ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Effects of hypoxia on the senescence of horticultural crops.

Solomos, T.;

Postharvest Horticulture Series - Department of Pomology, University of California Year: 1997 Issue: No. 18 Pages: 138-148 Ref: 22 ref.

1997

บทคัดย่อ

The concentrations of O2 that may initiate the beneficial effects of hypoxia on the storage life of horticultural crops and the possible mechanism(s) involved in these processes are reviewed. The experimental data indicate that the decrease in respiration caused by hypoxia cannot be attributed to the restriction of mitochondrial terminal oxidases but rather to the restriction of the early steps of glucose oxidation. The retarding effects of hypoxia on the onset of the climacteric rise in C2H4 evolution are saturable in that for O2 to inhibit the onset of senescence, its concentration must be decreased below a certain level. In the case of apples, O2 concentrations larger than 6% fail to retard the rise in C2H4 evolution, indicating that there may be a sensor of O2 concentration. O2 concentrations that retard senescence have been observed to induce anoxic proteins. The decrease in the rate of ripening by low O2 is also saturable. In avocado fruits, concentrations above 5.5% O2 do not inhibit the

synthesis of proteins associated with normal ripening. The timing of the application of low O2 is also crucial for its ability to retard senescence. In Gala apples, the application of 1.5% O2 immediately after harvest suppresses the accumulation of ACC oxidase protein, and C2H4 evolution, for periods of up to 200 days, whereas when it is applied after the onset of the increase in C2H4 evolution, its effectiveness is decreased appreciably. A similar effect is also observed in the efficacy of 1.5% O2 in reducing scald development in Granny Smith apples.