Ultrastructure and Nitrogenase Activity of Frankia Grown in Pure Culture and in Actinorrhizae of Alnus, Colletia and Datisca Spp.

Abstract

Plant species, able to produce N2-fixing root nodules with actinomycete-like organisms have been discovered in about 200 species distributed over 21 plant genera. In order to distinguish these plants from the nodulated leguminous plants, the term “nodulated non-legumes” was used. Recently, Fessenden has proposed to change this name into “actinorhizal plants, i.e. plants bearing actinorhizas (Fessenden, 1979). The latter term was introduced in order to distinguish the root nodules induced by actinomycetes from those with Rhizobium as microsymbiont.