The biochemical basis of differential ripening in mango.
Lazan H., Ali Z. M., Talkah Z., Soh J. S.
Author Affiliation: Department of Botany, Faculty of Life Sciences, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
: 500-509
Abstract : A characteristic of mango fruits is the differential ripening of the inner mesocarp before the outer. Various biochemical indicators of cell wall metabolism in cv. Harumanis fruits stored at 25°C and 98% RH for various lengths of time (i.e. polygalacturonase and ?-galactosidase) together with respiratory metabolism (i.e. NADP-malic enzyme, PEP-carboxylase and organic acid and sugar concentrations) all suggested that the inner mesocarp is more metabolically active than the outer mesocarp. Polygalacturonase was differentially distributed in the mesocarp tissue and its activity was positively correlated with tissue softness, whether caused by ripening or position within the mesocarp. The contents of ?-galactosidase and PEP-carboxylase were also differentially distributed and their activities increased more rapidly in the soft inner than in the firm outer tissue. The inner tissue also contained increasingly more NADP-malic enzyme than the outer tissue and a correspondingly lower amount of malate during ripening. The higher overall metabolic activity in the inner tissue suggests that the ripening process is initiated there.