On the Phytoalexin production of the soybean pod in reaction to Fusarium sp., the causal fungus of pod blight

II. On the effect of conditions of the spore suspension of the causal fungus upon Phytoalexin production

Abstract

Phytoalexin (PA for short) production of the soybean pod in reaction to Fusarium sp., as affected by conditions of spore suspension, was studied. PA was produced remarkably when suspensions containing spores more than 40per one microscopic field at 150-fold magnification, were placed on the soybean pod, while not at all when suspension with 3∼6 spores per one microscopic field was used. Both spore suspension heated at 100°C for 10 minutes and supernatant of suspension suspended with macerated spores, failed to induce production of PA. The supernatant of spore suspension, incubated for 24 hours at 23°C, revealed to possess ability to induce PA production, but lost the ability when the supernatant was heated at 60°C for 10 minutes.