日本赭纤虫接合生殖的研究——一种体核和生殖核隔代发生的生殖现象的发现

用改进的蛋白银染核法研究了日本赭纤虫哈尔滨品系的接合生殖,发现小核减数分裂的次数和第一次减数分裂的特点与争论中的Miyake等(1979)的结果相同,证明Suzuki(1957)的小核有一次不均等分裂和四对染色体等结论确属误解。还发现本种纤毛虫具有体核(大核)与生殖核(小核)隔代发生的生殖现象。即接合中新大核不来自当代的合子核,而来自上代部分小核的保留和直接发育,当代的合子核只发育成当代的新小核,它们在下一次接合时可能再一部分供发育成下代大核之用,另一部分供减数分裂和受精之用。这种按合现象是在其他纤毛虫中未见报导的。讨论后认为,这种特殊接合现象不是本品系自接所特有,就是本种所固有,但以往被研究者们忽略了。

STUDIES ON THE CONJUGATION IN BLEPHARISMA JAPONICUM THE FIND OF A NEW SEXUAL GENERATIVE MODE OF SOMATIC AND GERMINAL NUCLEAR DERIVATION FROM DIFFERENT ADJOINING GENERATIONS

Conjugation in a Harbin strain of Blepharisma japonicum Suzuki was studied by using an improved protargol technique specific for staining nucleus. The results showed that the number of progamic divisions and the characteristics of progamic division are all identical with those in the results of Miyake et al. (1979) which up to now has been in controversy. It has been also proved that the. result of micronuclei having an unequal sized division and four pairs of chromosomes, as Suzuki reported in 1957, is an apparent misunderstanding. In the conjugation of this ciliate, there is a special nuclear behavior in which the somatic and germinal nucleus derived respectively from two adjoinning sexual generations. During conjugation, the new macronucleus does not come from the contemporary synkaryon, but comes directly from the retained micronuclei of last generation.The contemporary synkaryon only develops into contemporary new micronuclei, some of which, in next conjugation, will develop into macronucleus, and the others of which will be provided for meiosis and fertilization. This mode of conjugation was not reported in other ciliates.Through discussion, the authors hold that this special conjugation mode is either charactetistic of this strain in selling or is inherent for this species but neglected by previous investigators.