Protein Body Degradation in the Starchy Endosperm of Germinating Sorghum

Taylor, J. R. N., Novellie, L. and Liebenberg, N. v. d. W. 1985.Protein body degradation in the starchy endosperm of germinatingsorghum.—J. exp. Bot. 36: 1287–1295. Transmission electron micrographs of starchy endosperms of germinatingsorghum indicate that the protein bodies are degraded predominantlyby progressive hydrolysis of prolamin from their surface. Theappearance of holes within partially degraded protein bodiesindicates that some internal hydrolysis also takes place. Chemicalanalyses of protein bodies isolated at different stages duringgermination showed that their amino acid composition and electrophoreticpattern remained relatively unchanged during hydrolysis. Theend result of protein body degradation was that the organellescompletely disappeared leaving empty starchy endosperm cells.The protein bodies did not swell prior to or during degradation.This mode of protein body degradation differs from that in germinatingdicotyledonous seeds and in the aleurone layer and embryo ofcereal seeds but was identical to the mode of prolamin proteinbody degradation in the starchy endosperm of germinating riceseeds. Key words: Sorghum bicolor, protein body degradation, prolamin