沙枣（Elaeagnus angustifolia L.）的胚和胚乳发育

本文报道了沙枣受精前后,胚囊的结构和胚珠、胚囊中组织化学变化,以及胚和胚乳的发育,胚乳母细胞早于受精卵发育。为核型胚乳,胚乳发育早期,胚囊中富含蛋白质,胚胎发育为紫苑型,当多细胞原胚吋,胚乳开始形成细胞壁,胚细胞中含少量淀粉粒和可溶性蛋白质,这时候,胚柄极为发达,心形胚时,胚乳巳全部形成细胞壁,但局限于胚囊边缘,鱼雷形胚时,胚柄开始退化。以后,随着子叶的发育和生长,胚乳渐被吸入,接近成胚期,胚已为发达的子叶所取代,沙枣为无胚乳种子,成胚的子叶发达,于基部外方具一舌状物。

Development of Embryo and Endosperm in Elaeagnus angustifolia L.

This study reports the structure of embryo sac and histochemical changes in the ovule and embryo sac, belete and after fertilization, and the development ot embryo and endosperm. The endosperm mother cell develops earlier than the zygote. The endosperm of Elaeagnus angustifolia L. is nuclear type. In the early stage of endosperm development, the embryo sac is rich in proteins. The emryoyeny conforms to Asterad type. During the multicellular proembryo, the endosperm begin to form cell wall; and small amount of starch grains and solubele protein are present in the embryonic cells. At that time, the suspensor is well developed. At the heart stage of embryo, the cell wall of endosperm is fully formed, but it is restricted in the edge of embryo sac. At torpeds stage, the suspensor begins degeneration. Then, with the development and growth of cotyledons, the endosperm is gradually absorbed. Approaching to the mature embryo stage, the endosperm has been replaced by the developed cotyledons. The seeds of Elaeagnus angustifolia L. are exalbuminous. The mature embryonic cotyledons are developed. A ligular-like structure is located at the external position of cotyledanary basic portion.