DEVELOPMENTAL AND CULTIVAR COMPARISONS OF LIPOXYGENASE/LYASE-DERIVED VOLATILE COMPOUNDS FROM STRAWBERRY FRUIT

Abstract

Volatile products of the lipoxygenase/lyase pathway have been implicated in plant pathogen resistance mechanisms. Volatile compounds produced by strawberry fruit were measured by capillary GC using a direct headspace sampling technique. No intact fruit, assayed at the green, white, and red-ripe stages, emitted detectable amounts of volatiles by this method. However, crushed or damaged fruit yielded a few volatiles in the 1 μg/L range. The major compounds detected were derived from the lipoxygenase/lyase pathway and had the correct retention times for hexanal, c-3-hexenal, and t-2-hexenal. Hexanal and t-2-hexenal were produced by crushed white and red-ripe fruit whereas crushed green fruit produced these compounds and c-3-hexenal. Crushed white fruit from four cultivars, selected for reported differences in Botrytis cinerea resistance, yielded approximately equal amounts of hexanal and t-2-hexenal. The results will be discussed with respect to the possible involvement of these volatile compounds in pathogen resistance of strawberry fruit.