SOLUBLE PHENOLIC-ACIDS IN CAPSICUM-ANNUUM STEMS INFECTED WITH PHYTOPHTHORA-CAPSICI

The soluble phenolic acids of the stems of three Capsicum annuum culti vars associated with differing resistance to Phytophthora capsici show ed qualitative and quantitative variation after inoculation, notably a n increase in the total phenolic acid content in the resistant and int ermediate varieties. The soluble phenolic acids also retarded mycelial growth of P. capsici in culture. The most pronounced inhibitory effec t was produced by t-cinnamic acid, followed by p-hydroxybenzoic, vanil lic and salicylic acids. Colonization and necrosis spread throughout t he stem of the susceptible cultivar whereas the stem of the resistant cultivar was only partially invaded. In the latter, invasion of the ti ssue adjacent to necrosis occurred in only 20% of the plants.