Accumulation of Starch, Protein and the Activities of Invertase and Sucrose ADP (UDP) Glycosyl Transferase in Developing Sorghum vulgare Grains

Abstract

Summary The role of invertase and sucrose ADP (UDP) glucosyl transferase in starch synthesis in the developing grains of Sorghum vulgare Pers. was studied. The level of invertase was high during the initial stages of grain development. There was a close correspondence between the activities of sucrose-ADP glucosyl transferase and sucrose-UDP glucosyl transferase and the rate of starch synthesis suggesting, thereby, an active involvement of these enzymes in starch synthesis. Grain protein was also determined in relation to starch accumulation. The rate of protein synthesis and the flux of soluble sugars continued to increase beyond the stage when the rate of starch synthesis had already started to decline. Exogenously supplied Mg++ through liquid culture stimulated the in vivo incorporation of 14C from [U-14C]-sucrose into starch.