Abstract
To detect the presence of antifungal activity in arboreal plant tissues, cortical disks of one- to two-years-old shoots of 22 species belonging to 11 families including mulberry were placed on potato-dextrose agar (PDA) media seeded respectively with 6 species of fungi and bacteria, and assayed at 25C for 1-2 days and inhibition zones to microbial growth were observed (direct method). The disks of 11 species including mulberry and persimmon showed inhibition zones, indicating antifungal activity against Bipolaris leersiae and Fusarium roseum. The cortical disks of mulberry shoots showed antifungal activity on neutralised PDA, while those of persimmon showed antifungal activity only on acidified PDA. The cortical disks of mulberry shoots treated at -20C for 60min or in hot water at 60C for 10min failed to display any antifungal activity. Pieces of various organs of mulberry plant, i.e., leaf, petiole, cortical tissues of shoot and root showed antifungal activity, but antifungal activity could not be detected in xylem tissues of either shoot or root by this method. On the other hand, the acetone extracts from all of these pieces assayed by the direct method showed antifungal activity against B. leersiae. Antifungal activity could not be found in browned cortical tissues infected with pathogens by using the direct method, whereas acetone extracts showed antifungal activity.
