Plants can turn their roots into virtual flashlights to promote new growth by piping sunlight down their stems, New Scientist reports. Light is reflected down the stem and through the roots by receptors called phytochromes, researchers say in their paper in the journal Science Signaling. The process is similar to how fiber optic cables transmit the light signals that allow you to stream your favorite shows online. (The way this happens is a bit more complicated, but this video helps.) The scientists detected the reflective properties of the phytochromes—which activate proteins that promote growth—by putting a light source at the stem and a sensor at the roots. But unlike the light glowing from your laptop, the light moving through the root system is far too dim for soil-dwelling critters to notice or for bacteria to use for photosynthesis.