C-Banding Patterns and Quantitative Karyotype Characteristics of Bulgarian Species of Crepis (Asteraceae)

摘要

Giemsa C-banded idiograms were established from eight Crepis species of Bulgarian origin (Crepis viscidula, C. paludosa, C. conyzaefolia, C. bithynica var. bithynica and var. fodorii, C. pulchra, C. sancta, C. setosa, and C. zacintha) that had been previously studied for genome size and karyotype shape using classical methods. All taxa are diploids with descending chromosome numbers, x = 6, 5, 4, and 3. Satellites were always heterochromatic. Small but distinct centromeric bands were of general occurence (except perhaps in C. paludosa) and terminal bands were present at least in some chromosomes of the karyotypes. Higher amounts of heterochromatin in the form of terminal and intercalary bands were found in C. bithynica and C. zacintha, but banding patterns were not so specifically similar as to indicate common origin. There are a number of particular karyotypic characters which may turn out to be phylogenetically significant when corresponding information on many related taxa becomes available. Correlations of karyotypic parameters were calculated. In heterochromatin only percent heterochromatin, but not absolute heterochromatin amount, and genome size were significantly correlated. This is the result of a strong euchromatin variation but independent heterochromatin variation.