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Postharvest Pathology and Mycotoxins

Spore Germination and Mycelial Growth of Postharvest Pathogens under Hypobaric Pressure. A. Apelbaum, Agricultural Research Organization, Institute for Technology and Storage of Agricultural Products, Division of Fruit and Vegetable Storage, P.O.B. 6, Bet Dagan, 50200, Israel; R. Barkai-Golan, Agricultural Research Organization, Institute for Technology and Storage of Agricultural Products, Division of Fruit and Vegetable Storage, P.O.B. 6, Bet Dagan, 50200, Israel. Phytopathology 67:400-403. Accepted for publication 4 June 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-400.

The effect of hypobaric pressures used for storage of fruit and vegetables on common postharvest decay-causing pathogens was tested. Spore germination, mycelial growth, and sporulation of the tested fungi were inhibited under hypobaric pressure at 23 C. Inhibition increased with the decrease in pressure below 150 mm Hg. Mycelial growth of Penicillium digitatum, Alternaria alternata, Botrytis cinerea, and Diplodia natalensis after 5 days at 100, 50, and 25 mm Hg was inhibited by 5%-25%, 45%-80%, and 100%, respectively, and germination was retarded by 0, 40%-82%, and 100%. Delay in fungal sporulation was recorded under 50 and 25 mm Hg. Inhibition of Geotrichum candidum var. citri-aurantii was less pronounced under these conditions. Admitting O₂ to the cultures held at hypobaric pressure partially reversed the growth inhibition effect. In all cases, normal growth was resumed after cultures were transferred from hypobaric to atmospheric pressure. Growth inhibition in cultures held under 50 mm Hg at O₂ partial pressure of 0.008 atmospheres was more pronounced than that in cultures held at 760 mm Hg with the same O₂ tension. A possible mode of action of the hypobaric pressure on fungal growth is discussed.