Polyploidy in <i>Odontarrhena bertolonii</i> (Brassicaceae) in relation to seed germination performance and plant phenotype, with taxonomic implications

Odontarrhena bertolonii is an endemic serpentine species of Tuscany and Liguria a model system for nickel-hyperaccumulation research in plants. Phenotypic, genetic karyological variability between populations was previously detected, but existence distribution cytotypes unknown. Accordingly, we examined ploidy level eight from the range tested polyploid fitness hypothesis by analysing relationships with plant phenotype seed germination capacity. Accessions central-western resulted diploid, while those upper Tiber valley were tetraploid. Autopolyploidy via unreduced gametes likely mechanism origin tetraploid Size mass higher seeds, which germinated faster to percentages than diploid ones. Tetraploid plants more robust taller, richly branched inflorescences. Silicle shape size did not differ, style longer tetraploids seeds had larger wing. Overall, these results supported polyploids. Multivariate analysis showed continuous variation consistent differentiation accessions. Taxonomically, at eastern limit can be referred new subspecies, here described as O. subsp. cesalpina.