VIEW ARTICLE

Physiology and Biochemistry

Influence of Calcium Nutrition on Susceptibility of Rose Flowers to Botrytis Blight. Hanne Volpin, Graduate student, Department of Plant Pathology, ARO, Volcani Center, Bet Dagan 50250, Israel, Present address: Department of Microbiology and Plant Pathology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel; Y. Elad, researcher, Department of Plant Pathology, ARO, Volcani Center, Bet Dagan 50250, Israel. Phytopathology 81:1390-1394. Accepted for publication 25 March 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-1390.

Cut rose flowers were incubated in solutions of CaCl₂ or CaSO₄ for 2 days and then incubated under gray mold-conducive conditions. Severity of gray mold symptoms was reduced 60% by the treatments. Results varied with calcium concentration (1–50 mM) and rose cultivar. Ca(NO₃)₂ was added to the nutrient solutions of rose plants grown in plots in commercial greenhouses. Other nutrients in the fertilizer solutions were constant in the different treatments. The calcium content of stems, leaves, and flowers was increased by calcium treatment in the greenhouse. Calcium at a concentration of 3.5 mM reduced the severity of postharvest Botrytis blight in naturally infected flowers by 55%, and by 30% when flowers were further inoculated before incubation under humidity conditions. Ethylene production in flowers with high calcium content was decreased by 50–95%. Increasing the potassium concentration in the fertilizer solution negated the ability of calcium to reduce Botrytis blight susceptibility of flowers, probably due to competition for cation uptake. Calcium presence in liquid medium decreased the ability of Botrytis cinerea to utilize pectate and to produce polygalacturonases by up to 100%.