PERITHECIAL FORMATION IN GELASINOSPORA RETICULISPORA. I. EFFECTS OF LIGHT AT TWO DIFFERENT GROWTH STATES

Hyphae of Gelasinospora reticulispora were cultured on corn meal agar in a growth tube at 25 ± 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^?1), 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 age-dependent, 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.