| ISHS Acta Horticulturae 464: International Postharvest Science Conference Postharvest 96
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| Authors: | J. R. De Ell, Robert K. Prange, Dennis P. Murr |
| DOI: | 10.17660/ActaHortic.1998.464.16 |
| Abstract:
Chlorophyll fluorescence was evaluated as a rapid indicator of low O2 and high CO2 stress in stored apples. ‘McIntosh’ apples were harvested in September 1994 from Nova Scotia orchards, stored in controlled atmosphere (CA, 2.5% O2 and 4.5% CO2) at 3°C for ˜5 months and then subjected to low O2 treatments of 1%, 2%, 4% or 8% for 1, 2, 4, or 8 d at 20°C. Similarly, ‘Delicious’ and ‘Golden Delicious’ apples were harvested in October 1994, stored in CA at 0°C for ˜6 months and then subjected to high CO2 treatments of 5%, 10% or 20% for 1, 2, 4 or 8 d at 20°C. Chlorophyll fluorescence was measured by an OS-500 Modulated Fluorometer, using the Fv/Fm test (Method 1 on fluorometer) and the Fast Actinic test (Method 4 on fluorometer). Fv/Fm was found to decrease in apples stressed with either low O2 or high CO2, while T½ (half-time for rise in Fv) was found to increase in the stressed apples. The effects of low O2 or high CO2 on Fv/Fm and T½ were observed after 1 d, and this did not change with increased exposure time. Although ‘Delicious’ and ‘Golden Delicious’ apples differed in their relative fluorescence yields, both cultivars responded similarly to high CO2 stress. Our results indicate that chlorophyll fluorescence techniques can detect low O2 or high CO2 stress in apples prior to the development of associated disorders, and thus has potential as a rapid and non-destructive method to screen for atmospheric stress tolerance in apples. | |
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