A Life History and Hybridization of Antithamnion sparsum Tokida (Rhodophyta, Ceramiaceae) in Culture

홍조 Antithamnion sparsum Tokida의 생활사 및 교배에 관한 연구

Antithamnion sparsum Tokida isolated from the southern and western coasts of Korea was investigated in culture, comparing the morphological character with A. defectum Kylin from the Pacific North America. A. sparsum basically showed a Polysiphonia-type life history. However, it sometimes exhibited a monoecious reproducton and the carpospores released from the cystocarp by self-fertilization unexpectedly developed into the plants bearing spermatangia alone. These male plants were not functional up to 60 days culture. The results of intraspecific crosses between populations of A. sparsum were positive and the hybrid carpospores gave rise to normal tetrasporophytes. On the other hand, theinterspecific crosses between A. sparsum and A. defectum were successful partly, evidenced by the gonimoblast development and the release of carpospores in case of A. sparsum (male)$\times$A. defectum (female), but not in case of A. sparsum (female)$\times$A. defectum (male). Thus, the both species were still under the speciation.