Distribution, phenology and demography of sympatric sexual and asexual dandelions (Taraxacum officinale s.l.): geographic parthenogenesis on a small scale
| Autor: | Marije H. Verduijn, Peter J. van Dijk, Jos M. M. Van Damme |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Biological Journal of the Linnean Society. 82:205-218 |
| ISSN: | 1095-8312 0024-4066 |
| DOI: | 10.1111/j.1095-8312.2004.00325.x |
| Popis: | In many plant and animal species, sexual and asexual forms have different geographical distributions ('geographic parthenogenesis'). The common dandelion Taraxacum officinale s.l. provides a particularly clear example of differing distributions: diploid sexuals are restricted to southern and central Europe, while triploid asexuals occur across Europe. To get a better understanding of the factors underlying this pattern, we studied the distribution and demography of sexuals and asexuals in a mixed population that was located at the northern distribution limit of the sexuals. In this population three adjacent, contrasting microhabitats were found: a foreland and south and north slopes of a river dike. Comparative analyses of the distribution, phenology and demography indicated that sexuals had a stronger preference for the south slope than did asexuals. We therefore propose that the large-scale geographic parthenogenesis in T. officinale is shaped by an environmental gradient which acts upon the sexuals. [KEYWORDS: agamospermy; apomixis; flowering; microhabitat; polyploidy; triploidy] |
| Databáze: | OpenAIRE |
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