Abstract:

Ontogeny and metamorphic development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-May and seeds matured at the beginning of July. The ontogenetic pattern of female reproductive organs of E.sinica is basically similar to that of E.　distachya L. The foliar nature of the outer envelope of the ovule in Ephedra is corroborated. Reduction of ovule number as a tendency of speciation in the genus is substantiated by the occurrence of tri-ovulate cones coupled with comprehensive characters of the genus. The metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are compound while the female reproductive units of the ovulate cone have been reduced from secondary reproductive shoots similar to those of cordaites by phylogenetic transformation, fusion and reduction. Each fertile bract together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of Ephedra .

草麻黄雌性生殖器官的个体发生和畸形式样研究
杨永*

（中国科学院植物研究所，北京100093）

摘要：用扫描电镜观察并分析了草麻黄(Ephedra sinica Stapf)雌性生殖器官的个体发生及畸形式样.该种雌球花个体发生式样与麻黄属其他具双胚珠球果的类群基本一致.外珠被以一对近轴侧突起物出现以及该突起物与苞片成交互排列的发育式样支持前人关于该构造叶性本质的论述,而内珠被与珠心的发育相关,因此可能是真正的珠被.基于返祖性畸形三胚珠球花的出现及其他形态特征,认为麻黄属胚珠数目减少是该属内物种特化的一个趋势;利用雌球花发育的畸形现象及外珠被的形态学本质提出麻黄属的雌球果为复轴性构造,雌性生殖单位是由类似于科达类的次级生殖枝构造经系统发育变态、融合、简化成现存的生胚珠构造式样,每一可育苞片及其腋内雌性生殖单位共同组成了麻黄属的苞鳞-种鳞复合体.

关键词： 麻黄属；雌性生殖单位；个体发生；畸形发育；苞鳞*种鳞复合体

Key words: Ephedra , female reproductive unit, ontogeny, metamorphic development, bract scale and seed scale complex