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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 reveal the changes of plastids and mitochondria in watermelon microspores before and after mitosis and their distribution to germ cells and vegetative cells, the plastids and mitochondria of microspores and early two-cell pollens in different developmental stages of watermelon were compared by transmission electron microscopy the study. The results showed that the microspores had a simple plastid structure without accumulation of storage materials such as starch and the like. The plastid of the two-cell pollen did not contain the internal membrane system but accumulated a large amount of starch, indicating that microspore mitosis caused protoplast growth Powder differentiation. Two plastids of plastid plastids are in vegetative cells, germ cells contain no plastid, apparently, the plastid microspore division process is only assigned to vegetative cells and not assigned to germ cells, this unequal distribution of plastid Single parental inheritance, therefore, the watermelon plastid genetic cytology classified as tomato type. Microspores had fewer mitochondrial inner ridges and more mitochondrial ridges in vegetative and reproductive cells, suggesting that the mitochondrial structure was complicated after microspore division.