小叶杨(Populus simonii Carr.)种子发育的胚胎学观察

在人工授粉条件下,观察了小叶杨有性生殖过程的形态发育及其持续时间,结果如下:除正常花粉外,有异常和败育花粉,但不影响传粉和受精。胚珠倒生,单珠被,厚珠心,蓼型胚囊,珠孔受精,核型胚乳,胚的发育属柳叶菜型,种缨由胎座表皮细胞发育而成,柱头属湿型,花柱是实心的。人工授粉后4小时,花粉粒90%以上萌发,授粉后48小时,花粉管到达胚囊,双受精作用发生在授粉后3—6天,胚乳游离核时期持续约15—18天,但从胚乳游离核到胚乳细胞全部形成只需2—3天,合子“休眠”6—10天,原胚期约10天,心形期和鱼雷期各约2天,幼胚后期发育迅速,胚体由占种子内全长的1/3至充满整个种子只需5—6天。从授粉到种子成熟,历时约一个月。

ON THE EMBRYOLOGICAL OBSERVATIONS OF THE SEED DEVELOPMENT OF POPULUS SIMONII CARR.

1. There are two types of stamens.The fertile produces normal pollen grains and then splits,while the sterile produces abnormal pollen grains and does not split.The great mass of normal pollen grains make pollination possible. 2. The chalazal megaspore of a linear or T-shaped tetrad develops in a Polygonum type of embryo sac. 3. Pollen tube enters into the ovule through micropyle(porogamy). 4. The embryogeny conforms to the "Onagard type". 5. The "cotton" of the seeds develops from the epidermal cells of the placenta. 6. A schedule of time in relation to reproductive phase is given.