A REPORT ON THE CULTURE OF SOME SPECIES OF HALOSACCION, RHODYMENIA AND FAUCHEA

SPARLING, SHIRLEY R. (U. California, Santa Barbara, Goleta.) A report on the culture of some species of Halosaccion, Rhodymenia, and Fauchea. Amer. Jour. Bot. 48(6): 493-499. Illus. 1961. -Cultures of the red algae, Halosaccion glandiforme (Gmelin) Ruprecht, Rhodymenia palmata f. mollis Setchell et Gardner, Fauchea laciniata J. G. Agardh, and F. fryeana Setchell were started from spores and in some instances maintained for about 21/2 yr. Culture methods are described and the plants obtained in culture compared to those in nature. Of the plants cultured, only some of F. laciniata became fertile. The use of spores undergoing their first division in germination for observation of mitotic divisions is reported. THE existence of plants of Halosaccion glandiforme (Gmelin) Ruprecht and Rhodymenia palmata f. mollis Setchell et Gardner with carpogonia and carpospores never has been shown. In an endeavor to obtain more information concerning the life cycles of these 2 representatives of the Rhodymeniaceae, cultural studies were undertaken. For comparative purposes, cultures of Fauchea laciniata J. G. Agardh and F. fryeanra Setchell were also started, even though the life cycles of these algae probably can be inferred, from the fertile plants which occur in nature, to be similar to that of the majority of the Florideophycidae. Several persons (Killian, 1914; Dammann, 1930; Chemin, 1937; Kylin, 1956 [for a list of references]) have cultured members of the red algae and described early stages of development. However, there have been few reports of any larger, non-filamentous red algae becoming fertile in culture, and usually the cultures were maintained for only a few weeks. Dammann (1930) obtained tetraspores on plants cultured from carpospores of Halarachnion ligulatuim (Woodward) Kiitzing, a member of the Gigartinales in which tetraspores had teen unknown previously, but the tetrasporophytes, unlike the gametophytes of this species, proved to be small, microscopic plants. Yabu (1958) maintained cultures started from carpospores of Grateloupia turuturu Yamada for several months, but none of the germlings reached a stage which resembled the mature plants. CULTURE METHODS-Cultures of Halosaccion glandiforme were started in the summer of 1957 and those of Rhodymenia palmata f. mollis, Fauchea laciniata and F. fryeana in the summer of 1958. Some of the cultures of Halosaccion and Rhodymenia were maintained until May, 1960. The plants used in establishing cultures were 1Received for publication January 1, 1961. The author wishes to acknowledge the support through grants of the National Science Foundation and the President's Committee on Research of the University of British Columbia. collected on or near San Juan Island, Washington. Halosaccion glandiforme and Rhodymenia palmata f. mollis were collected intertidally or subtidally, and Fauchea laciniata and F. fryearu were obtained by dredging. Cultures were started at the Friday Harbor Laboratories of the University of Washing. ton on San Juan Island, and were transferred at the end of the summers to the University of British Columbia and then in the fall of 1959, to the University of California, Santa Barbara. Cultures were initiated by placing a piece of the fertile thallus, which had been wiped as free as possible of contaminants and rinsed well in filtered sea water, into a container with filtered sea water and leaving it overnight. Mature spores, when present, were released in large numbers by the next morning when the thallus was removed. Upon being released, the spores settled to the bottom and the young germlings attached themselves firmly to the substrate. The cultures were started in small Stender dishes (50 ml) or in clear plastic dishes (400 ml) with cover glasses on the bottom. As the plants grew and it became desirable to increase the amount of the culture medium, the cover glasses with the attached plants or the entire Stender dishes were placed in larger plastic containers. The culture containers were covered and no means was provided for mechanical agitation of the medium. Except at the Friday Harbor Laboratories, where untreated sea water was used for the cultures, the plants were grown in autoclaved Erd. shreiber's solution (F0yn, 1934). Usually the medium in the smaller dishes was changed every week; in larger dishes it was changed at least every 2 weeks. It is evident that with this method of starting cultures, they were not unialgal, and one of the biggest difficulties was to control the growth of other algae such as diatoms, Ectocarpus and Cyanophyta. However, no contaminants which could be confused with the red algae being studied were present. Since the germlings of the red algae attached themselves rather securely, the growth of