Photoperiodic control of sorus formation in the brown alga Laminaria saccharina

Abstract

ABSTRACT: Adult sporophytes of Laminaria saccharina (L.) Lamour were collected near Helgoland. southern North Sea, and cultivated in an experimental tank system at each of 5 temperatures (range 2 to 20°C) in short-day (SD; 8:16), long-day (LD; 16:5), and night-break (NB; 8:a: 1 indicates hours of darkness). The seawater of the experimental tanks was mixed continuously Sori were formed in SD, but not in LD and NB. Optimal temperature range for sorus formation was 10 to 15'C In SD, a period of retarded blade growth preceded sorus formation. :n) regimes (bar