According to new research by the University of British Columbia (UBC), the bright yellow colour of their flowers not only attract pollinators, but also help the plant regulate water loss.
The dense collection of yellow petals of a sunflower has an ultraviolet (UV) bullseye pattern, invisible to humans but not to most insects, including bees. These bullseye patterns have long been known to improve the attractiveness of flowers to pollinators by increasing their visibility.
Now UBC researchers have found the same molecules that produce UV patterns in sunflowers are also involved in helping the plant respond to stresses such as drought or extreme temperatures, potentially providing clues as to how plants can adapt to different climates.
“Unexpectedly, we noticed that sunflowers growing in drier climates had flowers with larger UV bullseyes, and found that those flowers are able to retain water more efficiently. This suggests that these larger UV bullseyes help plants adapt to these drier environments,” says lead author DrMarco Todesco, who is a research associate at UBC’s Biodiversity ResearchCentre and Department of Botany
