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Ultrastructural and microbiological research of the double fertilization in angiosperm

被子植物双受精的超微结构和微生物学研究

基本信息

批准号：
12640646
负责人：
KUROIWA Haruko
金额：
$ 2.11万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640646/
关键词：
Pelargonium zonale double fertilization egg cell giant mitochondria mitochondrial DNA amyloplast zygote ミトコンドリアDNA 原色素体

项目摘要

Changes in the distribution of organelles and organelle-DNA in Pelargonium zonale from the mature egg cell stage to the first zygotic division during the early stages of embryogenesis were investigated using electron microscopy and fluorescence microscopy. The mature egg is a large, polarized bulbous-shaped cell tapering toward its micropylar end. The wide chalazal region has a large nucleus that is surrounded by cytoplasm containing many giant mitochondria and large amyloplasts. The mitochondria contain a large amount of mitochondrial DNA (mt-DNA) and appear as long stretched rods or complex rings, sometime consisting of several concentric or half-concentric circles in sections. The tme of pollination to cell fusion is approximately 6 to 9 h and is 20 to 24 h until the first zygotic division. The changes in the zygote and its organelles preparatory to division occur in 3 stages. At stage 1 (6-9 h after pollination), cell fusion occurs and the zygote bigins to elongate. Many vacuoles o … More f varying size appear surrounding the nucleus. At stage 2 89-15 h), the zygote nucleus migrates to a central position in the cell and the mitochondria form a single ring that becomes either irregularly crushed or appears as long thin strings. Amyloplasts exhibit a gradual decrease in the number of starch grains. At stage 3 (15-20 h), the vacuoles disappear, except for a few that remain in the micropyolar region and cell size decreases. Mitochondria become short, fine strings or small rings. Amyloplasts with starch grains are no longer observed, but are transformed into large proplastids. Following the first division of the zygote approximately equal-sized apical and basal cells are formed. Short rod-shaped or small ring-shaped mitochondria are randomly distributed near the nucleus of the apical cell, whereas mitochondria in the basal cell are long and rod-shaped. Inthe electron microscope, two types of plastids can be distinguished : dark oval plastids originating from the sperm cell, which are observed in both apical celland basal cell, and others with a less dense, amorphous matrix, believed to originate from egga amyloplasts, which are unevenly distributed in the micropylar region of the basal cell. fluorometry using video-intensified microscope photon counting system (VIMPICS) reveals that, correlated with changes in mitochondrial morphology, DNA amount within the mitochondrion decreases linearly during these stages. Less

用电子显微镜和荧光显微镜研究了天葵胚胎发育早期从成熟卵细胞到第一次合子分裂期间细胞器和细胞器DNA的分布变化。成熟的卵是一个大的，极化的球状细胞，向其珠孔末端逐渐变细。宽阔的合点区域有一个大的核，核被细胞质包围，胞浆中含有许多巨大的线粒体和大的淀粉样体。线粒体含有大量的线粒体DNA(mt-DNA)，呈现为伸展的长棒或复杂的环，有时由几个同心或半同心的圆组成。授粉到细胞融合的时间约为6~9h，直到第一次合子分裂的时间约为20~24h。受精卵及其细胞器准备分裂的变化分3个阶段进行。阶段1(授粉后6-9h)，细胞融合，合子大黄素伸长。…上有许多空泡更多的不同大小的核出现在细胞核周围。在第二阶段89-15h)，合子核迁移到细胞的中心位置，线粒体形成一个单环，变得不规则地压碎或看起来像细长的线。淀粉体的淀粉粒数量逐渐减少。在阶段3(15-20h)，液泡消失，除了少数残留在微脓泡区的空泡，细胞尺寸变小。线粒体变短、细绳或小环。不再观察到含有淀粉粒的淀粉体，而是转化成大的原生质体。受精卵第一次分裂后，形成大小大致相同的顶端细胞和基细胞。顶端细胞核附近有短棒状或小环状线粒体，而基细胞内线粒体较长且呈杆状。在电子显微镜下，可以区分出两种类型的质体：一种是起源于精子细胞的深色椭圆形质体，在顶端细胞和基底细胞中都能观察到；另一种是密度较低的无定形基质，据信来自于EGGA淀粉体，它们不均匀地分布在基底细胞的珠孔区。用视频增强显微镜光子计数系统(VIMPICS)进行的荧光检测显示，随着线粒体形态的改变，线粒体内的DNA含量在这些阶段呈线性下降。较少