朱顶红精细胞超微结构观察

精细胞是双受精作用的直接参与者，是生殖生物学中的重点研究对象之一。以往的研究表明，应用连续超薄切片和计算机辅助三维重组技术，结合免疫荧光定位，发现两个精细胞在体积和细胞器含量上存在着差异，即精子的二型性，而且与营养细胞核三者构成紧密功能单位即雄性生殖单位（ＭＧＵ），微管对精细胞的性状的确定、运动和维持ＭＧＵ的动态结构稳定具有重要的作用。本文应用透射电镜，详细观察了朱顶红花粉管中精细胞的超微结构，并着重微管结构及其分布的观察。朱顶红成熟花粉为两细胞型。成熟花粉于２６℃、黑暗条件下，在液体培养基（含１０％蔗糖和１００ｐｐｍ硼酸）中培养１３－１８小时，然后收集花粉管，固定，供电镜观察并照相。朱顶红成熟花粉培养１３小时后，生殖细胞在花粉管中完成核分裂和胞质分裂等两个过程。形成两个精细胞。初形成的两个精细胞前后排列，营养核前导并靠近花粉管顶端。领头的精细胞的细胞质以很大的表面与营养核相互贴合（图版Ⅰ－１，２），有时营养核与两个精细胞彼此穿插、缠绕（图版Ⅰ－３）。两精细胞之间的共同壁上具有很多胞质通道和含均质电子密度中等的基质（图版Ⅱ－４）。精细胞质在核与共同壁之间的区域染色较深，经高倍放大，观察到此处含丰富的微管，基

Ultrastructure Features of Sperm Cell in Amaryllis vittata

Ultrastructure of sperm cells in pollen tube of Amaryllis vittata Ait. has been investigated in details by electron microscopy ,with particular emphasis on the organization and distribution of microtubules.The two newly formed sperm cells are arranged in tandem and sometimes in transverse at the right angle to the long axis of the pollen tube.Thevegetative nucleus is ahead and closely associated with the two sperm cells in all examined pollen tubes. The microtubules are distributed in the region between the common cell wall and the proximity of the sperm nucleus,they are singles and dispersed with mainly orientation of longitudinal and oblique,forming a loose bucket-like structure as a whole.In late stage of development,all of the microtubule array longitudinally and enclose the sperm nucleus.This configuration is very similar to the basket-like structure of microtubule in the generative cell. These results show that the organization and distribution of microtubules in the sperm cells are dynamic during cell development.