Biomasses, starch content, cell membrane leakage and phenology of established diploids and tetraploids and synthetic neotetraploids of Jasione maritima var. maritima

Polyploidy is a pervasive phenomenon in nature and has significantly
contributed to the adaptive evolution of plants. The conditions necessary
for the spread of neopolyploids in populations of the diploid progenitor
are limited; however, the superior competitive ability of neopolyploids
may promote its establishment. Here, we assess the contribution of
polyploidisation to the divergence of plant traits affecting competitive
response, which could explain the successful establishment and current
geographic distribution of polyploids. We conducted an intraspecific
competition experiment using diploids, neotetraploids and established
tetraploids of Jasione maritima var. maritima to determine whether
cytotypes differ in phenological, growth and physiological traits and
competitive response. Cytotypes respond differently under different
competition scenarios with implications for cytotype establishment and
distribution. Competition impacted all cytotypes, but neotetraploids were
least affected by competition, and the tetraploids were the most impacted.
Thus, competitive advantage may have contributed to the displacement of
diploid populations and colonisation of new areas by neotetraploids but
might have been lost afterwards. Evolutionary changes after
polyploidisation have also been detected, and tetraploids invested more in
belowground biomass, suggesting that root development might also play a
role in colonising southernmost locations. Interestingly, diploids and
both tetraploids seem to have different life strategies, the first
investing in growth while the latter investing in reserves for the next
season. Overall, polyploidisation seems to provide immediate changes that
confer an advantage under competition that, together with other factors,
may have allowed the establishment of neotetraploids.