TY  - GEN
A1  - Bareither, Nils
A1  - Scheffel, André
A1  - Metz, Johannes
T1  - Distribution of polyploid plants in the common annual Brachypodium distachyon (s.l.) in Israel is not linearly correlated with aridity
N2  - The ecological benefits of polyploidy are intensely debated. Some authors argue that plants with duplicated chromosome sets (polyploids) are more stress-resistant and superior colonizers and may thus outnumber their low ploidy conspecifics in more extreme habitats. Brachypodium distachyon (sensu lato), for example, a common annual grass in Israel and the entire Mediterranean basin, comprises three cytotypes of differing chromosome numbers that were recently proposed as distinct species. It was suggested that increased aridity increases the occurrence of its polyploid cytotype. Here, we tested at two spatial scales whether polyploid plants of B. distachyon s.l. are more frequently found in drier habitats in Israel. We collected a total of 430 specimens (i) along a largescale climatic gradient with 15 thoroughly selected sites (spanning 114–954 mm annual rainfall), and (ii) from corresponding Northern (more mesic) and Southern (more arid) hill slopes to assess the micro-climatic difference between contrasting exposures. Cytotypes were then determined via flow cytometry. Polyploid plants comprised 90% of all specimens and their proportion ranged between 0% and 100% per site. However, this proportion was not correlated with aridity along the large-scale gradient, nor were polyploids more frequently found on Southern exposures. Our results show for both spatial scales that increasing aridity is not the principal driver for the distribution of polyploids in B. distachyon s.l. in Israel. Notably, though, diploid plants were restricted essentially to four intermediate sites, while polyploids dominated the most arid and the most mesic sites. This, to some degree, clustered pattern suggests that the distribution of cytotypes is not entirely random and calls for future studies to assess further potential drivers.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 334 
KW  - Aridity
KW  - Brachypodium distachyon
KW  - Brachypodium hybridum
KW  - Brachypodium stacei
KW  - cytotype
KW  - exposition
KW  - Israel
KW  - Mediterranean grass species
KW  - polyploidization
KW  - rainfall gradient
KW  - slope aspect
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-395293
ER  -