Investigation of the Physiological Changes Behind the Range Expansion of the Polyploid Hybrid, Polystichum scopulinum

Abstract

In plants, polyploidy has been thought to play a key role in evolution as it can generate more genetic variation. However, we do not have a strong understanding of how polyploidy affects physiology, which limits our understanding of trait evolution and species ecology. To investigate this, we focused on an allopolyploid hybrid, Polystichum scopulinum, to understand how polyploidy may have enabled its range expansion in relation to its progenitors, P. imbricans and P. lemmonii. We show that the leaf thickness (LT) of the polyploid hybrid is similar to P. imbricans’s LT but significantly higher than P. lemmonii’s LT, and that the hybrid’s leaf hydraulic conductance (Kleaf) is significantly lower than both progenitors. These results suggest that P. scopulinum’s physiological differences may be linked to differences in its ecology.