1 . It turns out that sunflowers are more than just a pretty face: the ultraviolet (紫外线的) colours of their flowers not only attract pollinators (传粉者), but also help the plant regulate water loss, according to new research.
The yellow sunflower is a familiar sight, but it’s hiding something from the human eye — an ultraviolet bullseye (靶心) 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.
“Unexpectedly, we noticed that sunflowers growing in drier climates have flowers with larger ultraviolet bullseyes, and found that those flowers are able to keep water more efficiently. This suggests that these larger ultraviolet bullseyes help plants adapt to these drier environments,” says Dr. Marco Todesco.
Dr. Todesco and his colleagues grew almost 2,000 wild sunflowers of two species at the university in 2016 and 2019. They measured the sunflowers’ ultraviolet patterns, and analyzed the plants’ genes, and found that wild sunflowers from different parts of North America had ultraviolet bullseyes of very different sizes.
Larger floral ultraviolet patterns that have more of these compounds could help reduce the amount of water loss from a sunflower in environments with lower humidity (湿度), preventing too much water loss. In humid, hot environments, smaller ultraviolet patterns would promote the water loss, keeping the plant cool and avoiding overheating.
Sunflowers are planted for various purposes, including sunflower oil production, a roughly $20 billion industry in 2020. This research could help add to knowledge about how to attract pollinators, potentially increasing crop yields, says Dr. Todesco. “This work also helps us understand how sunflowers, and potentially other plants, better adapt to different areas or temperatures, which could be important in a warming climate.”
1. What do we know about sunflowers?| A．They don’t need pollinators. |
| B．Their flowers have special functions. |
| C．Their flowers can drive the insects away. |
| D．They can be grown in extremely cold areas. |
| A．They analyzed 2000 kinds of sunflowers. |
| B．They planted sunflowers to carry out research. |
| C．They travelled to different parts of South America. |
| D．They helped people in North America plant sunflowers. |
| A．Positive. | B．Doubtful. |
| C．Negative. | D．Critical. |
| A．A Hidden Function of Flowers of Sunflowers |
| B．Researchers Found a New Species of Sunflower |
| C．Sunflowers Can Change the Colours of Sunshine |
| D．Ultraviolet Bullseye Patterns Attract More Insects |
