Studies on Phytoalexins VIII. The Effect of Some Further Factors on the Formation, Stability, and Localization of Pisatin in Vivo

Abstract

In a study of the effect of some further biological, physical, and chemical factors on the formation of pisatin, the following points were demonstrated: (1) Pisatin formation following heat treatment (45[degree]C) or anaerobic storage was dependent on the duration of the exposure period. Delayed inoculation, following some treatments, resulted in an increased capacity of the host to form pisatin. Pisatin concentration and host susceptibility was inversely related. (2) Pisatin formation was stimulated by several saprophytic fungal species. (3) Detached pea pod tissues retained their capacity to form or release pisatin for 20 days following inoculation. (4) Pisatin was stable in the tissues of Pisum sativum and mycelium of Ascochyta pisi. (5) Pisatin was localized in inoculated tissues and did not diffuse to neighbouring healthy tissues. The formation of pisatin in relation to alterations in host metabolism is briefly discussed.