Effect of Light on Sporulation of Alternaria kikuchiana TANAKA

Effect of the continuous light exposure with white fluorescent lamp on sporulation of Alternaria kikuchiana Tanaka depended more or less on the kinds of media. On V-8 juice medium, pear leaf juice medium and dry apricot-V-8 juice medium, the spore production of the fungus were increased by the light exposure. Stimulately or inhibitory effect of spore production of the fungus on the dry apricot juice medium, which produced the most abundant spores among the media in darkness, were not observed when exposed to continuous light by white fluorescent lamp. Effect of the light exposure on sporulation of the fungus depend also on temperature and the distance from lamp to mycellium. In high temperature and long distance from lamp to mycellium, spore production of the fungus were decreased and the good growth of airial mycellium. On the other hand, in low temperature and short distance from lamp, the spore production of the fungus were increased. The spore formation of the fungus stimulated with black light blue fluorescent lamp, pure blue fluorescent lamp and sterile lamp among the lampes, in low temperature and short distance from the lampes on the all media except dry apricot juice medium. The spore formation of the fungus stimulated when exposed to continuous light with the glass filters which transmitted mainly 340mμ and 365mμ light in low temperature and long or short distance from the lampes on dry apricot-V-8 juice medium. On the other hand, spore formation of the fungus inhibited by 400mμ-500mμ, especially 450mμ light.