On the Inhibitory Effect Induced by Tobacco Mosaic Virus in Phaseolus vulgaris Plants

ABSTRACT An increase in the inhibitory effect against infection by TMV was found in the juices extracted from the primary leaves of French beans previously inoculated with active TMV or ultraviolet‐inactivated TMV as compared with that of the control leaves. No difference in the induced inhibitory effect was observed between active and ultraviolet‐inactivated preparations of the necrotic and ordinary strain of TMV, however, the interfering activity of active TMV was greater than that of ultraviolet‐inactivated TMV when boh strains were inoculated simultaneously on the leaves of French beans. These phenomena were not produced by TMV inactivated by heating at 100 C for 10 min. Further, it was ascertained that there was an increase in the inhibitory effect found in the juices from the uninoculated apical or basal parts and petioles of inoculated leaves when the other parts of the leaves were inoculated previously with TMV. Similarly, the induced inhibitory effect was found in the plumules produced at the base of the TMV‐inoculated leaves.