摘要
研究了裸蒴（ＧｙｍｎｏｔｈｅｃａｃｈｉｎｅｎｓｉｓＤｅｃｎｅ．）的胚胎发育，同时对三白草（Ｓａｕｒｕｒｕｓｃｈｉｎｅｎｓｉｓ（Ｌｏｕｒ．）Ｂａｉｌ．）和蕺菜（ＨｏｕｔｕｙｎｉａｃｏｒｄａｔａＴｈｕｎｂ．）的胚胎也进行了观察。并对三白草科（Ｓａｕｒｕｒａｃｅａｅ）各属间的胚胎学特征进行比较，以探讨三白草科内的系统关系。裸蒴具腺质绒毡层。小孢子同时型，极少数小孢子母细胞的减数分裂Ⅱ不进行，形成有壁的小孢子二分体。四分体以四面体为主，但有少量的二侧对称型、Ｔ型以及十字型四分体。在四分体时期，小孢子发育出现各种异常，大部分小孢子在单核靠边期败育，散粉时花粉空瘪。侧膜胎座。厚珠心。大孢子母细胞在减数分裂Ⅱ时珠孔端的１个细胞不分裂，合点端的１个细胞正常分裂，故形成大孢子三分体，多为直线排列。蓼型胚囊。少数胚囊在四核时期不再分裂，而出现细胞化结构，多数胚囊发育到八核时期。八核胚囊中反足细胞退化较早，卵器存在时间较长。经许多胚胎学特征的比较，认为在三白草科中，三白草属最原始，蕺菜属最进化，裸蒴属和假银莲花属居于二者之间。
The embryological development of Gymnotheca chinensis Decne. isstudied in detail. At the same time, Saururus chinensis ( Lour. ) Baill. andHouttuynia cordata Thunb. are studied, too. Main embryological features of every genus in Saururaceae are compared, and the systematic relationships in Saururaceae are discussed. Tapetum of G. chinensis Decne. is glandular. Microspore is a simultaneous type. A few microspore mother cells don't divide at the end of meiosis Ⅱ and form microspore dyad with walls. Most of the microspore tetrads are tetrahedral and there are a few other types, such as decussate, dilateral and T-shaped tetrad. Microspores have many sterile mutants at the microspore tetrad stage, and most of pollen grains degenerate at the late singe nucleus pollen stage, and pollen grains are empty and shrivelled when dehiscence of anthers at maturity. The pistil of Gymnotheca chinensis is parietal placentation, crassinucellate ovule. At meiosis Ⅱ, the dyad cell near micropyle doesn't divide, however, the other cell beside chalaza splits normally, thus it makes megaspore triad. Most of megaspore triads arrange in a straight line. Its embryo sac is Polygonum type. A few embryo sac stay at the four-nucleus-stage and develop into four-cell-embryo sac, but most of embryo sacs can grow into eight-nucleus-embryo sac. Antipodal cells degenerate early, and egg apparatus exists for a long time. By comparing manyembryological characters, Saururus is considered as the most original genus, Houttuynia the most derived in Saururaceae, Gymnotheca and Anemopsis on the middle evolutionary level.
出处
《云南植物研究》
CSCD
1997年第1期67-74,共8页
Acta Botanica Yunnanica
基金
国家自然科学基金
中国科学院生物分类区系资助
关键词
三白草科
裸蒴
三白草
蕺菜
比较胚胎学
Saururaceae, G. chinensis, S. chinensis, H. cordata, Comparative embryology
