Which of the following signals indicates shade to a plant?
A) light quantity
B) blue light
C) far-red light
D) red light

Question

Quizplus · Accepted Answer

Far-red light is the signal that indicates shade to a plant. When a plant is in shade, it receives less red light and more far-red light due to the filtering effect of the surrounding foliage. The ratio of red to far-red light is perceived by the plant as a shade signal, triggering a series of growth responses, such as elongation of the stem and increase in leaf size, that allow the plant to reach for more light. Light quantity, blue light, and red light do not specifically indicate shade to a plant.

Which of the Following Signals Indicates Shade to a Plant