Ultrastructural analysis of cell component distribution in the apical cell ofCeratodon protonemata
Ultrastructural analysis of cell component distribution in the apical cell ofCeratodon protonemata
复制标题
原丝角齿兽顶端细胞细胞成分分布的超微结构分析
作者：
L. Walker;F. Sack
顶端生长的植物细胞的一个显著特征是细胞成分沿细胞长度分布不同，尽管大多数超微结构分析都是定性的。本文从定性和定量两个方面研究了黑生原体顶端细胞中细胞成分的纵向分布。利用透射电镜对顶端细胞前35 μm进行了立体分析。沿细胞轴线分布有四种类型，其中三种类型是不同的：(1)管状内质网均匀分布；(2)池状内质网和高尔基囊泡沿尖端到基部梯度分布；(3)质体、液泡和高尔基堆积在特定区域富集，但富集位置不同；(4)线粒体在最顶端的5 μm内不存在，其余30 μm均匀分布。本研究提供了一个最全面的定量，超微结构分析细胞成分的分布在任何尖端生长的植物细胞的顶端。几乎每个成分都有自己的空间排列，这一发现表明了尖端生长细胞中成分分布的组织和调节的复杂性。
A distinctive feature of tip-growing plant cells is that cell components are distributed differentially along the length of the cell, although most ultrastructural analyses have been qualitative. The longitudinal distribution of cell components was studied both qualitatively and quantitatively in the apical cell of dark-grown protonemata of the mossCeratodon. The first 35 μm of the apical cell was analyzed stereologically using transmission electron microscopy. There were four types of distributions along the cell's axis, three of them differential: (1) tubular endoplasmic reticulum was evenly distributed, (2) cisternal endoplasmic reticulum and Golgi vesicles were distributed in a tip-to-base gradient, (3) plastids, vacuoles, and Golgi stacks were enriched in specific areas, although the locations of the enrichments varied, and (4) mitochondria were excluded in the tipmost 5 μm and evenly distributed throughout the remaining 30 μm. This study provides one of the most comprehensive quantitative, ultrastructural analyses of the distribution of cell components in the apex of any tip-growing plant cell. The finding that almost every component had its own spatial arrangement demonstrates the complexity of the organization and regulation of the distribution of components in tip-growing cells.