Algae. 2000; 15(4): 183-193.

Mixed-Phase Reproduction in Antithamnion sparsum Tokida (Ceramiaceae, Rhodophyta) from Korea

Gwang Hoon Kim, In Kyu Lee

The life history of Antithamnion sparsum Tokida (Ceramiaceae, Rhodophyta) was investigated in four different populations of Korea. Mixed-phase reproduction and bisexuality were observed in haploid and diploid phases of field collected as well as cultured plants. The spores from haploid male/tetrasporangial plants exhibited two kinds of sex differentiation; becoming all males or male and female plants showing 1:1 sex ratio. The haploid gametophytic plants showed male : female = 1:1 sex ratio independent of environmental factors. The occurrence of mixed-phase plants, however, was different depending on environmental factors and developmental stage of each plant. In diploid plants, the sexual reproductive structures occurred temporarily at early stage of spore germination. In haploid plants, however, it occurred consistently at mature male plants. Ploidy of nuclear phase of each isolate was examined by video interfaced image processor.