STUDIES ON WHITE PINE PHENOLS IN RELATION TO BLISTER RUST

Abstract

Healthy white pine leaf tissue and leaf tissue infected with the white pine blister rust fungus (Cronartium ribicola Fischer) were studied using histochemical methods to determine the location of phenolic substances in the host and to observe any changes in their distribution as a result of disease. All of the phenolic compounds detectable at the cellular level were observed in the vacuoles of the cells. After infection with the blister rust fungus, some of the phenols normally found in the vacuoles could be detected in the cytoplasm of the cells and on the cell walls. The release of the phenolic substances occurred in conjunction with fragmentation of the vacuoles, a phenomenon observed in infected first-season foliage but not in second-season foliage. The possibility that this could be associated with the known greater resistance of first year leaves when compared with second year leaves is discussed.