Poster: Temperature Responses

Abs # 181: Irreversibility of Chilling Injury in Zucchini Squash (Cucurbita pepo L.)

Presenter:	Martinez-Tellez, Miguel A., norawa@cascabel.ciad.mx
Authors	Martinez-Tellez, Miguel A. (A)   Balandran-Quintana, Rene R. (B) (A)  Mendoza-Wilson, Ana M. (A)   Vargas-Arispuro, Irasema  (A)   Gardea, Alfonso A. (A)
Affiliations:	(A): Centro de Investigación en Alimentación y Desarrollo, A.C. (B): Universidad Autónoma de Chihuahua

Zucchini fruits were subjected to 2.5º or 10ºC for 16 d, followed by transfer to 20ºC for 24 h in order to evaluate the relationship between ripening pattern, measured as CO₂ evolution and ethylene (C₂H₄) production, and metabolic heat production (q). Chilling injury (CI) visible symptoms were evident after 8 d at 2.5ºC, but none were recorded on fruits kept at 10ºC. In fruits held at 10ºC, q, C₂H₄ production and CO2 evolution diminished in the course of 16 d, whereas in those at at 2.5ºC CO2 evolution showed an early burst peaking at 8 d. Both C₂H₄ production and q also showed a burst at 2.5ºC but they started at 4 and 8 d, respectively, and peaked at 12 d. The results showed that irreversibility of chilling injury in zucchini could occur long before the appearance of visible symptoms, but the metabolic activity accompanying the irreversibility process was not noticeable by calorimetry. Key words: chilling injury; zucchini squash; Cucurbita pepo L.; calorimetry; plant heat evolution; metabolic heat rates; cold signaling