title: Apomixis is not prevalent in subnival to nival plants of the European Alps.
abstract: OBJECTIVE
  High alpine environments are characterized by short growing seasons, stochastic climatic conditions and fluctuating pollinator visits. These conditions are rather unfavourable for sexual reproduction of flowering plants. Apomixis, asexual reproduction via seed, provides reproductive assurance without the need of pollinators and potentially accelerates seed development. Therefore, apomixis is expected to provide selective advantages in high-alpine biota. Indeed, apomictic species occur frequently in the subalpine to alpine grassland zone of the European Alps, but the mode of reproduction of the subnival to nival flora was largely unknown.
  
  
  METHODS
  The mode of reproduction in 14 species belonging to seven families was investigated via flow cytometric seed screen. The sampling comprised 12 species typical for nival to subnival plant communities of the European Alps without any previous information on apomixis (Achillea atrata, Androsace alpina, Arabis caerulea, Erigeron uniflorus, Gnaphalium hoppeanum, Leucanthemopsis alpina, Oxyria digyna, Potentilla frigida, Ranunculus alpestris, R. glacialis, R. pygmaeus and Saxifraga bryoides), and two high-alpine species with apomixis reported from other geographical areas (Leontopodium alpinum and Potentilla crantzii).
  
  
  RESULTS
  Flow cytometric data were clearly interpretable for all 46 population samples, confirming the utility of the method for broad screenings on non-model organisms. Formation of endosperm in all species of Asteraceae was documented. Ratios of endosperm : embryo showed pseudogamous apomixis for Potentilla crantzii (ratio approx. 3), but sexual reproduction for all other species (ratios approx. 1·5).
  
  
  CONCLUSIONS
  The occurrence of apomixis is not correlated to high altitudes, and cannot be readily explained by selective forces due to environmental conditions. The investigated species have probably other adaptations to high altitudes to maintain reproductive assurance via sexuality. We hypothesize that shifts to apomixis are rather connected to frequencies of polyploidization than to ecological conditions.
authors: Department of Systematic and Evolutionary Botany, Faculty of Life Sciences, University of Vienna, A-1030 Vienna, Austria. elvira.hoerandl@univie.ac.at
authors: Elvira
authors: E
authors: Hörandl
authors: Christoph
authors: C
authors: Dobeš
authors: Jan
authors: J
authors: Suda
authors: Petr
authors: P
authors: Vít
authors: Tomáš
authors: T
authors: Urfus
authors: Eva M
authors: EM
authors: Temsch
authors: Anne-Caroline
authors: AC
authors: Cosendai
authors: Johanna
authors: J
authors: Wagner
authors: Ursula
authors: U
authors: Ladinig
mesh_terms: D031162:Achillea / Q000254:growth & development; D000222:Adaptation, Physiological; D000531:Altitude; D031214:Arabis / Q000254:growth & development; D019659:Asteraceae / Q000254:growth & development*; D049919:Erigeron / Q000254:growth & development; D005060:Europe; D036622:Gnaphalium / Q000254:growth & development; D018521:Plant Physiological Phenomena; D031987:Potentilla / Q000254:growth & development; D031947:Ranunculus / Q000254:growth & development; D012100:Reproduction, Asexual; D031995:Saxifragaceae / Q000254:growth & development; D012639:Seeds / Q000254:growth & development