Correlations of polyploidy and apomixis with elevation and associated environmental gradients in an alpine plant

Abstract

We are presenting a study on geographical parthenogenesis, an enigmatic and much disputed phenomenon. Based on a large sampling of natural populations of Ranunculus kuepferi, it is the first quantitative, population-based assessment of mode of reproduction throughout the Alps to test for correlations to elevation and to geographical distance patterns. Surprisingly, we found a high variance in the modes of reproduction among cytotypes and can give the first evidence of apomixis in diploid natural populations. Further, a significant correlation of ploidy to elevation was found, as well as the correlations of mode of reproduction to environmental gradients.

Difference in reproductive mode rather than ploidy explains niche differentiation in sympatric sexual and apomictic populations of Potentilla puberula

“…Drought was identified as a factor driving the pattern in Draba (Price, ), Antennaria (Bierzychudek, ), Bidens (Crowe & Parker, ), Paspalum intermedium (Karunarathne et al, ), and the Ranunculus auricomus complex (Paule et al, ). The opposite pattern, however, was found in this study: Sexual P. puberula prevailed at drier sites, a tendency also observed in Ranunculus kuepferi (Schinkel et al, ). This might be explained by the negative effects of rainy weather on pollinators’ behavior (Puškadija et al, ), which avoid flying under the rain or foraging on wet blossoms.…”

“…Studies dealing with these issues often remained inconclusive, due to limitations inherent to the studied taxa, such as lack of cytotypic variation within reproductive mode or different evolutionary history of sexuals and apomicts (see Supporting Information Table A5 in Appendix for a review of ecological studies in amphi‐apomictic systems). For instance, Schinkel et al, () found apomictic individuals in three pure diploid populations of Ranunculus kuepferi , which shared the ecological site conditions of co‐occurring sexuals. However, their number was not high enough to prove that polyploidy was a requirement for range expansion.…”

“…Such a geographical parthenogenesis is often linked to ecological differentiation among sexual and asexual populations, a phenomenon defined as “ecological parthenogenesis” (Bell, ). Specifically, asexuals tend to (a) inhabit cooler or drier habitats and (b) have broader ecological ranges (e.g., in Erigeron, Noyes, Gerling, & Vandervoort, ; Paspalum intermedium , Karunarathne et al, ; Ranunculus auricomus , Paule, Dunkel, Schmidt, & Gregor, ), albeit examples showing opposite trends (e.g., asexuals inhabit more humid habitats in Limonium , Caperta et al, , and Ranunculus kuepferi , Kirchheimer et al, ; Schinkel et al, ) indicate the idiosyncratic response of taxa.…”

The “Polyploid Hop”: Shifting Challenges and Opportunities Over the Evolutionary Lifespan of Genome Duplications

“…It has long been recognized that asexual reproduction (vegetative propagation and agamospermy) and WGD are correlated, with polyploids displaying elevated rates of asexual propagation compared to diploid relatives (Manning and Dickson, 1986;Schinkel et al, 2016;Herben et al, 2017). Such a reproductive strategy may even confer short-term benefits.…”

Characterization of diverse ploidy in the arctic‐alpine Arenaria ciliata species complex (Caryophyllaceae) using shoot meristem staining and flow cytometry analysis of archived frozen tissue

“…This phenomenon has long been viewed as an outcome of selective pressure during postglacial recolonization, where polyploid identities (combined in part with apomixis) are seen to facilitate adaptive leading‐edge population dispersal into novel habitats (Bliss ), and there is now some empirical support for this proposition (Schinkel et al . ).…”