Distribution and Ecology of Aster amellus aggregates in the Czech Republic

0045310 - BÚ 2007 RIV GB eng J - Článek v odborném periodiku
Mandáková, T. - Münzbergová, Zuzana
Distribution and Ecology of Aster amellus aggregates in the Czech Republic.
[Distribuce a ekologie cytotypů druhu Aster amellus v České republice.]
Annals of Botany. Roč. 98, - (2006), s. 845-856. ISSN 0305-7364. E-ISSN 1095-8290
Výzkumný záměr: CEZ:AV0Z60050516
Klíčová slova: Distribution * Ecology * Aster amellus
Kód oboru RIV: EF - Botanika
Impakt faktor: 2.448, rok: 2006

Background and Aims Polyploidy is viewed as an important mechanism of sympatric speciation, but only a few studies have documented patterns of distribution and ecology of different cytotypes in their contact zone. Aster amellus agg. (Asteraceae) is one of the species with documented multiple ploidy levels. The aim of this study was to determine spatial distribution and ecology of two cytotypes, diploid (2n = 18) and hexaploid (2n = 54), of Aster amellus agg. at their contact zone in the Czech Republic. center dot Methods Root-tip squashes and flow cytometry were used to determine the ploidy of 2175 individuals from 87 populations. To test whether some differences in ecology between the two ploidy levels exist, in each locality releves were recorded and abiotic conditions of the sites were studied by estimating potential direct solar radiation, Ellenberg indicator values and above-ground biomass. center dot Key Results Together with diploid and hexaploids, minorite cytotypes (triploid, pentaploid and nonaploid) were found. No significant ecological differences between diploid and hexaploid cytotypes were found. In spite of this, no population consisting of both of the two basic cytotypes was found. center dot Conclusions The results of this study show that the contact zone of diploid and hexaploid cytotypes in the Czech Republic is much more diffuse than indicated in previous records. Although populations of both cytotypes occur in close proximity (the closest populations of different cytotypes were 500 m apart), each individual population consists of only one basic ploidy level. This was unexpected since there are no clear differences in abiotic conditions between populations. Taken together with the absence of an intermediate tetraploid cytotype and with reference to published world distributional patterns of different ploidy levels, this suggests a secondary contact zone. Detailed genetic study is, however, necessary to confirm this.

Cílem projektu bylo prostudovat rozšíření a ekologii diploidních a hexaploidních populací druhu Aster amellus v České Republice. Výsledky ukazují, že Česká republika se nachází v kontaktní zóně obou cytotypů. V práci nebyli nalezeny žádné smíšené populace druhu a to přes to, že se populace obou ploidií vyskytují velmi blízko sebe. Zajímavé také je, že nebyl nalezen žádný ekologický faktor diferencující obě ploidie. Pro pochopení pozorovaného pattern jsou potřeba další podrobnější studie.
Trvalý link: http://hdl.handle.net/11104/0137868