The resilience of flowers: Corrective reorientation after disturbance

Background/Question/Methods

A flower’s ability to right itself after being knocked over by wind, rain, or animals could be essential to its reproductive success. Such ‘corrective reorientation’ could be tied with certain floral traits, such as floral symmetry (bilateral vs. radial), lifespan (annual vs. perennial), or plant habit (woody vs. herbaceous). Bilaterally symmetric flowers require specialized pollinator handling and thus may benefit more from corrective reorientation than radial flowers. However, corrective reorientation could also simply be a byproduct of the vegetative response to being disoriented (e.g., phototropism). In this study, we experimentally tested for corrective reorientation in 19 bilateral and 26 radial species of flowering plants at the Santa Barbara Botanic Garden and performed analyses on associations between morphological traits and corrective reorientation. We also tested for correlated evolution between floral symmetry and corrective reorientation.

Results/Conclusions

We found that most species experienced corrective reorientation, and that there was no difference between radially and bilaterally symmetric species, nor was there an association between plant lifespan and reorientation. Furthermore, after accounting for phylogeny, we found no evidence of correlated evolution of floral symmetry and corrective reorientation. These results imply that floral reorientation may be equally adaptive for both radially and bilaterally symmetric flowers. Floral corrective reorientation after disturbance appears to be a widespread phenomenon. Future studies are needed to determine whether reorientation corresponds directly with pollinator attraction and reproductive success.