Natural variation in phytochrome signaling

The phytochromes, photoreceptors sensitive to red and far-red Eight, are cr itical for sensing foliage shade, canopy breaks, and neighbor proximity. A combination of molecular genetic, evolutionary, and ecological techniques a re being used to understand how phytochromes function in the natural enviro nment. We discuss studies on the adaptive value of phytochrome mediated pla sticity, as well as the role that variation in phytochrome expression and f unction might play in allowing plants to adapt to unique light environments . Continued study of phytochrome signaling variation may reveal how natural selection acts at the molecular level.