Polyploidy and Speciation inPteris(Pteridaceae)

[摘要] The highest frequency of polyploidy among plants is considered to occur in the Pteridophytes. In this study, we focused on polyploidy displayed by a specific fern taxon, the genusPterisL. (Pteridaceae), comprising over 250 species. Cytological data from 106Pterisspecies were reviewed. The base number of chromosomes inPterisis 29. Polyploids are frequently found inPteris, including triploids, tetraploids, pentaploids, hexaploids, and octoploids. In addition, an aneuploid species,P. deltodonBak., has been recorded. Furthermore, the relationship between polyploidy and reproductive biology is reviewed. Among these 106Pterisspecies, 60% exhibit polyploidy: 22% show intraspecific polyploidy and 38% result from polyploid speciation. Apogamous species are common inPteris.Diploids are the most frequent amongPterisspecies, and they can be sexual or apogamous. Triploids are apogamous; tetraploids are sexual or apogamous. MostPterisspecies have one to two ploidy levels. The diverse ploidy levels suggest that these species have a complex evolutionary history and their taxonomic problems require further clarification.

[学科分类] 植物学