Acid Scarification and Protein Synthesis during Seed Germination1

Abstract

AbstractIndian ricegrass [Oryzopsis hymenoides (Roem. and Schult.) Ricker] seeds exhibit an intense seed coat dormancy which is relieved by acid scarification. This study examined the influence of exogenous hormonal compounds, gibberellin A3 (GA3) and abscisic acid (ABA) and acid scarification on the early protein synthesis of these seeds. Hormonal applications failed to alter 14C‐leucine incorporation or to change the levels of amino acid pool size or soluble protein during the first 72 hours of soaking of intact seeds. However, GA3 enhanced while ABA lowered the amino acid and soluble protein levels in scarified seeds. The incorporation of relatively large amounts of 14C‐leucine into proteins occurred at 24 hours after soaking in intact seeds while no increase was detected in scarified seeds until 48 hours, a period when germination had already occurred. Soluble proteins were reduced 60 % following acid scarification compared to intact seeds and seed exudates increased with increased scarification time. These results demonstrate a profound effect of acid scarification on the seed which is manifested by delayed protein synthesis, reduced protein level, and increased leaching of electrolytes.