杂交燕麦(Avena nuda × Avena sativa)的胚胎学研究

The Studies on the Embryology of Hybrid Oat ( Avena nuda×Avena sativa)

研究了裸燕麦和皮燕麦杂交种的胚胎学，结果概括如下：１）花药具四个花粉囊，药壁由四层细胞组成．药室内壁发育为纤维状加厚．中层短命，具腺质绒毡层．伴随着小孢子母细胞的连续型分裂，形成两侧对称型的小孢子四分体．成熟花粉３－细胞型．花粉释放时常出现不孕花粉，一般而论这种现象与无融合生殖有关；２）胚珠倒生，双珠被，厚珠心，珠孔由内珠被组成．孢原细胞直接起大孢子母细胞功能．大孢子母细胞孢质分裂形成直线型的大孢子四分体．合点端大孢子发育为蓼型胚囊，助细胞为镰刀形，它们在极核融合前已退化一个．三个反足细胞分化很早，一般在胚囊发育早期即分化为一群细胞．随后，它们侵入合点端的珠心组织，并且吸收珠心的营养物质，再供胚囊发育之用；３）观察到有无融合生殖现象发生；４）核型胚乳，待大量游离核形成后才形成细胞壁．胚乳边缘的细胞层具次生形成层习性，最后形成种子的糊粉层；５）胚胎发生属紫苑型．

This reseach studies the hybrid species of embryology of the Avena nuda and Avena sativa. The results are summarized as follows:1)The anther is tetrasporangiate and its wall is comprises the four layers of cell.The endothecium develops fibrous thickenings,the middle layers is ephemeral and the cells of the glandular tapetum.Successive cytokinesis in the microspore mother cells accompanies meiosis and the microspore tetrads are isobilateral type.The mature pollen grains are 3 celled.When shed but pollen abortion is commonly associated with apomixis;2) The ovule is anatropous,bitegmic,and crassinucellar,the micropyle formed by the inner integument.The archesporial cell founctions directly as the megaspore mother cell.Cytokiness in the megaspore of a linear tetrad develops into a Polygonum type embryo sac.The synergids may be hooked.While the polar nucleus fuse before they are degenerated one.The 3 antipodal cells differenciated very early.Generally differenciated a groupe cells in early embryo sac development.Them they are intruded to the nucellar tissue of chalaza end,and absorted the vegetative foods of nucellar cells and conduction to the developmend of embryo sac;3) Apomixis is of common occurrence;4) Endosperm formation conforms to the nuclear type and the tissue becomes cellular only after a large number of the nuclei have formed.The peripheral cell layer behaves as a secondary cambium and forms the aleurone layer of the seed;5) Embryogeny conforms to the Asterad type.Polyembryony is common.