Hideyuki Nagao

pp. 601 - 606

Abstract

The effect of three aqueous solution of biotin, thiamine and calcium pantothenate, on the growth of Exobasidium
vexans was examined in vitro. The germination process of basidiospores of E. vexans differed from those of the other
Exobasidium species. Basidiospore germination commenced after 19.5 hr incubation and chlamydospore-like bodies were
formed after 96 hr of incubation. Addition of biotin, calcium pantothenate, and thiamine to Difco PDA and Czapek’s medium
did not affect the proportion of germinating basidiospores. The length of germ tubes was enhanced only by addition of
thiamine in the media. Larger size germ tubes (thick germ tubes) were occasionally observed among the ordinary hyphae.
Most germlings of basidiospores developed chlamydospore-like bodies or autolysed on the media. Thick germ tubes
frequently appeared on the calcium pantothenate amended media and developed into a colony when these hyphae were
transferred to new calcium pantothenate amended media. However, further transfer of colonies did not successfully bring a
new colony to grow on the calcium pantothenate amended media. Vitamin B5
, calcium pantothenate, was only partially effective in generating the thick germ tubes and to induce the initial colony formation, whereas amendment of biotin and thiamine
to the media did not induce visible colony growth.