K. Nimura, H. Mizuta, H. Yamamoto
Critical Contents of Nitrogen and Phosphorus for Sorus Formation in Four Laminaria Species
The critical contents of nitrogen and phosphorus for sorus formation in Laminaria angustata, L. japonica, L. ochotensis and L. religiosa were measured using cultured discs cut from the sporophytes. In L. japonica, fertile sporophytes were also used. Discs were cultured in Provasoli's enriched seawater or nutrient-poor seawater at 10 °C under 100 ?mol photons m?2 s?1 of irradiance (12L:1?2?D?). Regardless of the nutrient conditions in the culturemedia, the contents of nitrogen and phosphorus in the sorus part of discs and sporophytes of L. japonica were above 1.78 mgN cm?3 and 0.19 mgP cm?3 respectively, showing these values are critical for sorus formation in this species. Discs of L. angustata, L. ochotensis and L. religiosa in PES had higher contents of nitrogen and phosphorus in sorus parts than in L. japonica. The sorus area increased with accumulation of nitrogen or phosphorus in all species, but in L. angustata it was small despite the high contents of nitrogen and phosphorus, showing that this alga has a high nutritional cost in reproduction that might be a physiological adaptation to cold and nutrient-rich habitats.
Botanica Marina, Walter de Gruyter
Print ISSN: 0006-8055
Volume: 45, 04/2002
Pages: 184 - 188
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