Biochemical Aspects of Shoot Differentiation in Sugarcane Callus: II. Carbohydrate Metabolizing Enzymes

Abstract

Summary Developmental patterns of the key EMP and PP pathway enzymes were investigated in shoot forming and non-shoot forming sugarcane callus. The activity of phosphoglucose isomerase (PGI), aldolase, pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PgD) followed identical developmental patterns in the two programmes for the first 8 days of culture. As compared with the non-shoot forming callus, the shoot forming callus was characterized by higher activity levels of these enzymes at all times during the culture period. The PP pathway enzymes i.e. G6PD and 6PgD, showed rapid increase in activity during the preemergence (day 4 – 8) period of shoots in the shoot forming callus. During the corresponding period the activity of the EMP pathway enzymes i.e. PGI, aldolase, and PK in the shoot forming callus declined. The activity of both the EMP and the PP pathway enzymes in the shoot forming callus increased during the postemergence period (day 8 – 10) of shoots. Higher activity levels of the EMP and the PP pathway enzymes in the shoot forming sugarcane tissue is indicative of high generation of energy molecules, reducing power and pentose sugars, vital for energy dependent reactions and the synthesis of nucleic acids during shoot differentiation.