To adapt to climate change, some flowers are darkening their color to protect themselves from the suns radiation, new research shows.
The study suggests that over the past 75 years, the ultraviolet (UV) pigments (紫外线色素) in flowers have increased in response to rising temperatures and the thinning ozone layer (臭氧层). The flowers won't look any different to humans, but insects consider the higher levels of UV pigments as a darker color, which could be confusing when they try to find out colorful flowers to land on.
The UV-absorbing pigments in flowers work like sunscreen and protect sensitive cells from harmful radiation, Matthew Koski, a plant ecologist at Clemson University, says. He and his team hoped to determine if changes in pigments were a result of environmental change-and if so, what are the plants responding to? The team collected dried, pressed plants across North America, Australia and Europe. In total, they studied 1, 238 samples from 42 different species dating back to 1941. Then, using a UV-sensitive camera, they photographed flower petals from each species. Next, they paired the photographs with the historic local temperature and ozone level data from the time the plant was picked to see how the pigment level changed over time.
The researchers found that the changes in pigments differ between species, a result of the flowers structure. Flowers with open, exposed pollen had more UV-absorbing pigments when ozone levels were low and radiation was high. But flowers with pollen surrounded by the petal responded to temperatures, not ozone levels.
As climate change continues to intensify, these changes in flowers color can affect plant-insect interactions. When the whole flowers get darker, insects might miss the flowers entirely. "This has a negative influence on plant reproduction," Koski says.