A NEW NITROGEN‐FIXING CYANOPHYTE‐HEPATIC ASSOCIATION: NOSTOC AND PORELLA

Abstract
Porella navicularis, a common leafy liverwort in western North America, was found to possess numerous epiphytic Nostoc colonies. Although the abundance of colonies was variable, the association was found consistently throughout a broad geographic range. Unlike cyanobacteria in other hepatic assocations, the Nostoc occurred as distinct colonies harbored in crevices and curled margins of leaves. Heterocyst frequency was 3–7%. Acetylene reduction activity was present in 85% of samples examined, with an average value of 53.5 nmol C2H4∙g dry wt‐1∙hr‐1 and a maximum of 316 nmol C2H4∙g dry wt‐1∙hr‐1. This suggests that bryophyte nitrogen‐fixing associations may be more important than previously realized.
Funding Information
  • National Science Foundation (PCM‐8118148)