摘要
刺五加Ｅｌｅｕｔｈｅｒｏｃｏｃｕｓｓｅｎｔｉｃｏｓｕｓ（Ｒｕｐｒ．ｅｔＭａｘｉｍ．）Ｍａｘｉｍ．的胚胎发生类型为茄型。其卵细胞受精后，合子经历１５天左右的休眠期才进行第一次分裂。合子分裂通常发生在胚乳细胞化之后，经棒形胚、球形胚、至果实成熟时发育到心形胚。棒形胚后期至心形胚初期，胚柄最为发达。刺五加的胚乳发育类型为核型。其初生胚乳核的休眠期为１天左右。当胚乳游离核数目增加到２００至３００时，胚乳以自由生长细胞壁的方式细胞化，胚乳细胞以典型的有丝分裂方式进一步增殖，增加细胞数目。球形胚时期，胚乳细胞内开始贮藏营养物质。少数种子的胚乳里存在巨大细胞核的异型胚乳细胞。在胚乳游离核为３２至６４个时，分化出珠被绒毡层；球形胚时期，珠被绒毡层解体。珠被绒毡层解体后，胚乳表层细胞分化为分泌层。球形胚至心形胚阶段，约有５％的种子里，胚与胚乳组织发生弥散样降解。成熟果实中，含有大量的瘪粒种子和虫咬种子；饱满种子率为４０％左右。饱满种子中，胚乳组织占据种子体积的绝大部分，胚所占比率很小。
The embryo development of Eleutherococcus senticosus (Rupr. et Maxim.)Maxim. was of the Solanad type. The fertilized egg usually underwent a rest period of 15 days before embarking on its first division. And the first division of the zygote took place after the cellularization of endosperm free nuclei. After the club shaped and the globular embryo period, the heart shaped embryo developed when the fruit became ripe. From the late club shaped to early heart shaped embryo stage, the suspensor grew to its maximum length. The endosperm development of Eleutherococcus senticosus was of the Nuclear type. The rest period of primary endosperm nucleus was about 1 day long. When the number of endosperm free nuclei reached 200～300, the endosperm cellularized through free growing wall formation. The endosperm cells divided by typical mitosis and got filled with reserve food. But in a small number of seeds, there were some huge endosperm cells with a huge nucleus. The endothelium differentiated from the inner epidermis of integument when the number of endosperm free nuclei had increased to 32～64, and disintegrated when the embryo developed into the globular stage. After the disintegration of endothelium, the epidermal cells of endosperm differentiated into a secretory layer. From the globular embryo to heart shaped embryo stage, disintegration of embryo and endosperm occurred in about 5% seeds. In the mature fruits, there were a large amount of shrivelled and insect bitten seeds, and the pulmp seeds made up about 40% of the total. The pulmp seeds were mainly occupied by the endosperm, with a very small embryo. The nutrients of the embryo and endosperm at different stages of development are also discussed.
出处
《植物分类学报》
CSCD
1998年第4期298-304,共7页
Acta Phytotaxonomica Sinica
基金
国家自然科学基金
关键词
刺五加
胚
胚乳
发育
珠被绒毡层
营养供应
Eleutherococcus senticosus
Embryo
Endosperm
Embryo development
Endosperm development
Endothelium
Reserve food
Nutrients
