植物响应三种典型非生物胁迫的机制解析
郑国伟
学位类型博士
导师李唯奇
2010-05
学位授予单位中国科学院研究生院
学位专业植物学
摘要逆境会对植物的生存、生长及繁衍造成有害的影响,非生物逆境主要是指极端温度、干旱、洪涝、盐碱、辐照、化学物质等对植物生长发育产生有害影响的环境因子,研究植物对非生物逆境的响应机制,并用其指导农业生产是当前热点研究领域之一。膜是最灵敏的环境感应器管,细胞主要通过膜脂分子和膜蛋白的变化感应和转导环境信号。维持细胞膜的完整性和保持其功能是植物抗逆的首要事件。通过调节膜蛋白磷脂酶D(phospholipase D, PLD)活性及改变膜脂分子组成及含量是植物抗逆的重要手段。研究发现,对于冷冻、冻融、种子老化、脱水等非生物胁迫,植物主要通过改变膜脂分子特别是信使分子磷脂酸PA的变化来响应;而磷脂酶D的突变体可以提高植物对这些胁迫的抗性。研究逆境下膜脂分子及膜蛋白的变化规律及其作用是当前研究逆境的最重要方面。对于我们研究的三种非生物逆境(高山流石滩冷热快速变化胁迫、化感胁迫及Gamma辐照胁迫)下,植物如何改变膜系统来响应这些胁迫的,磷脂酶D的突变体是否对这些胁迫有独特的抗性呢?我们通过表征这三种胁迫下细胞膜脂11种脂类160种脂分子的变化,探索膜脂在这些胁迫中的变化规律;同时通过利用磷脂酶D突变体研究了磷脂酶D在植物响应这些胁迫中的作用。植物对胁迫的响应不是一个简单的过程,我们还研究了这些胁迫下的代谢物及激素的变化规律,具体的研究内容如下:滇西北高山流石滩一天内具有“昼暑夜寒”现象,日最高温差达35 °C-40 °C。我们研究发现,生长在该生境的植物水母雪兔子(Saussurea medusa)及线叶丛菔(Solms-Laubachia linearifolia)叶片中的膜脂组成及含量随一天内温度的变化呈现一定规律的波动,但是与温度密切相关的脂饱和度却没有明显变化,同时和胁迫相关的溶血磷脂增加很少。我们通过室内模拟冷热快速长期变化处理高山植物须弥芥及模式植物拟南芥证实了高山发现的规律:对于长期的一天内冷热快速变化循环,植物的膜主要通过改变膜上各不同脂类分子的含量来响应该变化,而脂类的饱和度变化不大。我们认为,植物在长期的生长过程中,已经适应了冷热一天内快速变化,高山植物与室内模拟实验都证实膜脂对该温度变化是一种适应性的反应并非胁迫响应。紫茎泽兰作为危害最大的入侵植物,研究其入侵机制非常必要。通过植物化学分离分析方法得到化合物(这部分工作由赵旭完成)再对化合物毒性进行分析,我们发现紫茎泽兰中含量丰富(10 Kg鲜重得到1 g)的邻羟基桂皮酸(o-Hydroxycinnamic acid,o-HCA)具有强的抑制拟南芥种子萌发的作用,而它的另外两种异构体(m-HCA, p-HCA)则对种子萌发没有抑制作用。o-HCA还可以诱导拟南芥根细胞的死亡,抑制拟南芥幼苗的生长,甚至导致幼苗的死亡。我们认为通过诱导根细胞死亡,从而导致植物对水分及营养物质的吸收受阻,进而导致植物的死亡,这个可能就是o-HCA的胁迫机制。同时,o-HCA也可以抑制紫茎泽兰种子的萌发,但是对幼苗生长没有影响。由于紫茎泽兰的特性(种子量大,可以进行营养繁殖)使得它可以将o-HCA的毒害作用降到最低,而入侵地的植物受到o-HCA的胁迫后就不能很好的生长,甚至死亡,从而使紫茎泽兰占据较好的生态位,成功入侵。同时,我们还对报道的入侵北美的植物矢车菊释放的化感物质catechin对拟南芥膜脂组成的影响进行了研究。我们发现,野生型和磷脂酶Dd敲除型突变体在catechin胁迫下没有表现出明显的差异,两种拟南芥在catechin胁迫下膜脂没有表现出显著的不同。Gamma辐照通常用来诱变植物,贮藏水果蔬菜、药物的灭菌等,但是人们对Gamma辐照中植物膜脂分子的变化尚且未知。通过Gamma射线辐照胁迫拟南芥,我们找到了抑制拟南芥植株生长的剂量(50-100 Gy)及抑制植株开花的剂量(高于200 Gy)。通过这些剂量处理拟南芥,发现野生型拟南芥与磷脂酶Da1反义抑制及Dd敲除型突变体在Gamma辐照胁迫下没有表现出明显的差异。Gamma辐照导致了拟南芥膜脂的降解,其中MGDG、DGDG降解最为严重,但是并没有导致膜脂碳链的断裂。辐照下,膜脂的绝对含量(nmol per mg dry weight)下降幅度很大,而相对含量(mol% of total)变化趋势完全相反且幅度较小。膜脂相对含量的稳定可能对于膜的稳定性有重要意义。膜脂分子在Gamma辐射中显现了独特的变化规律,与在温度、水分和盐碱中的情况不同。辐照还导致了幼苗中代谢物的明显变化,同时四种激素(ABA,ZR,JA,IAA)在不同剂量处理下及处理后不同时间的含量变化很大。
资助项目Environmental stresses could limit plant growth, development and propagation. Abiotic stress refers to the negative impact factors to the plants, such as extreme temperature, drought, flood, salinity, irradiation, chemicals and so on. To understand the mechanism of abiotic stress is very important.Membrane is the most sensitive organs in the cell that response to environmental changes. Cells respond and transduct environmental signals by changing content of membrane lipids and membrane proteins. The activity change of membrane phospholipase D (PLD) and the composition and content of membrane lipid molecules is one of the most anti-stress methods for the plants. It was reported that plants responded to some abiotic stresses such as freezing, thawing, seed aging and dehydration through changing lipid molecules especially the messenger phosphatidic acid (PA) and mutants of PLD were more tolerant to those stresses. It is important to investigate the characteristics and variation of membrane lipids and membrane proteins to understand the streee in plants.Three different kinds of stresses, including alpine scree temperature stress, allelopathy and Gamma irradiation stress, were studied in the present dissertation. And try to understand how plants response to those stresses by changing membrane system and the function of PLD in resistant to those stresses, lipidomic methods were used to profiling the changing of 11 lipids classes (160 lipids molecules) under thoses stresses. Moreover, PLD mutants were also used to study the role of PLD under those stresses. The