ABA effects on ethylene production, PAL activity, anthocyanin and phenolic contents of strawberry fruit

Effects of exogenously applied abscisic acid (ABA) on ethyleneproduction rate, phenylalanine ammonia-lyase (PAL) enzyme activity, andanthocyanin and phenolic concentrations in harvested strawberry cv. Everestfruit were evaluated. Colouration and firmness were also assessed on fruit held for 3days at 20 °C. ABA treatment accelerated fruit colour andsoftening. Treatment with 10^–5 or 10^–4 mol ABAl^–1 stimulated ethylene production. Anthocyanin and phenoliccontents and PAL activity increased during storage, but more rapidly in ABAtreated fruit. As a result, red colour development was accelerated. EndogenousABA may play a role in strawberry fruit colour development during ripeningthrough up-regulation of ethylene production and PAL activity.