Plant Biol. (2020)

Polyploidy, the condition of having more than two complete sets of genomes, has been an important evolutionary mechanism for flowering plant diversification. Polyploids often occur in more variable or extreme habitats than their diploid progenitors (those with two chromosome sets), leading to the hypothesis that the expanded physiological and morphological variation found in polyploids may make them more competitive under changing climates.

Credit: NSP-RF / Alamy Stock Photo

Amelia Stevens and co-authors in Canberra, Australia, studied diploid and tetraploid kangaroo grass (Themeda triandra) plants to investigate the influence of within-species ploidy variation on early establishment traits. Compared with diploid plants, tetraploids generally had heavier seeds and a higher proportion of dormant seeds, and they developed heavier and taller seedlings. Tetraploid seeds also had lower germination under drought and temperature stress. Together, this suggests that tetraploid seeds may be more resilient to long unfavourable periods, and quicker to establish when conditions are good. These results have important implications for current grassland restoration efforts, as well as for the continued fitness of this species and grassland ecosystems under long-term climate change.