Survival and growth of alpha-spores of Porphyra schizophylla Hollenberg (Rhodophyta: Bangiophyceae)

Alpha-spores of the intertidal Porphyra schizophylla Hollenberg f. norrisii Mumford appear able to tolerate environmental stress factors associated with intertidal habitats, (viz., drying of water films with salt crystal formation, increased salt concentrations in the surrounding water, exposure to humid air when spores are enclosed in water films), and to produce Conchocelis filaments of normal appearance when subsequently germinated in sea water cultures. Tolerances of lowered salinities were observed down to 17.4%., but little survival at salinities lower than this. Alpha-spore germination on thalli of intertidal macro-algae was observed, with initial penetration in some cases. Penetrations of algal thalli were observed with Conchocelis filaments of α-spores germinated on red algae from low intertidal and subtidal habitats. Cell recognition phenomena would seem to be involved in these growth responses.