Fruit maturity and calcium affect chilling requirements and ripening of 'd'Anjou' pears.

摘要

D'Anjou [Beurre d'Anjou] pear (Pyrus communis) trees were sprayed with 0 or 32.3 mM CaCl2 during fruit development at 55, 86, 125 and 137 days from full bloom and harvested at 85% (immature), 100% (mature), and 110% (overmature) maturity stages. Thefruits were stored in air at -1deg C for several periods to determine the effect of CaCl2 treatments on chilling requirement to accomplish ripening during 11 days at 20deg C. Immature or mature unsprayed fruits required 55 days, while the overmature fruits required 40 days at -1deg C to gain the capacity to produce ethylene during ripening at 20deg C. Calcium sprays increased flesh firmness at harvest by 15 N, fruit Ca concentrations by an average of 0.01 mg g-1, fresh mass basis, and the chilling requirements byat least 15 days. Unsprayed immature fruits contained more Ca than the sprayed mature or overmature fruits, but their chilling requirement was similar. These results suggest that high Ca concentrations may increase the chilling requirement of d'Anjou pears in a developmentally related manner.