棘尾虫无小核镜像骈体的获得及其生殖行为的实验观察

用在分裂期进行显微手术的方法和在陈旧培养中诱导的方法,从贻贝棘尾虫天然无小核系S_(10)中获得了无小核镜像骈体。对骈体的各种生殖行为进行了观察,并用孚尔根和改进的黑色素染色技术揭示了它们的细胞学细节。发现在本文描述的无小核骈体和过去报告的有小核骈体之间,在二分裂和生理再生上没有显著区别。无小核骈体和正常单体S_7之间的接合命运则是多样化的。在630个这样的接合对中,有257对发生了真正的接合并形成接合后体;有153对接合不久包囊化;在其余的220对中,一个接合体吸收了另一个,变成营养型的单体和有小核的骈体。前者占总吸收者的96.8％,后者只占3.2％。对接合和吸收两种情况的细胞学事件进行了详细观察。无小核骈体中的两组细胞质和双套大核能吸引其配偶中的小核,形成自己新的双套大核胚基及小核胚基,在本文的讨论中受到充分注意。

INDUCTION OF AMICRONUCLEATE MIRROR-IMAGED DOUBLET IN THE CILIATE STYLONYCHIA MYTILUS AND OBSERVATIONON ITS REPRODUCTIVE BEHAVIOR

Amicronucleate mirror-imagel doublets were obtained from a natural amicronucleate stock of Stylonychia mytilus by means of microsurgical operation in division stage and of inducing in stale cultures. Various reproductive behaviors of the doublet were observed and their cy-tological details were demonstrated by Fculgen stain and modified Nigrosin stain techniques. It was found that there were no distinct differences in binary fission and physiological regeneration between amicronucleate doublet observed in the present work and micronucleate doublet reported previously. The fate of conjugation between amicronucleate doublet and normal single of stock S7 was diversified. Among 630 pairs of this kind of conjugation 257 pairs underwent true conjugation and resulted in doublet and sigle exconjugants, 153 pairs encysted soon after mating, and in the rest 220 pairs, one partner absorbed the other, becoming vegetative normal singles and micronucleate doublets. The former make up 96.8% of the total absorbents, while the latter only 3.2% of them. Cytological events both in conjugation and absorbtion were observed in detail. The fact that the double cytoplasm and double macronuclei in the amicronucleate doublet can attract the micronuclear product of its partner to form its own new double macro- and micronuclear anlagen was discussed.