Cell Wall Degrading Enzymes and the Softening of Senescent Strawberry Fruit

The changes in enzyme activity occurring during the ripening of strawberry fruit on the plant and the development of senescence after picking have been studied. Pectinesterase is found to increase from the green to early ripe stages but to decrease during the senescent “overripe” stage. Polygalacturonase and polymethylgalacturonase activity were not found. A C x ‐type cellulolytic activity was observed in ripe fruit and increases in the “over‐ripe” fruit. These observations tie used to provide a possible explanation for the loss of firmness after strawberry fruit has been picked and becomes senescent.