丫蕊花的双受精及胚和胚乳发育的初步观察

丫蕊花（Ypsilandra thibetica Franch.)为珠孔受精，进入胚囊的两个精子分别与卵细胞和中央细胞进行正常的双受精，其受精作用属有丝分裂前型，受精后的初生胚乳核立即分裂，其发育方式为沼生目型，到发育后期，由游离状态的胚乳核形成胚乳细胞时，珠孔室和合点室都形成胚乳细胞，合子的休眠期很长，而且胚的发育过程较为缓慢，种子成熟时胚尚无器盲的分化，本文还观察了以上发育过程中淀粉粒，蛋白质的动态。

A PRELIMINARY OBSERVATION ON THE DOUBLE FERTILIZATION AND POST-FERTILIZATION DEVELOPMENT OF YPSILANDRA THIBETICA FRANCH.

Some investigations on the processes of double fertilization,endosperm development and embryogenesis,together with certain histo-chemical reactions in Ypsilandra thibetica Franch. have been made Their main features are:1.The entry of pollen tube is porogamy and do- able fertilization proceeds normally.It be longs to premitotic type.2.The first division of the primary endosperm nucleus is followed by cell wall formation giving rise to a larger micropylar and a smaller chalazal chamber.But there is no further wall formation in the later nuclear divisions until the endosperm is nearly mature.Hence,it belongs to the He- lobial type of development.Nuclear divisions tend to proceed faster in the micropylar than in the chalazal chamber and lately all freenuclei in both chambers become cellular when the proembryo consists of about four or eight cells.During the proembryogenesis some endo- sperm cells surrounding the proembryo degenerate gradually.3.The zygote has a longer period of dormancy and slower rate of development than usual.When the seeds are mature, the embryos in them are not differentiated into organs yet.There are two types of embryo- genesis.Some are of the Caryophyllad type,while in others,the basal cell of the two-celled proembryo divides vertically so that two basal cells stand longitudinally parallel to each other forming the base of the suspensor.4.The development of starch and accumulated protein grains in the process of double fertilization,embryogenesis and endosperm development were also,observed.