Effect of low temperature storage and ethylene removal on ripening and gene expression changes in avocado fruit.
Zamorano, J. P.; Dopico, B.; Lowe, A. L.; Wilson, I. D.; Grierson, D.; Merodio, C.;
Postharvest Biology and Technology Year: 1994 Vol: 4 Issue: 4 Pages: 331-342 Ref: 21 ref.
1994
บทคัดย่อ
ABSTRACT :
Changes in physiological parameters and in the RNA population from avocado fruits (cv. Hass) stored under different conditions were analysed. Storage at low temperatures (3 or 7 deg C) markedly reduced respiration and ethylene production rates. Fruit softening was delayed at 7 deg , while fruits stored at 3 deg did not soften during long-term storage (56 days). CO2 levels in the atmosphere surrounding fruits treated with a commercial ethylene absorbent were slightly depressed at 7 deg and slightly higher at 3 deg , compared with storage without the absorbent. Ethylene production rates appeared not to be affected by ethylene absorption. Changes in the expression of several mRNAs, detected by in vitro translation of RNA during ripening at 20 deg (increases in polypeptides of MW 95, 72, 65, 55, 50, 41 and 40 kDa and decreases in those of MW 54 and 42 kDa) were delayed or blocked at low temperatures. Under these conditions, changes in mRNAs encoding 2 polypeptides (MW of 80 and 42 kDa) were found to
be opposite to those observed during normal ripening. mRNAs for other polypeptides (MW of 90, 69, 47 and 45 kDa) showed variations in level depending on storage conditions. A few mRNAs were observed only during cold storage (MW of 62, 60, 58, 57, 56 and 47 kDa) and could be related to cold stress or acclimatization of the fruits. The results obtained suggest that the main effect of low temperatures in avocado fruits is a delay or blockage in the expression of specific genes related to ripening. The effect of the ethylene absorbent was mainly noted in the polypeptide pattern for translated mRNAs, in which most of the changes observed for non-treated fruits were delayed.