Ammonia‐assimilating enzymes in bryophytes

Ammonia can be incorporated into amino acids by reductive amination of oxoglutarate, or by the glutamate synthase cycle via glutamine. The majority of plants possess the enzymes necessary for the operation of both these pathways although nitrogen is thought to be assimilated via the glutamate synthase cycle in most cases. Measurements of glutamate dehydrogenase, glutamine synthetase, and glutamate synthase activities are presented from a selection of bryophytes. The genus Sphagnum was found to be unique in lacking measurable glutamate dehydrogenase activity. The relevance of this in the nitrogen‐poor acid bog is briefly considered.