The maintenance of separated diploid and polyploid populations within a contact zone is possible due to both prezygotic and postzygotic isolation mechanisms. Niche differentiation between two cytotypes may be an important prezygotic isolating mechanism and can be studied using reciprocal transplant experiments. We investigated niche differentiation between diploid and hexaploid Aster amellus in their contact zone in the Czech Republic. Diploid populations are confined to habitats with low productivity, whereas hexaploid populations occur in habitats with both low and high productivity. Thus, we chose three diploid populations and six hexaploid populations, three in each of the two different habitat types. We analyzed habitat characteristics and carried out reciprocal transplant experiments in the field using both seeds and adult plants. Sites of diploid and hexaploid populations differed significantly in vegetation and soil properties. The mean number of juveniles was higher at sites of home ploidy level than at sites of foreign ploidy level, suggesting niche differentiation between the two cytotypes. On the other hand, transplanted adult plants survived at all sites and juvenile plants were able to establish at some sites of the foreign cytotype. Furthermore, the mean number of juveniles, survival, and flowering percentages were higher at home sites than at foreign sites, indicating local adaptation. We conclude that niche differentiation between the two cytotypes and local adaptation within each cytotype may contribute to the maintenance of diploid and hexaploid populations of A. amellus in their contact zone. Moreover, further factors, such as differences in flowering phenology and exclusion of minority cytotypes, should also be considered.

Department of Botany Faculty of Science Charles University 128 01 Prague Czech Republic

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Trends Ecol Evol. 1992 Sep;7(9):302-7 PubMed

Science. 1987 May 15;236(4803):787-92 PubMed

Evolution. 2007 Jan;61(1):125-40 PubMed

Heredity (Edinb). 1999 Apr;82 Pt 4:381-90 PubMed

Evolution. 2005 Sep;59(9):1936-44 PubMed

Trends Ecol Evol. 1999 Aug;14(8):306-311 PubMed

Am J Bot. 2004 Nov;91(11):1783-8 PubMed

Evolution. 1968 Mar;22(1):108-118 PubMed

Oecologia. 1987 Sep;73(3):436-446 PubMed

Am J Bot. 2005 Nov;92(11):1827-35 PubMed

Ann Bot. 2006 Oct;98(4):845-56 PubMed

Oecologia. 2007 May;152(2):275-85 PubMed

Oecologia. 2008 Aug;157(2):211-20 PubMed

Oecologia. 2005 Aug;145(1):1-8 PubMed

Annu Rev Genet. 2000;34:401-437 PubMed

Ann Bot. 2007 Dec;100(6):1259-70 PubMed

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