Sunflowers’ Invisible Colours Help Them Attract Bees and Adapt to Drought

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It turns out sunflowers are more than just a pretty face: the ultraviolet colours of their flowers not only attract pollinators, but also help the plant regulate water loss, according to new UBC research.

It turns out sunflowers are more than just a pretty face: the ultraviolet colours of their flowers not only attract pollinators, but also help the plant regulate water loss, according to new UBC research.

The dense collection of yellow petals of a sunflower (technically an ‘inflorescence’, or collection of many flowers) is a familiar sight, but it’s hiding something from the human eye: 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, in a new paper published today in eLife, potentially providing clues 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 Dr. Marco Todesco, a research associate at UBC’s biodiversity research centre and department of botany.

Read more at University of British Columbia
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