Deeper purple: how temperature affects pollen colour

There are plenty of studies on how petal colour varies, but new research looks at differences in the performance of pollen under varied environmental conditions based on its colour. In the study of the North American herb Campanula americana, published in New Phytologist, investigators found that differences in heat tolerance among pollen colour variants could contribute to geographic variation in pollen pigmentation across the USA.

Image: Figure 1a: Pollen colour variation in Campanula americana varies from white to deep purple.
Figure 1a: Pollen colour in Campanula americana varies from white to deep purple.

The study revealed that western populations have darker purple pollen than eastern populations, where white to light-purple pollen is more common. Western populations also experience more extreme high temperatures and elevated UV-B irradiance. Experimental manipulation of temperature and UV revealed that dark pollen performs better than light pollen under higher temperatures, but not elevated UV.

“In light of global change, temperature stress could be an increasingly important selective agent on pollen pigmentation” said co-author Dr. Matthew Koski, of the University of Virginia. The research provides an important insight into how climate change might affect flower colour and interactions between flowers and pollinating insects.

Read the paper: Koski, M.H. and Galloway, L.F. (2018) Geographic variation in pollen colour is associated with temperature stressNew Phytologist. doi: 10.1111/nph.14961


Mike Whitfield (@mgwhitfield)
Development Coordinator
New Phytologist