Photoperiod sensitive plants have lower levels of flowering time advancement

Over the last few decades, many plant species have shown significant advances in the date on which they germinate, flush their leaves or begin flowering. However, some species are not changing their phenology and risk falling behind as their competitors and pollinators adapt to the warming climate. In this study, we tested the idea that photoperiod-sensitive species are less likely to advance their flowering time than species without photoperiod sensitivity and look for ways to predict which species are sensitive to photoperiod using phenology and two life history characteristics. We found that on average, plants that respond to long daylengths (over 12 hours) are not changing their flowering time as rapidly as plants that respond to short daylengths (under 12 hours) or plants with no photoperiod requirements. It is not possible to predict which species are sensitive to photoperiod with phylogeny, but herbs and annual species are more likely to be photoperiod-sensitive than are woody or perennial species. In the past, photoperiod sensitivity may have helped plants ignore unseasonal weather extremes. Our findings suggests plants with long-day photoperiod requirements are responding differently to climate change than other plants.

Methods
Data was compiled from an ISI Web of Science keyword search and additional papers and reference books were added by looking through references of those identified in the search, as well as highly cited literature reviews on photoperiod sensitivity. Data was manually entered after each source was read and species names were checked against The Plant List (http://www.theplantlist.org/).