Photomorphogenesis and photoperiodism in plants

Abstract

Plants depend on light as their main source of energy. However, light is also an important source of information for plants, and changes in the nature of the light reaching a plant can signal seasonal change, potential and actual competition by shading, proximity to the soil surface of roots and seeds, and potential photodamage. This chapter describes how plants detect and respond to their light environment. Plants possess several types of photoreceptors that collectively allow them to detect variation in a number of different light parameters including its spectral composition, irradiance, direction, and daily duration. Signaling pathways initiated by activation of these photoreceptors allow the plant to make adjustments to developmental processes such as germination, stem elongation, chloroplast development and orientation, stem and root bending, and the initiation of flowering. Recent molecular genetic analysis in the main higher plant model, Arabidopsis thaliana, has brought rapid progress to our understanding of the molecular nature and ecological significance of plant responses to light. © 2008 Springer Science+Business Media, LLC.