中国淡水三角涡虫染色体变化与生殖的关系

利用空气干燥法对淡水三角涡虫的染色体进行研究。结果表明：三角涡虫的染色体数目为n=8，2n=16，2n=24，为二倍体2n=2x=16、三倍体2n=3x=24和混合倍体2n=2x=16，2n=3x=24，有时也可见到非整倍体。以有性生殖为主的类群．有性生殖期间有性个体大量存在，生殖器官比较发达．染色体为二倍体；以无性生殖为主的类群，很少出现有性个体，染色体为三倍体；既有有性生殖又有无性生殖的类群，有性生殖期间，生殖器官发育稍差，染色体主要为混合倍体．有时出现二倍体或三倍体。本文对影响三角涡虫性成熟的因素也进行了讨论。

The Relationship between the Reproduction and the Chromosomal Variation of Freshwater Planarians(Dugesia) in China

The chromosomes of Dugesia sp. from various stations were studied by air-drying technique. The results have shown that the chromosome numbers of Dugesia sp. were n=8, 2n=16, and 2n=24. Their karyotype included diploid 2n=2x=16, triploid 2n=3x=24 and mixoploid 2n=2x=16, and 2n=3x=24.Aneuploidic karyotype may occur. Sometimes, there were accessory chromosomes in some specimens. The reproduction included sexual and asexual reproduction, sexual reproduction in winter, and asexual reproduction in summer. The chromosomes in groups whose reproductive organs are well-developed are diploid during the reproduction. The chromosomes in some groups, whose reproduction are mainly asexual, are triploid. The chromosomes in groups whose reproductive organs are less-developed mainly are mixoploid, and sometimes are diploid or triploid. The factors of influence on the living sexually mature of Dugesia sp. were discussed in the article.