THE RELATION OF GROWTH REGULATORS TO THE DEVELOPMENT OF SYMPTOMS AND THE EXPRESSION OF STEM RESISTANCE IN WHITE PINE INFECTED WITH BLISTER RUST

Abstract

The application of the growth regulators indoleacetic acid and gibberellic acid to stems of white pine seedlings produced many symptoms characteristic of the disease caused by the blister rust fungus, thus suggesting their possible involvement in gall formation. When a kinin-like compound, benzimidazole, was applied, a wound periderm was initiated in seedlings infected with the blister rust fungus but not in healthy seedlings. This effect was augmented by indoleacetic acid and gibberellic acid. It seems to be a phenomenon very similar to that observed in stem-resistant white pine, and a possible relationship is proposed based on anatomical studies.