海藻胞子の發芽,生育に及ぼす光の影響に關する二,三の実験

Abstract

The spores of several algae (4 spp. in Chlorophyceae, 3 spp. in Phaeophyceae and 3 spp. in Rhodophyceae) were cultured in the laboratory under those different light-condions as follows: 1. Concerning to the light intensity; A) in full sunlight through a window glass, avoiding the direct rays, B) under a shade of one sheet of white cotton-cloth, C) under a shade of three thicknesses of white cotton cloth. 2. Concerning to the quality of light; under a colour filter using the solution of red, brown, yellow, green, blue, and violet colour pigments. 3. Concerning to the duration of light; A) long-day, 24 hours, B) normal-day, 10-12 hours, C) short-day, 8 hours. Results, shown in 1-5 tables, might be summarized as follows: a) When kept in darkness, the spores of green algae did never germinate nor grow into two-celled sporelings for more than 1.5 years, while most spores of brown-or red-algae did slowly germinate. In decreased light, the growth of sporelings of green algae were greatly retarded, while those of brown-or red-algae were rather accelerated. But one exception in green algae was observed, i.e. the sporelings of Monostroma grew more slowly in decreased light (B-condion) for about two weeks after germination, but there-after they set in faster growth then in full sunlight. b) The sporelings of green algae grew more rapidly under yellow, red, or blue light than under brown or green light. c) The spores of Enteromorpha germinated and developed more rapididly in the long-day condition. With Monostroma, however, the germination and development in the earlier stage were faster in the normal-day condittion, but after a while, more rapid growth and richer formation of spores were reversly found in the short-day condition.