Perithecial Formation in Gelasinospora Reticulispora. I. Effects of Light at Two Different Growth States

Abstract

Hyphae of Geiasinospora reiicutispora were cultured on corn meal agar m a growth tube at 25 k 0.4"C under different light conditions. While the hyphal tip was growing, perithecia were not formed under continuous white light (ca. 2000 ergs cm-2 sec-'), but some perithecia were initiated in total darkness. However, when white light was given after a dark period, perithecial formation was greatly promoted. In these cases, perithecial formation occurred in older portion of the culture (the portion nearest the point of inoculation) at first, and then gradually spread to the younger portion. Immediately after the tip of hyphae reached the other end of the growth tube, perithecia were induced in the youngest portion of the hyphae irrespective of the photoconditions; then formation proceeded toward the older portion. This induction was not agedependent, because in growth tubes with different lengths, perithecia always became visible ca. 24 hr after the tip of hyphae reached the other end of growth tube. The photoinhibitory effect was no longer observed thereafter, but photopromotive effect was still evident.

Development of the fruit bodies of Gyromitra esculenta

“…Apparently, a minute quantity of light in March (one lux or less) is sufficient to induce formation of tiny fruit bodies in G. esculenta (see Inoue & Furuya 1970). The discovery of a mycochrome in this species might make it possible to develop techniques· for the cultivation of the fungus.…”

Developmental Anatomy of Experimentally Induced Ascocarps in Gelasinospora reticulispora

“…Ascocarps formed under this condition, therefore, should be called perithecia. Ascocarps induced by aging under continuous white light : Although it was reported that no visible ascocarp occurred in cultures placed under continuous white light for 7 days (Inoue and Furuya, 1970), ascocarps were formed in the cultures even under continuous white light when incubated for a longer period of time. Ascocarp development took place very similarly to that just described, except for about 2 days of retardation, counted from the inoculation.…”

“…84 a single ascospore. Culture procedures and light sources were previously described (Inoue and Furuya, 1970). Samples were obtained as an agar block (about 1 cm long x 1 cm in width x 3 mm in depth) from the region of the growth tube where the earliest ascocarps had appeared.…”

“…Recently, Inoue and Furuya (1970) reported that ascocarps were synchronously induced in a homothallic fungus, Gelasinospora reticulispora (Sordariaceae) when the tip of the hyphae incubated in a growth tube reached the distal end of the tube, or when a white light exposure was given after a period of dark incubation while the hyphal tip was growing. They reported also that ascocarps were gradually produced due to aging of the culture.…”