Sugar Accumulation Cycle in Sugar Cane. II. Relationship of Invertase Activity to Sugar Content & Growth Rate in Storage Tissue of Plants Grown in Controlled Environments

Immature internodes of sugar cane contain an acid invertase with optimum activity between pH 5.0 and 5.5 (1,2). The level of this enzyme shows marked seasonal variation, being high when growth is rapid and low otherwise. Acid invertase is absent from mature internodes of sugar cane varieties with a high capacity for sugar storage, which instead contain a neutral invertase with optimum activity at pH 7.0. In this paper, we report measurements of acid and neutral invertase activities, rates of elongation of internodes, and sugar contents of plants which were subjected to different temperature and water regimes in controlled environment greenhouses.