Light spectral quality, phytochrome and plant competition.

The light environment experienced by plants in natural vegetation is strongly dependent upon interactions with neighbors. For plants in dense stands, reduced irradiance can lead to reductions in growth and fitness. Spectral light quality is also altered beneath a leaf canopy, and can serve as an important signal of competition for light. Recent physiological studies indicate that plants can perceive the quality of light reflected from neighbors as an accurate predictor of future competition, and respond morphologically even before they are directly shaded. These findings have important implications for plant population biology, and provide a valuable opportunity for the study of adaptive plasticity.