植物对金属离子胁迫的响应机制研究
杨慧
学位类型硕士
导师李唯奇
2010-11
学位授予单位中国科学院研究生院
学位专业生物化学与分子生物学
摘要随着人类生产的发展,环境染污问题日趋严重。金属离子污染,特别是重金属离子的染污,通过作物吸收积累的生物学过程,严重威胁食品安全;通过影响植物的生长,造成生态问题。研究植物对金属离子胁迫的响应具有重要的科学意义和应用价值。本文以拟南芥及其突变体和油菜为主要研究对象,第一部分,通过检测叶片渗透调节物的变化与金属离子的电荷和半径之间的关系,研究植物根部对金属离子胁迫的响应机制,在植株水平上研究植物对金属离子胁迫的响应;第二部分,通过检测叶片和根部细胞膜脂分子变化,研究植物细胞膜脂对金属离子胁迫的响应机制,在细胞水平上研究植物对金属离子胁迫的响应。第一部分的主要结果如下:1、金属离子对周围分子的作用主要取决于其半径、电荷和及电子层结构。根据元素周期表,选择了离子电荷、半径和电子层结构不同的16种金属离子进行研究。金属离子胁迫的设置是,在水培体系中加入金属离子,通过根系处理拟南芥和油菜。我们发现随着金属离子浓度的提高,植物叶片的电解质渗漏在增加;半径大的金属离子导致的植物的50%渗漏高,例如,Ca2+胁迫电导率值最大,其次分别是K+ 、Na+ 、Mg2+;而半径小的重金属离子如Cu2+ 、Cd2+ 、Zn2+ 、Hg2+ 等导致金属离子胁迫拟南芥的50%渗漏相对最低;而稀有金属元素Ce3+胁迫的50%渗漏值则介于两者之间。上述证据说明金属离子的胁迫能力与其半径成相反的关系,与金属离子的电荷成正向的关系。综合起来,金属离子产生的胁迫能力与其离子势(电荷/半径)成正相关。2、植物在胁迫下积累渗透调节物脯氨酸和产生膜脂过氧化产物丙二醛。我们发现,相同浓度的碱金属离子Li+、Na+及K+处理拟南芥野生型及油菜后,离子半径小的Li+能诱导植物产生更多的游离脯氨酸与丙二醛;相同浓度的Na+ 、Mg2+及Al3+胁迫拟南芥野生型与油菜,带电荷多的Al3+能诱导植物产生更多的游离脯氨酸与丙二醛;相同浓度的Ca2+、Al3+及Fe3+胁迫,Fe3+能诱导拟南芥与油菜产生更多的游离脯氨酸与丙二醛。上述证据说明,植物积累脯氨酸和产生丙二醛与金属离子半径成相反关系、与金属离子电荷成正向关系。金属离子电子层结构的复杂性也影响脯氨酸和丙二醛的产生。综合起来,植物响应金属离子胁迫的程度与金属的离子势(电荷/半径)正相关。膜脂过氧化物丙二醛含量与金属离子也呈现类似的关系。3、植物的离体叶片在金属离子的处理下,也能积累脯氨酸。但是,我们发现离体叶片中脯氨酸的积累与金属离子的电荷和半径不相关。这说明植物对金属离子的感应是通过根系进行的。而不是直接的细胞感应渗透胁迫的结果。4、为了进一步验证植物的根系能够感应金属离子的胁迫,我们对植物的根系进行了伤害处理,观察在根系受到伤害情况下,金属离子对植物积累脯氨酸的影响。发现热激植物的根系,不影响金属离子与脯氨酸积累的关系;但是机械方法剪去部分植物的根系,金属离子处理较长时间也不影响金属离子诱导的脯氨酸积累。上述证据说明,植物通过根响应金属离子的过程是复杂的,如何定量描述这个影响还需要进一步实验。5、植物中脯氨酸的生物合成的关键酶是P5CS。我们比较了拟南芥野生型和P5CS缺失型突变体对金属离子胁迫的响应,发现金属离子诱导的脯氨酸积累在突变体中显著减少了。说明金属离子诱导植物脯氨酸产生可能主要是通过提高其合成而不是减少其降解而产生的。第二部分的主要结果如下:细胞膜是细胞感应环境的主要器官,细胞可以通过膜脂组成的变化响应环境的变化。环境中金属离子影响是普遍现象,金属离子性质是如何影响植物细胞膜的变化是一个重要问题,但是其变化规律尚且未知。我们在相同金属离子胁迫强度(50%电解质渗漏值)下,利用脂类组学方法,比较了7种离子半径、电荷和电子层结构不同的金属离子(Li+,Pb2+,Cu2+,Zn2+,Co2+,Fe3+ 与Cd2+)对植物地上部分和地下部分细胞膜脂的影响。我们获得了海量的脂类数据,在有限的时间下进行了初步分析,即发现了金属离子对膜脂分子的影响有多种表现。深入系统的数据挖掘工作还在进行中,下面给出两个例子:1、Li+, Pb2+,Cu2+,Zn2+与Co2+分别胁迫拟南芥5天后,根中溶血磷脂分子的相对含量没有明显的变化,而叶片中的溶血磷脂分子却均有不同程度的升高。这说明,植物的根与叶片对金属离子的响应机制可能不同,分别是一个直接与间接响应逆境的过程。2、Fe3+与Cd2+都是离子势很强的金属离子。我们发现,Fe3+胁迫拟南芥12小时后,根中LysoPC等分子上升了上百倍,而在相同离子强度(50%电解质渗漏值)Cd2+胁迫下,该分子却没有发生明显的变化。这说明,植物膜脂分子对不同金属离子的响应机制不同,这主要与金属的性质等有关系。
资助项目With the industrial production of human development, environmental pollution problems have become more serious. Metal ion pollution, especially pollution of heavy metal ions, through the biological processes of crop uptaking and accumulation, causing a serious threat to food security; by affecting plant growth, resulting in ecological problems. Plants response to metal ion stress has an important scientific significance and application value. In this study, we used Columbia ecotype, mutants of Arabidopsis thaliana and Brassica napus as materials, the first part, by detecting the relationship between the changes of osmotic adjustment and the charge (or the radius) of metal ions in leaves, we explored the mechanisms of plant roots response to metal ion stress, in order to research the plants response to metal ion stress at the plant level; the second part, by detecting the changes of membrane lipid molecules in leaves and roots, we studyed the mechanism of plant cell membrane response to metal ion stress, so as to explore the plants response to metal ion stress at the cell level.The main