Interaction of red and blue light on the development of the protonema and bud formation in Pohlia nutans

Abstract

Red light induces bud formation in Pohlia nutans, but it is not sufficient for their normal development. For their development into leafy shoots 11 hours red light followed by 6 hours blue in a 24-hour cycle seems to be the best. It produces results almost similar to that of white light of 17 hours duration. By changing the order in the sequence of the above treatment (namely, 6 hours blue light followed by 11 hours red light) many buds are inhibited. Blue light alone completely inhibits bud formation but supplemented with red light this inhibitory effect of blue light is counteracted and buds are formed, provided a minimum exposure of red light is maintained. Red light, like kinetin, counteracts inhibitory effects of coconut water on bud formation. The results obtained emphasize the similarity in action of red light and kinetin on bud formation. Blue light promotes a very good growth of the protonema and in any combination with red light has produced greater protonemal growth than red light alone of 17 hours duration.