The pseudometallophyte Noccaea caerulescens is an excellent model to study adaptation to heterogeneous environments, as it grows both on normal and on heavy-metal-rich, toxic soils. Information on its mating system is limited, despite the potential impact on its evolution and demography.
Mousset et al. measured selfing rates using robust genetic estimation methods in five metallicolous and five non-metallicolous populations in Southern France, and replicated this measure for different reproductive seasons. They find consistently higher selfing rates, and lower effective sizes, in non-metallicolous populations than in metallicolous populations and discuss how it might constrain adaptation to polluted and non-polluted sites.
Mathilde Mousset, Patrice David, Christophe Petit, Juliette Pouzadoux, Clémence Hatt, Élodie Flaven, Ophélie Ronce, Agnès Mignot, 2016, 'Lower selfing rates in metallicolous populations than in non-metallicolous populations of the pseudometallophyteNoccaea caerulescens(Brassicaceae) in Southern France', Annals of Botany, vol. 117, no. 3, pp. 507-519 http://dx.doi.org/10.1093/aob/mcv191