Porphyra yezoensis bei Helgoland - eine entwicklungsgeschichtliche Studie

Abstract

A Porphyropsis-like epiphytic specimen found in the harbour of Helgoland was grown in culture and proved to be identical with the Japanese Porphyra yezoensis. Life history studies on this economically important alga resulted in some interesting and hitherto unknown details. The variability of the adult frond is fundamentally determined by the pattern of spore germination. Settled on Chaetomorpha filaments, monospores elongate within 20 minutes; the epiphytic germlings are attached to the substrate by a typical basal cell and give rise exclusively to elongated fronds provided with a cuneate base. Unattached spores, however, germinate into buds with rhizoids; they develop into elongated elliptical to oval fronds provided with round or cordate bases. Only plants with male areas were observed in the cultures, but Conchocelis was abundantly produced from cells of aged thalli. Grown in mussel-shells, the filamentous phase liberated conchospores for a long time. © 1986 Biologische Anstalt Helgoland.