RESISTANCE OF ANACARDIUM OCCIDENTALE TO DECAY FOLLOWING ULTRAVIOLET RADIATION

Abstract

Many host plants produce defense substances against fungal pathogens. These chemicals are at times induced in harvested crops by physical agents employed in plant disease control. The pseudoapple of whole, unripe cashew fruits inoculated with Gilbertellapersicaria were exposed to ultraviolet - B (UV-B) radiation, and when reduction in decay was noticed thereafter, the peels were investigated for antifungal substances. Ten major compounds were detected from the peels by GC-MS, three of which had been previously reported to exhibit antifungal activities. The three were 2, 4-Di-tert-butylphenol(24DTBP); (Z)-3-pentadec-8-en-1-yl) phenol and 2-Methyl-Z, Z-3, 13-octadecadienol. Some fractions of the peel extract also inhibited fungal spore germination in vitro revealing the mode of action of the compounds. The results suggest that unripe host cashew fruits actively contributed to decay suppression with antifungals production in addition to the disinfecting action of UV-B.