The culture of bisporangial plants ofDermatolithon litorale(Suneson) hamel et lemoine (Rhodophyta, Corallinaceae)

Abstract

The crustose coralline alga D. litorale from the Swedish west coast was cultured from bispores, with small shells as substrate. After 20 mo. fertile crusts were obtained. Crusts (at 26 mo.) were fixed and thin sections studied. The conceptacles contained only bisporangia with uninucleate bispores, as in the initial material. No other reproductive organs are known in this species. A previous cytological study on material from the same population showed that the uninucleate bispores are formed apomeiotically. D. litorale has an apogamous and apomeiotic life history. Previous cytological studies on a 2nd species, D. corallinae demonstrated that this alga has 2 parallel life histories in northern waters: 1 is triphasic (Polysiphonia-type) with meiosis at the formation of tetraspores and binucleate bispores and the other is apomeiotic with uninucleate bispores. The occurrence of apomeiotic life histories in algae and angiosperms in cold climates is briefly discussed.