西瓜小孢子有丝分裂前后质体和线粒体的变化  

Changes of Plastid and Mitochondria Before and After Microspore Division in Watermelon

作　　者：刘林[1] 

机构地区：[1]临沂大学生命科学学院,山东临沂276000

出　　处：《园艺学报》2012年第12期2468-2474,共7页Acta Horticulturae Sinica

基　　金：山东省自然科学基金项目(ZR2011CL002);临沂大学科研计划项目(HX09104)

摘　　要：为揭示西瓜小孢子有丝分裂前后质体和线粒体的变化以及它们向生殖细胞和营养细胞分配的特点,用透射电子显微技术对西瓜不同发育阶段小孢子及早期二细胞花粉的质体和线粒体进行比较研究。结果表明,小孢子的质体结构简单,不积累淀粉等贮藏物质,为原质体;二细胞花粉的质体不含内部膜系统,但积累大量淀粉,表明小孢子有丝分裂引起原质体向造粉体分化。二细胞花粉的质体都在营养细胞中,生殖细胞不含质体,显然,小孢子分裂过程中质体只分配给营养细胞而不分配给生殖细胞,这一不均等分配方式决定质体呈单亲母系遗传,据此,将西瓜的质体遗传细胞学机制归类为番茄型。小孢子的线粒体内嵴较少,营养细胞和生殖细胞的线粒体内嵴较多,显示小孢子分裂后线粒体结构复杂化。To understand morphological changes of plastids and mitochondria before and after microspore division as well as the distribution of these organelles to vegetative and generative cells during microspore division, microspores at different developmental stages and newly born 2-celled pollen grains were investigated by means of transmission electron microscopy. Plastids in microspores at all developmental stages do not have internal membranous structures, and do not accumulate starch or any other forms of storage reserves, indicating an undifferentiated status. In contrast, plastids in the newly born 2-celled pollen grain accumulate a huge amount of starch, indicating that the microspore division stimulates differentiation of proplastids into amyloplasts. In the newly born 2-celled pollen grain, the generative cell does not contain plastids, while the newly born vegetative cell contains a large number of plastids, indicating a complete exclusion of plastids from the generative cel! during microspore mitotic division, i.e., watermelon possesses the mode of purely maternal plastid inheritance. Based on cytological observations, watermelon should be added to the list of Lycopersicon type. Mitochondria in microspores reveal few cristae, whereas cristae dramatically increase in number in 2-celled pollen grains.

关 键 词：西瓜 小孢子 二细胞花粉 质体 线粒体 

分 类 号：S651[农业科学—果树学]