EFFECTS OF NITRATE CONCENTRATION ON THE GROWTH AND PHYSIOLOGY OF LAMINARIA SACCHARINA (PHAEOPHYTA) IN CULTURE

Abstract

Laminaria saccharina Lamour. sporophytes were grown in enriched and synthetic media through a range of nitrate concentrations, There was an approximately linear relationship between growth and nutrient concentration up to 10 μ substrate concentration. The half‐saturation constant (K2) was ca. 1.4 μ NO3‐. The internal levels of NO3‐ increased at substrate concentrations above 10 μM b>3‐ and reached levels several thousand times higher than the surrounding medium. Thus there is evidence for luxury consumption of NOsb>3‐. The chlorophyll content and photosynthetic capacities of plants also increased with increasing external NO3‐ The ecological implications of this work are considered. Copyright © 1978, Wiley Blackwell. All rights reserved