results of the first part are as below: 1. Metal ion has effects on the surrounding molecules depends on its radius, the charge and the structure of electron shell. According to the periodic table, we selected 16 kinds of metal ions with different ionic charge, radius and electron shell structure in research. The setting of the metal ion stress was water culture system with adding metal ions, and we studyed the plants response to metal ions through the roots of and Arabidopsis thaliana and Brassica napus.We found that as the concentration of metal ion increased, the relative leakage of the leaves also increased; and the metal ion which had bigger radius resulted in bigger 50% relative leakage, such as Ca2+ stresses resulted in the biggest 50% relative leakage, K+, Na+ and Mg2+ as follows; and heavy metal ions such as Cu2+, Cd2+, Zn2+ and Hg2+ resulted in the smallest 50% relative leakage of all; and the 50% relative leakage of scarce metals Ce3+ was between them. The evidence above suggested that the relationship between the stress capacity of metal ions and its radius was inverse, and the charge of metal ions was positive, respectively. Above all, the relationship between the stress capacity of metal ions and their ionic potential (ionic charge / radius) was positive. 2. Plants could accumulate Osmo regulation substances and produce lipid peroxidation product malondialdehyde after stress condition. We found that after the same concentration of alkali metal Li+, Na+ and K+ stressed Arabidopsis thaliana and Brassica napus, Li+ stress induced the most free proline and MDA production, and the ion radius of which is the smallest; and after the same concentration of Na+, Mg2+ and Al3+ stress Arabidopsis thaliana and Brassica napus, Al3+ stress induced the most free proline and MDA production, and the ion charge of which was the most; and after the same concentration of Ca2+, Al3+and Fe3+ stress Arabidopsis thaliana and Brassica napus, Fe3+ stress induced the most free proline and MDA production. The evidence above suggested that the relationship between the capacity of proline accumulation and MDA and its radius was inverse, and the charge of metal ions was positive, respectively. Above all, the the relationship between the stress capacity of metal ions and their ionic potential (ionic charge/radius) was positive. Besides, the relationship between the production of MDA and metal ion was similar. 3. Detached leaves of plants with the metal ion treatment also accumulated proline. However, we found that the proline accumulation in the detached leaves had no relationship with the radius and the ionic charge of metal. This showed that the plants response to metal ions was conducted through the root system, rather than a direct result of cells responsed to osmotic stress. 