PHOTOMORPHOGENESIS OF THE GAMETOPHYTES OF LYGODIUM JAPONICUM

Protonemata of Lygodium japonicum turn biplanar in both red and blue light regimes and remain filamentous in far‐red light. Biplanar gametophytes formed in red light are longer than broad with long, rectangular cells, whereas in blue light they appear broader than long with short, isodiametric cells. Transfer of protonemata of all ages from far‐red regime to red or blue light induces a morphological type of growth characteristic of the new light regime. However, only relatively young biplanar forms transferred from red or blue light are able to resume filamentous type of growth in a subsequent regime of far‐red light.