The light-sensing molecules that tell plants whether to germinate, when to flower and which direction to grow were inherited millions of years ago from ancient algae, finds a new study from Duke University.
The findings are some of the strongest evidence yet refuting the prevailing idea that the ancestors of early plants got the red light sensors that helped them move from water to land by engulfing light-sensing bacteria, the researchers say.
The light-sensing molecules that tell plants whether to germinate, when to flower and which direction to grow were inherited millions of years ago from ancient algae, finds a new study from Duke University.
The findings are some of the strongest evidence yet refuting the prevailing idea that the ancestors of early plants got the red light sensors that helped them move from water to land by engulfing light-sensing bacteria, the researchers say.
The results appear online in Nature Communications.
“Much like we see the world through our eyes, plants ‘see’ the world through light-sensitive proteins in their leaves called photoreceptors,” said Duke postdoctoral researcher Fay-Wei Li.
Photoreceptors monitor changes in the direction, intensity, duration and wavelength of light shining on a plant, and send signals that tell plants when to sprout, when to blossom, and how to bend or stretch to avoid being shaded by their neighbors.
“Light is what gives plants the energy they need to survive,” Li said. “But light is constantly changing with the time of day and the seasons and the surrounding vegetation. Photoreceptors help plants determine if it’s summer or winter, or if they’re under the canopy or out in the open.”
A group of photoreceptor proteins called phytochromes enable plants to detect and absorb light in the red and far-red regions of the light spectrum, the main wavelengths of light that plants use for photosynthesis.
Just 20 years ago, researchers discovered that plants weren’t the only living things with phytochromes. Thanks to DNA sequencing, scientists started uncovering similar genes in cyanobacteria, tiny green bacteria that live in oceans, rivers and streams.
Marine Phytoplankton image via Shutterstock.
Read more at Duke University.
