Effects of nitrogen supply and continuous darkness on growth and photosynthesis of the arctic kelp Laminaria solidungula

摘要

Sporophytes of the arctic kelp Laminaria solidumgula were collected from the Beaufort Sea and kept for 7 months at 0±1.5 deg.C in a factorial experiment under two light (contrinuous darkness or 25 μmol photons m~2 s~1 on a 12: 12 L/D cycle) and two nutrient regimes (with or without added nitrate). We monitored growth rate and at the end of the experiment measured the following on both new and old blades: carbon and nitrogen content, chlorophyll and carotenoids, photosynthetic light-response (p vs. I) curves, and photosynthetic unit size (Chl/P_700).