Plants’ ability to sense red light key to life on land
(July 28, 2015) 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.”