Cytological and Genetic Study of Two Putative Hybrids and Their Parents of Athyrium (Woodsiaceae; Pteridophyta) in Yakushima Island, Southwestern Japan

Abstract

The mitotie ebromosome number, mejotie behavior and sporogenesis, allozyme variation, chioroplasi DNA type, and morphological characteristica of two putative hybrids and their putative parenta of Athyrium jo Yakushima Island, southweatern Japan, were studied. Athyrium xfiavosorum it a aterile hypotetraploid (2n - 159), and ita putative parenta A. arisanense andA. subrigescens are a aexually reproductive hypotetraploid (2n - 158) and a sexual tetraploid (2n - 160), respeetively. Allozyme and morphologieal analyseo showed that, A. xfiavosorum displayed intermediate charaeteristico between A. arisanense and A. subrigescens. The chioroplasi DNA analysis ohowed that, A. arisanense and A. xfiavosoram had the same SSCP-PCR bandmg pattem. Athyrium xpurpurascens is a atedie tetraploid (2n - 160), and ita putative parenta, A. subrigescens and A. kuratae, are sexually reproductive tetraploida (2n = 160). Allozyme and morphological analysea revealed thaI A. xpurpurascens waa an intermediate between A. subrigescens and A. kuratae; the chloroplast DNA of A. xpurpurascens waa the same as that of A. kuratae. Theae data did not contradici the hypotheais thaI A. xfiavosorum originated from a hybridization between A. arisanense and A. subrigescens, whereas A. xpurpurascens originate from a hybridization between A. kuratae and A. subrigescens