Invisible flower colors help plants survive

Some flowers have “bulls eyes” painted on them in ultraviolet which are Invisible to us, but visible to insect pollinators. Besides guiding insects to their sweet spot, ultraviolet coloration may play other important roles.  

New research by scientists at Clemson University looked into how these “invisible” colors help plants adapt to changing conditions, including climate change. The research, published in the journal Evolution , was focused on the yellow flowers of silverweed (Argentina anserina).     

The scientists examined the pigment in the plant’s flower petals at various elevations in Colorado to determine their role in pollination. 

“I’ve always been fascinated with how [color variation of flowers] arises and how it evolves and what factors drive the evolution of color variation…so I got interested in thinking about how we perceive color versus how the organisms that interact more frequently with flowers perceive color,” said Professor Matthew H. Koski, who led the research.

“Insects – pollinators, for example – see in the ultraviolet spectrum. So, flowers that reflect or absorb ultraviolet wavelengths give (to pollinators) the perception of different colors that we can’t see. I’ve been fascinated with uncovering what these UV signals might be doing functionally with respect to pollination. When I thought about the trait of interest in ultraviolet absorption, it is biochemistry. It’s a biochemical trait that leads to different perceptions of UV absorption and reflectance.”

The researchers discovered that the flowers had UV reflecting pigments at their tips and UV absorbing chemicals at the base of their petals. At higher elevations there were more UV absorbing chemicals than at low elevations. The scientists say this reveals the plant’s plasticity because it shows change depending on the environment. 

“What’s important about plasticity is, when we think about climate change and global change, plasticity is one mechanism by which natural populations can respond really rapidly to changing climates and persist under those climates,” said Professor Koski. “The process of evolution, where you’re getting changes in the genetic code over time, is thought to proceed more slowly than just responding plastically to environmental change.”

The study authors believe that more research into this field could be useful in understanding how plants change due to climate change and potentially be useful for crops as well as wild plants. 

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By Zach Fitzner, Earth.com Staff Writer