Molecular Phylogeny and Chromosomal Evolution of Japanese Schoenoplectus (Cyperaceae), Based on ITS and ETS 1f Sequences

概要

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ITS and ETS If sequence data were used to estimate the phylogeny of 13 Japanese Schoenoplectus species, and karyomorphological observations were made on 14 species of this genus. Two major clades were identified in the Japanese Schoenoplectus molecular phylogenetic tree: (1) one including all species of section Actaeogeton, and (2) the another comprising the two sections Malacogeton and Schoenoplectus. Phylogenetic analysis, including three published species of section Schoenoplectus, supported a monophyly of the two major clades. These molecular phylogenetic data also support the intrageneric relationships and morphological characters of genus Schoenoplectus, as defined by Smith & Hayasaka (2001). The section Actaeogeton clade and the sections Malacogeton and Schoenoplectus clade showed the same chromosomal evolution; each clade had both high and low chromosome numbers. The high chromosome numbers may arise by polyploidy because chromosome sizes were almost equal in both. Therefore, chromosomal evolution in the genus Schoenoplectus may be caused more by polyploidy more than aneuploidy. In our study, the putative natural hybrids, S. × trapezoideus and S. × uzenensis were found. The chromosome number of S. × trapezoideus was 2n=43 and S. × uzenensis was 2n=58. These two hybrids had an intermediate chromosome number of both putative parents.
日本植物分類学会の論文
2005-08-20