BOUNDARY-ZONE FORMATION IN PEACH BARK IN RESPONSE TO WOUNDS AND CYTOSPORA-LEUCOSTOMA INFECTION

Seedlings of peach Prunus persica (L.) Batsch cv. Halford were mechanically wounded, or inoculated with mycelium of C. leucostoma (Pers.) Fr. Bark samples for histological study were taken from margins of visibly affected areas at varying times after treatment. Most response to wounding and pathogen colonization were basically similar differing only in timing and extent of response examined. Nonspecified host responses included gum production, changes in cell wall polysaccharides, cell wall lignification, and formation of suberized impervious tissues as part of the process of necrophylactic periderm formation. The presence of the fungus was associated with inhibited differentiation of living tissues, and, as a result, host processes responsible for impervious tissues and necrophylactic periderm formation were affected adversely.