OBSERVATION ON THE ECOLOGY AND REPRODUCTION OF FREE-LIVING CONCHOCELIS OF PORPHYRA TENERA

¹ Department of Fisheries, Faculty of Agriculture, Tohoku University, Sendai, Japan

1. Free-living Conchocelis colonies under long-day conditions produce several types of reproductive bodies from which new Conchocelis colonies originate, revealing a new part of the life-cycle.

2. Three reproductive structures were observed and described: (a) inflated spherical cells; (b) strawberry-like structures; (c) special "sporangia" (SI).

3. The inflated spherical cells discharge single spores which develop Conchocelis colonies.

4. The interior cells of the strawberry-like structures and unicellular spore-like bodies discharged by disintegration of the structure produce germ tubes, and grow into Conchocelis colonies.

5. These Conchocelis colonies produce monosporangia and liberate the monospores that germinate into normal leafy thalli under short-day conditions. The spherical cells and the strawberry-like structures were produced on Conchocelis branches at temperatures higher than 18° C. and under long-day conditions (subdued light).

6. The spores liberated from sporangia (SI) formed under long-day conditions develop into various piantlets: (a) Conchocelis-like plants, globular bodies and abnormal blades in long day (14 hours' illumination daily): (b) plantlets having short and root-like filaments, blade-like bodies and massive plantlets in short day (9 hours' illumination daily).