Photosynthetic Carbon Metabolism: Plasticity and Evolution

Abstract

Carbon metabolism is the important part of the photosynthetic process in that plant green cells convert physical and chemical sources of energy into carbohydrates. Over the last 50 years, knowledge and understanding of carbon metabolism has improved considerably. Photosynthetic carbon metabolism can no longer be explained by a single, invariable cycle. It is no longer restricted to just the chloroplast or even to a single cell. In addition to carbon reduction, nitrogen assimilation, sulphate reduction and other aspects of intermediary metabolism are tightly connected with this process. Like other physiological processes, photosynthesis differs greatly among various plant species and under different environmental conditions. Over the evolutionary history of land plants, selection pressures led to evolution of variants of photosynthetic carbon metabolism namely C4 and crassulacean acid metabolism (CAM) pathways. In this chapter we will focus on the effect of environmental factors on photosynthetic carbon metabolism in order to show the considerable plasticity of this process. In addition, the processes in the evolution of main types of photosynthetic carbon metabolisms will be discussed regarding anatomical, physiological and molecular evidences.