Mikroevoluční procesy a meziploidní interakce v sympatrických populacích více cytotypů

Trávníček, Pavel

[Abstract] This thesis is aimed at better understanding of cytotype co-existence in mixed- ploidy populations with an emphasis on a microevolutionary processes behind it. Our past knowledge was based on a few thoroughly investigated model taxa like Chamerion angustifolium and Heuchera grossulariifolia, but some generalizations seem to be premature in the light of new findings. A detailed research of other taxa included in the thesis showed that polyploid complexes can vary dramatically in their ability to cope with the co-existence of cytotypes in mixed-ploidy popu- lations. Whereas mixed-ploidy populations are virtually lacking in some species (an example being Vicia cracca, Paper III.), ploidy-heterogeneous populations are very common in others, maintained by free mating interactions and the absence of reproductive isolation among cytotypes (e.g. Pilosella echioides, Paper II.). The strenght and cumulative effect of various breeding barriers (both pre- or post- zygotic) govern the position of a particular multi-ploidy complex between these two extremes and co-determine the type of cytotype co-existence in its mixed- ploidy populations. Despite the fact that the number of studies revealing cytotype co-existence has been increasing rapidly, evolutionary background and consequences of such co-...

guest :: login Digital Repository
		Search		Submit		Help		About