Storage temperature and fruit calcium alter the sequence of ripening events of 'd'Anjou' pears

Pear trees (Pyrus communis L.), cv, d'Anjou, received foliar applications of X-77 surfactant and 32.3 mM CaCl2 at 55, 85, 125, and 137 days after full bloom (DAFB) and fruit were harvested at: 147 DAFB. Samples of fruit mere stored in air either at 20 degrees C continuously or at 5 or 10 degrees C for several periods, then transferred to 20 degrees C, to determine the effects of storage temperature and CaCl2, treatments on the development of the ethylene climacteric and flesh firmness loss. Control fruits held continuously at 20 degrees C required 70 days for the onset of climacteric ethylene production, which commenced when firmness had decreased to approximate to 20 N. Calcium-sprayed fruit required 80 days at 20 degrees C before the rise in ethylene and resisted softening for approximate to 50 days. Regardless of calcium treatment, pears stored at 5 or 10 degrees C required only 40 days to produce climacteric ethylene; fruit softening and internal ethylene concentration after storage at 10 degrees C were intermediate between those of fruits stored at 5 and 20 degrees C. Calcium application did not alter the sequence of ripening events.