In situ measurements of uptake of inorganic carbon and nitrogen by the aquatic liverworts Jungermannia vulcanicola Steph. and Scapania undulata (L.) Dum. in an acid stream,Kashiranashigawa, Japan

In situ uptake of inorganic carbon and nitrogen by the aquatic liverworts Jungermannia vulcanicola Steph. and Scapania undulata (L.) Dum. was measured in an acid stream, Kashiranashigawa, Japan. The uptake activities were similar in the both species. The activities were highest at the tip of shoots, and decreased gradually towards the base. Carbon uptake at the tip in the light was 10.4 × 10^–4 for J. vulcanicola and 8.1 × 10^–4 g C g dry wt^–1 h^–1 1 for S. undulata. Ammonium was effectively incorporated into the shoots, and the uptake activity at the tip was between 1.9 × 10^–5 and 5.8 × 10^–5 g N g dry wt^–1 h^–1. Nitrate uptake was smaller than ammonium uptake. The ratio of dark to light uptake in ammonium uptake experiments was larger than that in carbon uptake experiments. These results suggest that the liverworts use ammonium as a major nitrogen source, and that ammonium uptake was less dependent on light than carbon uptake.