title: Ultrastructure of the Alnus crispa var. mollis Fern. root nodule endophyte.
abstract: Nitrogen-fixing, field-obtained root nodules of the silky green alder were studied by transmission electron microscopy.  The nodule endophyte exhibited a prokaryotic cytology and was present in two forms: the hypha(0.3-1.0mum), which was branched and septate, and the vesicle (3-5mum), which was also septate and developed at the parental hypha tip.  Bacteria-like cells, previously observed in light microscopy studies, were not seen in the present work.  The actinomycete-like endophyte penetrated through the host cell wall and becane enveloped by a capsular material (0.1mum), the whole being enclosed by host membranes.  In some host cells, the endophyte appeared to lyse and become a mass of shrunken debris.  The fine structure of the Alnus crispa var. mollis root nodule endophyte was found to be similar to that of other nonleguminous root nodule endophytes.
mesh_terms: D001419:Bacteria / Q000378:metabolism / Q000648:ultrastructure*; D002473:Cell Wall / Q000648:ultrastructure; D003461:Crystallography; D003593:Cytoplasm / Q000648:ultrastructure; D002479:Inclusion Bodies / Q000648:ultrastructure; D008854:Microscopy, Electron; D009586:Nitrogen Fixation; D009940:Organoids / Q000648:ultrastructure; D010944:Plants / Q000382:microbiology* / Q000648:ultrastructure; D012988:Soil Microbiology; D013559:Symbiosis; D014197:Trees