4. To further verify the plant's root system could sense the metal ions stress, we damaged the root of the plant to observe that metal ions had effects on the proline accumulation in the case of the injury. And we found that root with heat stress had no effect on the relationship between the metal ions and proline accumulation. However, mechanically cutting the root even part of the root of the plants, then exposured to hydroponic culture with the metal ions 5 day, we found that there was no significant diffierence between them. The evidence above suggested that the plants responsed to metal ions conducted through roots are complex, and how to quantify this effect required our futher experiment. 5. P5CS is the key enzyme in proline biothesis in plants. We compared wild-type and P5CS deficient mutants of Arabidopsis responsed to metal ion stress, and found that compared to Columbia ecotype of Arabidopsis thaliana, knockout mutations of P5CS1 resulted in less free proline production under the same stress condition. This suggested that metal ions induced proline production by increasing its synthesis rather than reducing degradation. The main results of the second part are as below: The main organs sensing the environment is cell membrane, and cells can respond to changes through the changes of membrane lipids composition in the environment. It is a common phenomenon that environmental metal ions have effects on the plants, and how to impact the changes of the lipids is a significant question, and so far, we have no idea about this. In the same stress intensity (the value of 50% relative leakage), we use of lipid genomics approaches, and comparedthe effects of 7 metal ions (Li+,Pb2+,Cu2+,Zn2+,Co2+,Fe3+ and Cd2+) with different ionic radius, charge and the electron shell structure on the cell membrane lipids of aboveground and underground parts of plants. Because of the limited time, we did preliminary analysis from the mass of lipid data. We found that effects of the metal ions on the membrane lipid molecules have a variety of performances. And data analysis is working, two examples were as follows: 1. After Li+,Pb2+,Cu2+,Zn2+ and Co2+stressed Arabidopsis thaliana for 5days, there was no significant changes in Lysophosphlipids of roots, however, the lysophospholipid molecules of leaves increased in different degrees.The evidence above indicated that the mechanisms of roots and leaves responsed to metal ions maybe different, they were direct and indirect process, respectively. 2. Fe3+ and Cd2+ are two metal ions with lager ionic potential. We found that after Fe3+ and Cd2+ stressed Arabidopsis thaliana for 12 hours, the LysoPC in roots increased more than houdred times, but Cd2+ with the same stress intensity (the value of 50% relative leakage) had no effect on the LysoPC, almostly. The evidence above suggested that the mechanisms of membrane lipids responsed to different metal ions different, and this mainly had relationship with the characters of metal ions and so on.
语种ch
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16044
专题昆明植物所硕博研究生毕业学位论文
推荐引用方式
GB/T 7714
杨慧. 植物对金属离子胁迫的响应机制研究[D]. 中国科学院研究生院,2010.
条目包含的文件
文件名称/大小 文献类型 版本类型 开放类型 使用许可
杨慧.pdf(3018KB) 限制开放--请求全文
个性服务
推荐该条目
保存到收藏夹
查看访问统计
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[杨慧]的文章
百度学术
百度学术中相似的文章
[杨慧]的文章
必应学术
必应学术中相似的文章
[杨慧]的文章
相关权益政策
暂无数据
收藏/分享
所有评论 (0)
暂无评论
 

除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。