New Chromosome Numbers and Karyotype Analysis of Tordylium (Apiaceae) Species with Emphasis on Their Systematics and Evolutionary Significance

Abstract

In Turkey, there are eighteen Tordylium (Apiaceae) species out of twenty in the worldwide and seven of them are endemic. In this research, karyotypes of T. apulum, T. pestalozzae, T. syriacum, T. trachycarpum and karyotypes and chromosome numbers of T. cappadocicum, T. aegaeum, T. hasselquistiae, T. ketenoglui (endemic), T. macropetalum (endemic), T. pustulosum (endemic) are provided for the first time. Tordylium species were separated into five cytotypes according to chromosome numbers as 2n=8, 16, 18, 20 and 22. Besides, idiograms of haploid chromosome set, length of the chromosome arms, arm ratios, centromeric index, relative length and haploid karyotype formulas are given. T. ketenoglui has longest chromosome lengths (3,39–1,66 µm) while T. aegaeum has shortest (1,10–0,59 µm). Additionally, principal component analysis (PCA) was performed by quantitified karyological characters. PCA results showed that the median type and haploid chromosome length have significant variants among karyological characters. Also, it is discussed correlation among karyological data, current infrageneric classification and the phylogenetic hypothesis based morphological dataset of Tordylium. Karyological characters are incompatible with current infrageneric classification, similarly with conflict between the phylogenetic hypothesis and infrageneric classification. In the light of the phylogeny, it can be said that the ancestral number is 2n=16.