【作者】 焦廷伟；

【导师】 郭素枝；

【作者基本信息】 福建农林大学 ， 细胞生物学， 2010， 硕士

【摘要】 本试验以醉香含笑(Michelia macclurei Dandy.)为试材,应用GC-MS、HPLC、光学显微镜、扫描电镜和透射电镜等技术,研究醉香含笑花被片在发育和衰老过程中细胞微观结构和若干生理生化指标的变化。研究结果如下:(1)激素变化与花被片衰老的关系醉香含笑花被片发育初期,IAA、GA3、Zt等延缓衰老的激素含量较高,调节了花被片的发育,此时促进衰老的ABA激素含量较低。随着花被片展开,延缓衰老激素和促进衰老激素含量都发生一些变化,IAA含量明显下降,而GA3、Zt含量略有增加,但总体含量还是比第Ⅰ时期减少。ETH的含量明显增加,花被片细胞衰老加剧而脱落。由此推测,ETH可能是花被片衰老的促进剂,而并非诱导剂。(2)抗氧化系统变化与衰老的关系随着醉香含笑花被片逐渐衰老,细胞合成酶能力呈逐渐降低的趋势,维生素C、总酚、类胡萝卜素等物质随之减少,细胞中抗氧化系统清除自由基的能力开始下降,对于细胞的保护能力也降低,最终导致细胞进入程序性死亡。因此,抗氧化系统的抗氧化能力下降在一定程度上促进了细胞衰老,但这并不是细胞衰老的诱导因素。(3)细胞内含物与细胞衰老的关系细胞内含物是花被片发育过程中的一种物质积累,这些物质的积累,影响和反映了细胞衰老的进程,MDA和脯氨酸的含量是衡量细胞衰老的指标之一。在花被片发育早期细胞中MDA和脯氨酸的含量较低,随着花被片的发育和展开,细胞中的MDA和脯氨酸含量逐渐升高。当花被片进入衰老后期,MDA和脯氨酸大量积累。而酚类等物质的消耗和降解也会降低细胞抗衰老的能力,超氧阴离子和过氧化氢含量的增加则严重破坏了细胞膜的稳定性,使细胞代谢环境失调,加剧了花被片衰老。(4)芳香物质变化与细胞衰老的关系醉香含笑花被片芳香物质种类繁多,共鉴定出37种化学成分,在花被片发育与衰老过程中的变化比较复杂。从醉香含笑花被片5个时期的检测结果来看,芳香物质种类的变化趋势由少→多→少,第Ⅳ时期检测到的种类和相对含量最高,第Ⅴ时期又减少。说明花被片从幼蕾生长至花蕾完全长大这一阶段,主要是合成并积累芳香物质的前体物,而从花被片展开至萎凋是香气散发、花被片细胞衰老凋亡的阶段。(5)细胞结构变化与衰老的关系通过组织化学染色发现,花被片薄壁细胞具有淀粉复合物。当花被片处于发育期时,在光学显微镜和扫描电镜下,薄壁细胞内淀粉复合物的体积和数量呈动态变化,其数量由少逐渐增多,体积由小变大。在透射电镜下,第Ⅱ时期至第Ⅲ时期花被片基本薄壁组织中淀粉复合物、线粒体、溶酶体等逐渐增多。随着花被片进入衰老期,薄壁细胞中淀粉复合物逐渐转化为香气物质被散发,其数量和体积即逐渐减少变小,甚至消失。电镜下观察到花被片表皮细胞塌陷、细胞间隙出现裂痕,细胞中的线粒体、溶酶体等细胞器出现不同程度解体,细胞壁严重弯曲、变形,花被片脱落萎凋。花被片发育过程中细胞结构的变化基本和细胞程序性死亡变化趋势一致。综合以上研究结果认为,花被片细胞结构以及生理生化的变化与细胞衰老的进程密切相关。更多还原

【Abstract】 In this paper, changes of physiology and biochemical and cell structure in the petal during development and aging process of Michelia macclurei were studied by using Gas Chromatography-Mass Spectrometer(GC-MS)、(High Performance Liquid Chromato-graphy)HPLC、Optical Microscope(OM), Scanning Electric Microscope(SEM), Transmission Electron Microscopy (TEM) and other technique. The results were showed as below:(1)relationship between hormone changes and petal senescenceIn the early stage of development, contents of IAA, GA, Zt that regulated the development of petal were high while the content of ABA was low; Content of Aging hormones changed in the development of petal, content of IAA decreased while GA and ZT increased. Content of ETH increased and petals fell off with the senesce of cell aggravated. It was indicated that ETH would be the accelerator of petal senescence other than inducer.(2)relationship between changes in antioxidant system and petal senescenceAntioxidant system in the early petal development played a significant role in renovating of intracellular free radicals, protecting cell membrane lipid peroxidation. But with the reduced capacity of synthesizing enzymes and Vc and other substances of cells, the capacity of the antioxidant system declined, which induce programmed cell death. So, the declined of capacity of antioxidant system promoted the aging, but it was not the induction factor of the cell senescence.(3)relationship between changes of inclusions of cells and petal senescenceCellular inclusion accumulated during the development of cell aging, which reflected the process of cell senescence, the contents of MDA and proline were the important indexes of cell aging. The consumption of phenol and other substances reduced the ability of protection cellular damage. Increase of superoxide anion and the content of hydrogen peroxide caused serious damage to the cell membrane stability and imbalance of metabolism and increased petal senescence.(4)relationship between changes of aromatic substance and petal senescenceAromatic substances in petals during the development process were complex, 37 species of chemical components were identified and most of them increased firstly and then decreased. In this paper, the types and relative content of the aromatic substance at the fourth period were the highest reflected the stage from buds to flower buds were fully grown is mainly synthesized and accumulated precursor of aromatic substances. And then aroma began to distribute with cell senescence of petals.(5) relationship between changes of constructure of cells and petal senescence Starch complexes on parenchyma cells were discovered by HistochemicalStaining. In the progress of the petal development, the size was bigger and bigger and the amount was more and more. The number of starch complexes, mitochondria, lysosomes increased during stageⅡt oⅡby using TEM. Aroma substance transformed from starch complexes whose number gradually indrease was distributed. The epidermal cells of petals collapsed, intercellular space cracked, mitochondria, lysosomes and other organelles disintegrated in various degrees. Petals stripped off with the deformation of cell wall. The trend of cell structure changes of petals during development was basically the same as Programmed cell death.We can conclude from the research above that the change of the perianth cells structure and the physiological and biochemical change have a close relationship with the aging process of the cells.更多还原