Opinion. Location matters: Canopy light responses over spatial scales ($) (Trends Plant Sci)

Light is arguably one of the most important signals recognized by plants. Not surprisingly, plants exhibit a wide range of light responses, ranging from cell-specific to large-scale. Küpers et al. review these responses, with an emphasis on their spatial scales. For example, the production of extrafloral nectar from the leaf and leaf lamina growth inhibition are both local responses, whereas root development and floral transition involve inter-organ signalling including long-distance transport of proteins that convey light information (e.g., HY5 and FT). Even responses that appear seemingly local, such as hypocotyl elongation and petiole hyponasty, “are largely regulated by distal light-quality signals in the cotyledons and leaf tip, respectively.” Trends Plant Sci. 10.1016/j.tplants.2018.06.011