The color of light primarily reflected by chlorophyll-containing plant tissue is green. Chlorophyll absorbs blue and red light relatively strongly but absorbs green wavelengths less efficiently, so more green light returns to our eyes.
This color is produced by chlorophyll molecules embedded in photosynthetic membranes inside chloroplasts. The pigment captures useful light energy and transfers that energy into the reactions of photosynthesis, helping convert carbon dioxide and water into carbohydrates while releasing oxygen.
A common simplification is to say that chlorophyll itself simply reflects green light. More precisely, chlorophyll is a poor absorber of green light, and green light is diffusely reflected or scattered by the leaf’s internal structures, including cell walls and other tissues. The result is that chlorophyll-rich leaves appear green.
Plants contain several related chlorophylls. Green plants use chlorophyll a and chlorophyll b, which have overlapping but slightly different absorption spectra. Leaves can change color when chlorophyll breaks down in autumn, revealing yellow carotenoids or, in some species, allowing red and purple anthocyanins to become more visible.