NITROGEN METABOLISM IN LICHENS. VII. NITROGENASE ACTIVITY AND HETEROCYST FREQUENCY IN LICHENS WITH BLUE-GREEN PHYCOBIONTS

摘要: The N2(C2H2) fixing activity was surveyed in lichens of diverse structure and habitat, all containing a blue-green phycobiont; twenty-six species from fourteen genera are reported for the first time to fix nitrogen. Rates fixation showed great variability between different lichen samples. proportion heterocysts, as assumed site N2 fixation, estimated above together with additional species. In one phycobiont, heterocysts form about 4% total algal cell population; those two phycobionts member is found special structures has very high typically 20-30%; appears reflect this. may be associated proximity green phycobiont.