Physiological and biochemical changes associated with cotton fibre development. VII. Carbohydrate metabolism

The relationship between growth and some enzymes of carbohydrate metabolism in developing cotton fibre were studied. Two respiratory pathways of gluco se oxidation i.e. oxidative pentose phosphate pathway (OPPP) and glycolysis operates in the elongating cotton fibres and the extent of their operation varies with the demand for respiratory products. In this respect, hexokina se, G-6-PDH, 6PGDH, and MDH show increased activities during the period of rapid cell elongation and decreased activities when rate slows down. The co nversion of PEP to malate and/or via a transhydrogenase system consisting o f enzymes PEPC, MDH and NADP-MDH(d) may play a significant role in carbohyd rate compartmentation of developing cotton fibre. As the rate of fibre grow th slows down, a decline in enzyme activities, points to a shift in metabol ic priorities.