more severe. Pb is a kind of contamination which is fargoing, stable, nondegradation and lasting accumulated.So the possible recovery mechanism of plants and the harm and resistance in the heavy metal Pb has become a recent hot research topic. Achnatherum splendens (Trin.) Nevskia as the main experimental material, the main factor of plant resisting heavy metal Pb was analyzed by using paraffin microtome section,transmission electron microscopy (TEM),gel electrophoresis of isozyme, and two-dimensional gel electrophoresis of total protein, it may offer for choosing plant which has strong capability of restore.The results showed that heavy metal Pb seriously inhabited seed germination of Achnatherum splendens (Trin.) Nevskia and affected seedling growth to various certain extents,it was showed that low seedlings, nongreen leaves , shorter root or can’t growing.Research indicates that cortex cell was affected by Pb stress ,starch grain accumulated evidently nevertheless.Ultrastructure showed Pb harmed to some organelles such as cell nucleus, mitochondria ,chloroplast.But combination of cell walls and separating of vacuoles relieved the harm of heavy metal,which made physiological activity of Achnatherum splendens (Trin.) Nevskia in a normal condition.Result of determination of some physiological indexes,such as chlorophyll,dissociated proline, malondialdehyde, soluble total sugar and isoenzyme were showed: all of these indexes changed as the concentration of Pb2+ solution increased evidently when the concentration was in 0mg·L-1-200 mg·L-1,each indexes was not changed at the same time.Pb stress restrain the content of chlorophyll of Achnatherum splendens (Trin.) Nevskia.Whereas,the content of dissociated proline elevated with the increased concentration of Pb2+. Malondialdehyde, soluble total sugar elevated with the concentration of Pb2+ solution increased at first, but the content of malondialdehyde and soluble total sugar reducing when the time going and the concentration elevating,then it reaching a utmost limit of their content when the concentration of Pb being 160 mg·g-1.Isoenzyme zymogram analysis showed POD was put into fullplay when the Pb concentration was in 200 mg·L-1.The activity of amylase was the most strong in 160 mg·L-1. The total anti-heavy metal activity of adenosinetriphosphatase has raised.Each enzyme played a great role for resisting Pb stress.The two-dimensional gel electrophoresis result of protein showed three spots disappearing gradually,nine ones disappearing and nine ones appearing in all of these spots.The protein which has low molecular weight palyed a important role for resisting Pb stress.Above results showed the corresponding physiological reacting of Achnatherum splendens (Trin.) Nevskia was appear in the different concentration of Pb2+.The effect and the concentration of Pb and disposal time are interrelated.Virus of plant by heavy metals is harm to the whole cell physiological activity and biochemistry reacting ,also the virus was the synthetized reacting of so many kinds of physiological process.更多还原