Stockage de l'azote chez Laminaria digitata cultivée en eau de mer enrichie: L'effet du dosage et du temps d'incubation

The distribution of nitrogen within the different parts of the thallus of the brown alga Laminaria digitata (Huds.) Lamour is described for plants gathered along the coast at Quiberon, France. Laboratory experiments were conducted using soaking methods with various concentrations of nitrogen and different incubation time. Incubation time had a greater effect than the concentrations used. By and large, the nitrogen content was high and stable in the meristematic region. In a nitrogen—enriched medium, the capacity for accumulation in Laminaria digitata is nealy uniform throughout the frond (± 3.5 % of dry weight). Difference appears only when we consider the starting stage for there is a negative gradient of concentration from the meristematic to the distale zone.