Additional green light induces shade response symptoms in Brassica rapa as evidenced by increased lateral root spread

In some plant species, green light (500 to 570 nm) has been shown to act as a shade signal, which stimulates non-photosynthetic photoreceptors to initiate a response that promotes shading symptoms, including lateral root formation. No studies to date have examined whether green light induces shading symptoms in Brassica rapa specifically. Here, we report increased hypocotyl length, root width, and increased width:depth ratio of root architecture in plants grown under additional green light compared to red and blue light, and white light alone. Results indicate that green light acts as a shade signal in B. rapa to induce shading symptoms, including wider roots.