Science. 1966 Jul 15;153(3733):305-7. doi: 10.1126/science.153.3733.305.
Polyploidy occurs in the heterosporous and homosporous Pteridophyta, but with a much higher frequency in the latter. Ninety-six percent of the homosporous Pteridophyta show a gametic chromosome number greater than 27, whereas 90 percent of the heterosporous ones possess a gametic chromosome number less than 28. Ultrafrequent establishment of poly- ploidy in the homosporous Pteridophy- ta appears to be necessary to create and maintain genetic variation in the face of the homozygotizing effects of habitual self-fertilization in the monoe- cious gametophytes of these plants.
多倍体存在于异型孢子和同型孢子的蕨类植物中，但后者的多倍体频率要高得多。在同型孢子的蕨类植物中，有 96%表现出配子染色体数目大于 27，而在异型孢子的蕨类植物中，有 90%的配子染色体数目小于 28。在这些植物的单性配子体中，常自花受精导致纯合化，因此同型孢子的蕨类植物中多倍体的频繁建立似乎是创造和维持遗传变异所必需的。
