Development of Bacteroids in Alfalfa (Medicago sativa) Nodules

Publisher Website
Google Scholar
Abstract
The morphology, acetylene reduction capability and nucleic acid content of bacteroids [Rhizobium meliloti] in different regions of alfalfa (M. sativa cv. Buffalo) nodules were studied by EM, gas chromatography and laser flow microfluorometry, respectively. Bacteroids in the nodule tips were small (1-2.5 .mu.M in length), had low nucleic acid content and contained distinct central nucleoids. These bacteroids were comparatively inactive in acetylene reduction in situ. Bacteroids in the middle regions of alfalfa nodules were greatly enlarged (5-7 .mu.m in length), had relatively high nucleic acid content, and did not possess central nucleoids. The bacteroids were very active in acetylene reduction. Bacteroids in the basal nodule region also were enlarged and without distinct nucleoid regions, but had relatively low nucleic acid content and low in situ acetylene-reducing activity.