Abstract
We studied the within-population genetic structure and the clonality extent of Viola calaminaria, a rare endemic species of calamine soils, by means of RAPD markers in two populations (one recent and one ancient) with expected harsh and heterogeneous heavy-metal stress. At a very local scale (0.2-3 m), clonal propagation was detected in both populations, but the levels of clonal diversity were high (number of genets/number of ramets sampled = 0.9 [recent] and 0.76 [ancient]) and the maximal observed extension of the clones was 0.4 m. This indicated that clonality is not, for the species, an important mode of propagation and that clonal growth cannot be interpreted as a strategy for propagating or perpetuating adapted genotypes under harsh ecological constraints. Spatial autocorrelations revealed a significant (P < 0.001) negative value of correlogram slope in the two populations even when a single individual per clone was considered (i.e., analysis at the genet level). We conclude that spatial genetic structure at a very local scale reflects limited gene flow due to restricted seed dispersal rather than variation in clonal pattern in response to environmental heterogeneity. At a larger scale (2-30 m), spatial autocorrelations revealed a positive (P < 0.001) correlation at < 3 m and a random pattern at larger distances for the two populations. This suggested a patchy distribution of the genetically linked individuals associated with a disrupted pattern at a longer distance probably due to gene flow by pollen dispersal and a seed bank effect. The implications for the conservation of V. calaminaria are discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.