Starch biosynthesis leaves

Starch is bio synthesized in plant organelles. In leaf or transitory starch, the organelles are chloroplasts and in storage starch in seeds, tubers, stems, and roots, the organelles are amylo-plasts. The process of starch biosynthesis is divided, for convenience of discussion, into three steps (1) initiation, (2) elongation, and (3) termination, and for amylopectin, a fourth step, branching. 

The leaf ADP-Glc PPase is highly sensitive to 3-PGA, the primary product of CO2 fixation by photosynthesis, and to Pi as seen in Table 2. Thus, it has been suggested that these compounds play a significant role in vivo in regulating starch biosynthesis in higher plants and and in regulating glycogen... 

J. Preiss H. P. Ghosh J. Wittkop, Regulation of the Biosynthesis of Starch in Spinach Leaf Chloroplasts In Biochemistry of Chloroplast, T. W. Goodwin, Ed. Academic Press New York, 1967 Vol. 2, pp 131-153. 

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