Red light inhibition of spore germination in Ophioglossum crotalophoroides

Abstract

Spores of Ophioglossum crotalophoroides Walt., which give rise to subterranean, nonphotosynthetic, mycorrhizal gametophytes, germinate in the dark and not in the light. Red light, like white light, prevents the germination of these spores. Germination occurs after exposure to far-red. The effects of far-red light can be reversed by red light and those of red light can be partly reversed by far-red light, confirming the involvement of phytochrome. With the spores of O. crotalophoroides, the active form of phytochrome, Pfr, prohibits germination. The photoinhibition of germination by white or red light insures that these spores germinate underground in nature. Hypogean germination improves the chances for adequate soil moisture and for the young gametophytes to be colonized by mycorrhizal fungi.