sentences:  Light intensity is also an important component in determining the temperature of plant organs (energy budget).The light response curve of net photosynthesis (PI curve) is particularly useful in characterising a plant's tolerance to different light intensities.Suboptimal light (shade) typically occurs at the base of a plant canopy or in an understory environment.Shade tolerant plants have a range of adaptations to help them survive the altered quantity and quality of light typical of shade environments.