Light and Temperature Adaptation
Photosynthetic adaptation may be defined as environmentally induced adjustments in physiology, anatomy, and morphology that enable a plant to photosynthesize more efficiently in a new environment. Adaptation to high irradiance often results in higher light-saturation ranges for photosynthesis and greater photosynthetic rates per unit leaf area at light saturation. Adaptation to low irradiance, on the other hand, may result in lower light-saturation ranges, lower light-compensation points, lower maximum photosynthetic rates, and lower dark-respiration rates. This chapter deals with photosynthetic adaptation to both light and temperature. It considers a number of examples of photosynthetic light adaptation and examine some of the mechanisms accounting for it. The chapter shows how changes in leaf characteristics at the organ, cellular, and subcellular level contribute to the observed effects of irradiance on gas exchange characteristics. It points out various leaf characteristics that are modified in response to irradiance during growth.