蒲桃胚胎发育及多胚来源的初步研究

观察了蒲桃花果的形态结构和胚胎发生.蒲桃胚囊的发育属蓼型.每个蒲桃子房内有10多个胚珠,但成熟果实内多数只有1粒种子,少数为2粒,原因为一些胚囊不能发育成熟,而那些成熟的胚囊又有一部分不能顺利地完成双受精.蒲桃胚乳发育属核型.在受精之前,多数珠心的表皮下即有珠心胚原细胞出现,这些细胞分裂成为不定胚的原始体.随着某些珠心内的胚囊败育,这些不定胚原始体也归于消亡.而那些顺利完成双受精的胚囊外的不定胚原始体则可往胚囊方向靠拢,并进一步侵入胚囊.通常,侵入胚囊的珠心胚达5—9个.此外,也观察到了裂生多胚现象.最终,每粒发育成熟的种子内存有2-10个胚,合子胚、裂生胚和珠心胚混杂在一起.

Preliminary Observations on the Early Embryogeny and the Origin of Polyembryony in Rose-apple

The morphological and anatomic observations of flower and fruit inRose—apple and its embryogeny were carried out. The development of embryo sac belongs to polygonum type. Although there may be more than ten nucellus in each ovary, only one or two nucellus could develop completely. The development of the endosperm belongs to nuclear type. Before fertilization, some epidermal cells of nucelJus at the micropylar end divided into proembryo with 2-3 cells, however, only were they develop along with the development of fertilized egg, and finally invaded into embryo sae. Cleavage polyembryony was also observed. Therefore, as many as 6 embryos in one embryo sae. The application of polyembryony in Rose-apple was discussed.