The relationship between preformed antifungal compounds, disease resistance of citrus fruits and various postharvest treatments.
Ben-Yehoshua, S.; Fang, D. Q.; Kim, J. J.; Rodov, V.;
Postharvest physiology, pathology and technologies for horticultural commodities: recent advances. Proceedings of an international symposium held at Agadir, Morocco, 16-21 January 1994. Year: 1995 Pages: 407-413 Ref: 13 ref.
1995
บทคัดย่อ
ABSTRACT :
The effect of postharvest heat treatment, gibberellic acid (GA) or ethylene application on the decay of lemons was studied in relation to the presence of the preformed antifungal compound citral and antifungal activity in flavedo against Penicillium digitatum. Citral content decreased during storage in parallel with the decline of antifungal activity in flavedo and with the rise of fruit decay. Young mature green lemon (6 months after anthesis) demonstrating relatively high resistance against P. digitatum contained around 900 micro g citral/gfresh weight of flavedo at harvest whereas decay-susceptible old yellow fruit (11 months after anthesis) contained <500 micro g/g. Heat treatment (36 deg C for 3 d) inhibited the decline of citral content in the peel and drastically reduced the % decay. After 4 months of storage the flavedo of heat-treated fruit contained about twice as much citral as fruit that did not receive heat treatment. GA dip (500 p.p.m. for 2 minutes) also inhibited decay developmen
t of stored fruit and slowed down the decline of citral content and of the antifungal activity in the flavedo. Ethylene treatment (25 p.p.m. for 3 d at 25 deg ) markedly reduced the citral content and antifungal activity in the flavedo. It is concluded that the effect of heat treatment and plant growth regulators on postharvest citrus decay may be related to the modulation of endogenous disease resistance of fruit by influencing the changes of preformed antifungal materials such as citral.