导　　师： 周晓阳

学科专业： G1001

授予学位： 硕士

作　　者： ;

机构地区： 北京林业大学

摘　　要： 植物细胞中Ca2+起着维持离子平衡、水分平衡和构成细胞保护体系的作用,并被认为是细胞最重要的第二信使；Ca2+-ATPase在保持正常细胞胞质Ca2+浓度平衡、提高植物抗逆性、维持细胞在逆境中的正常生长等方面起着重要的生理作用。逆境引发的刺激信号传入细胞中时,不同植物不同器官的细胞、以及细胞内不同细胞器中Ca2+及Ca2+-ATPase水平出现差异性变化,深入研究此变化机制,是指导实践工作的前提。 根据胡杨和意大利杨同属木本植物、却在抗逆性方面具有较大差异的特点,本实验选此二种植物作为实验材料,并均采用相同时间和强度的盐胁迫和干旱胁迫处理,借助X射线能谱分析技术和硝酸铅沉淀的电镜细胞化学法,定性、定量进行数据的分析及谱图绘制工作,以期通过对实验结果进行对比,达到研究外界刺激引发的抗性不同的植物细胞以及不同细胞器内Ca2+水平和Ca2+-ATPase水平的变化,以及它们的变化对植物细胞生理生化方面的影响。 实验结果表明,胡杨抗逆性较强,在整个实验过程中其细胞Ca2+-ATPase一直高于同期处理的意大利杨细胞。另外,短期干旱和盐的刺激,还会促使Ca2+-ATPase的活性短暂升高,但随时间延长、逆境强度加大,其活性随即持续转小；意大利杨细胞Ca2+-ATPase活性则随时间延长呈现同一趋势,即其活性不断减小。另一方面,低温、干旱、高盐渗透等逆境胁迫刺激Ca2+在细胞内进行了重新分布和定位：在静息态的植物细胞中,胞质Ca2+含量极微；干旱和盐胁迫对胡杨和意大利杨的细胞均产生相似的刺激效应,即促使Ca2+由钙库/(主要是液泡/)流出至胞质,增大胞质Ca2+浓度。细胞中Ca2+的感受蛋白随即活化,引发下游磷酸化反应进行响应,一定程度内缓解逆境伤害。但在刺激强度较大时,随着胡杨与意大利杨的Ca2+-ATPase活性均降至极低,细胞质沉积过多的Ca2+引起细胞中毒,并诱导凋亡,最后植株死亡。 Ca2+plays roles in sustaining the balance level of the ion and the water in plant cells, and it's a component part of cell's protective system as well as the most important second messenger in plant cells; Ca2+-ATPase plays significant roles in keeping the concentration of Ca2+balanceable in cytoplasm, improving plant cell's performance of stress tolerance and keeping cells alive and active under various stress in a certain degree. The stress induce some kind of signal which will be transferrsd into cells, then some certain actions such as Ca2+and Ca2+-ATPase will be taken place,which will response to the corresponding external circumstance. That process is various according to different organs of a plant as well as different organelles of a cell. So studying this mechanism will assure our scientific practice. Both Populus euphratica and P.euramericana are ligneous plant, whereas they have adverse tolerances to stress. According to this we have chosen them as materials,aiming to analyze and compare them under the same treat—drought and salinity. We take advantages of X-ray technology and electron microscop-cytochemical method to analyze the energy spectrum and the location of sedimentation in both quality and quantity aspects,which is extremely helpful to study the effect of Ca2+and Ca2+-ATPase in plants. The experimental has revealed that Ca2+level of both polar decreased with the strengthening of stress in vacuole,yet is adverse in cytoplasm.The activity of Ca2+-ATPase in plasma membrane and tonoplast of the two polar are different under drought and saline stress.It's always more activated in Populus euphratica,although it has decreased a lot after a temporary increase in the first 16 days. While to P.euramericana,it lasted decreaseing with the intensity of stress.

关 键 词： 盐胁迫 干旱胁迫

分 类 号： [S79 S76]

领　　域： [农业科学] [农业科学] [农业科学] [农业科学]