宁夏枸杞大孢子发生和雌配子体发育的细胞学研究

摘要

采用半薄切片技术和组织化学染色法对宁夏枸杞大孢子发生和雌配子体发育过程中的细胞结构变化及营养物质积累特征进行了观察.结果表明,(1)宁夏枸杞为中轴胎座,多室子房,倒生胚珠,单珠被,薄珠心类型.(2)位于珠心表皮下的孢原细胞可直接发育为大孢子母细胞,减数分裂后形成直线型大孢子四分体,合点端第一个大孢子发育为功能大孢子,胚囊发育类型为蓼型,具有珠被绒毡层.(3)初形成的胚囊外周组织中没有营养物质积累,成熟胚囊时期出现了大量的淀粉粒且呈珠孔端明显多于合点端的极性分布特征.(4)助细胞的珠孔端具有明显的丝状器结构,呈PAS正反应表现出多糖性质,成熟胚囊具有承珠盘结构.%In order to study the cell structure and nutrient accumulation characteristics during megaspore and female gametophyte development in Lycium barbarum,we used semi-thin sectioning and histochemical methods in this study.The main results were as follows:(1) in L.barbarum the ovules attached to the central axis of the ovary which has more locules,and ovules are of anatropous,simple integument and thin nucellus;(2) archesporial cell can directly develop into megaspore mother cell.After meiosis the megasporocyte divided into linear type tetrads.The megaspore in the chalazal end developed into functional one.The development of embryo sac belongs to the polygonum type.The mature embryo sac is surrounded by integument tapetum;(3) in the early period,there were almost no nutrients accumulated in peripheral tissue,but a lot of starch grains appeared in the mature embryo sac,and there are more starch grains in micropylar end than in the chalazal end.The mature embryo sac was composed of an egg apparatus,one central cell with secondary nucleus,3 antipodal cells;(4) the synergid contained obvious filiform apparatus,which had PAS positive reaction,presented the nature of the polysaccharide.At the mature embryo sac stage,some nucellar cells at the chalazal region differentiated into hypostase.