mechanisms of plants response to stresses were very complicated; PLD and lipid molecules were not the only factors that response to stresses, the metabolism and phytohormones of tested plants under these stresses were also studied.In alpine scree of northwest Yunnan, the temperature was various from 33 °C during the midday to 4 °C at night, and the highest temperature could reach to 35 to 40 °C. Saussurea medusa and Solms-Laubachia linearifolia, which live in this environment, were chosen as studied model. The results showed that membrane lipid of these two plants significantly fluctuated with the temperature, while the double bond index (DBI) that had close relationship to temperature did not change. Furthermore, the the lysolipids which rise significantly under stresses did not change too much either. Laboratory mimic experiments also confermed the characteristics of lipids change to temperature in alpine scree plants. The results suggested that the plants living in such temperature changeable environment had already adapted to this situation and their membrane responded to the temperature was a kind of adaptation instead of stress response.Since the first introduction in Yunnan province of China in 1940s, E. adenophorum has spread very rapidly especially in southwestern China. Without understanding its invasive mechanism, it is impossible to control it. o-Hydroxycinnamic acid (o-HCA), an allelochmeical isolated from leachates of aerial parts of E. adenophorum were studied. o-HCA was abundant in aerial parts of E. adenophorum (1g/10kg fresh weight). The data showed that o-HCA not only had strong allelopathic effect on Arabidopsis seeds germination, but also inhibited seedling growth, and even induced root death of Arabidopsis seedlings. It could be proposed that o-HCA affected seedlings indirectly, through inducing root cell death, and it disturbed the water and ion absorption of plants and finally induced seedling to die. Interestingly, o-HCA could also inhibit E. adenophorum seed germination, while it showed no effect on its seedling growth. E. adenophorum can produce thousands of seeds and has the ability to vegetative reproduction, with which may alleviate the harmful effect of o-HCA on E. adenophorum. Unlike E. adenophorum, its neighbors’ population was inhibited, under this situation, E. adenophorum coule have better condition to live and invade successfully.Arabidopsis were irradiated with gamma rays, and 50-100 Gy gamma irradiation could inhibit seedling growth, and with the dosage above 200 Gy it could inhibit seedling flowering. Treated Arabidopsis wild types and their PLD a and d mutant with gamma ray showed no significant differences among them. The lipid molecules changes of seedlings under stress of gamma ray were also tested, and found that Gamama ray induced lipids degradation, among which, MGDG and DGDG degraded dramatically, while the average carbons in lipids did not changed. The lipids content (nmol per mg dry weight) decreased significantly, while the mol% content (mol% of total) changed slightly. Gamma irradiation also leaded to dramatically change of Arabidopsis seedling metabolomics and the phytohormones (ABA,ZR,JA,IAA).
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16016
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
郑国伟. 植物响应三种典型非生物胁迫的机制解析[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
郑国伟.pdf(13956KB) 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
[郑国伟]的文章
百度学术
百度学术中相似的文章
[郑国伟]的文章
必应学术
必应学术中相似的文章
[郑国伟]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。