`Sugar Partitioning and Sink-Source Modification in Plants

Abstract

Solar energy is converted to chemical energy and stored as assimilates through a phenomenon called photosynthesis. Plant leaves function as the principle site of resource acquisition by utilizing the free energy captured via photosynthesis for the reductive assimilation of oxidized forms of carbon into carbohydrates. Photosynthetic carbon fixation provides vital energy for metabolism and precursors for all other biosynthetic pathways in the plant. Most of these precursors are required for biosynthesis of amino acids that form the building blocks for many compounds in plants. The regulation of assimilate partitioning in leaves is considered as allocation of carbon between sucrose and starch synthesis, storage, and export, and carbohydrate metabolism [1,2]. Sucrose is the most important metabolite in this system of resource allocation because it is generally the major end product of photosynthetic carbon metabolism and, in most plants it is the predominant form of carbon transported to the heterotrophic tissues [3-5]. Sucrose allocation between tissues is a fundamental process in all multicellular organisms. Indeed, as much as 80% of the carbon acquired in photosynthesis is transported in the plant’s vascular system to import-dependent organs [6].