Cytological and molecular genetic studies on introgressive hybridizations among genus Arachniodes Blume (Dryopteridaceae; Pteridophyta)

我们为日本复叶耳蕨（鳞毛蕨科;蕨类植物门）的几种二倍体（2n = 82）物种之间的后代杂交提供了细胞学、形态学和分子遗传学证据。5个天然杂种，A.山核桃Kurata，A. x intermedia Shimura（A. aristata（Forst.）Tindale x sporadosora（Kunze）Nakaike）、黑腹拟青霉A. x simulans（Ching）Ching，拟扁蚜A. x tomitae Sa. Kurata和A. x masakii Sa. Kurata在减数分裂中期Ⅰ（32 Ⅱ ~ 41 Ⅱ）表现出较高的二价体形成，每个孢子囊产生64个孢子。孢子萌发率为20-50%，发育成原叶体，发育出精子器和颈卵器。在A. aristata和A. sporadosora的叶绿体单倍型和两个等位酶基因型的植株。这些个体只能通过杂种F_1间的交配或后代杂交产生。在这个网站的形态变化的模式是一致的分子数据，我们的细胞学，形态学和分子遗传学数据表明，人口是一个混合的群体。我们的数据证实了唯一已知的情况下，涉及温带亚洲蕨类植物杂交已经超越了F_1代在二倍体水平。

We present cytological, morphological, and molecular genetic evidence for later-generation hybridization among several diploid (2n = 82) species of Arachniodes Blume (Dryopteridaceae; Pteridophyta) in Japan. Five putative natural hybrids, A. x tohtomiensis Sa. Kurata, A. x intermedia Shimura (A. aristata (Forst.) Tindale x sporadosora (Kunze) Nakaike), A. x simulans (Ching) Ching, A. x tomitae Sa. Kurata, and A. x masakii Sa. Kurata, displayed high bivalents formations at meiotic metaphase I, from 32II to 41II, and produced normal shaped 64 spores per sporangium. Their spores germinated at 20-50% and grew to prothallia that developed antheridia and archegonia. In a mixed-species population in which A. aristata and A. sporadosora grew together, several plants were found it have the chloroplastic haplotype of one of the species and the two-loci allozymatic genotype of the other. Such individuals can only have arisen via matings between F_1 hybrids or by later-generation hybridization. The pattern of morphological variation at this site is consistent with the molecular data, and our cytological, morphological, and molecular genetic data suggest that the population is a hybrid swarms. Our data confirm the only known case involving temperate-zone Asian pteridophytes where hybridization has gone beyond the F_1 generation at the diploid level.