2.6. Assay of cell wall softening enzymes:
polygalacturonase (PG), pectin methylesterase (PME), pectate lyase (PL) and cellulase (CX) Fruit ripening is closely related to the cell wall softening related enzymes including PG, PME, PL and CX. The activities of these enzymes were determined as described by Guo et al. (2014) and Zhang et al. (2010).