Cryptopolyploidy revisited: the case of Vinca (Apocynaceae)

This investigation presents a look back to ancient times of karyology with modern optical instruments. `Cryptopolyploidy', i.e. an intrinsically polyploid but numerically non-polyploid structure of chromosome complements, today is an obsolete concept of chromosome architecture and evolution, but was actively discussed up to the mid-seventies of the past century. We focus here at a hypothesis of cryptooctoploidy in Vinca difformis (2n = 46), which was based on a measured four-fold chromosome volume compared with V. minor (2n = 46), the proposed diploid. We used DNA flow cytometry and Feulgen densitometry to see, if the postulate of cryptooctoploidy in V. difformis in the retrospect could be justified. It was found not defendable, because V. difformis differed only about 1.55-fold in C-value from V. minor, which is far from a regular multiple and much less than the 4-fold. C-values are given also for V. major, V. herbacea and V. rosea.