Bacteroid distributions in alfalfa nodules upon dark-induced senescence and subsequent partial rejuvenation [Rhizobium meliloti, dinitrogen fixation, nucleic acid, flow-microfluorometry, induced senescence]
1981
Paau, A.S. (Wisconsin Univ., Madison (USA). Dept. of Bacteriology and Center for Studies of Nitrogen Fixation) | Cowles, J.R.
Photosynthate availability directly controls the maturation, senescence and distribution of bacteroids (inoculum Rhizobium meliloti 102 F28) in alfalfa (Medicago sativa L. cv. Buffalo) nodules. Mature, dinitrogen-fixing bacteroids were located principally in the middle section (region) of 6- to 8-week-old nodules in light-grown alfalfa plants. Upon dark treatment of the plants, bacteroids in the middle region of a nodule were induced to senescence while those in the tip region began to mature faster. Senescence and deterioration of bacteroids in the basal region of a nodule also were more advanced in the dark-treated plants. Sugar supplied exogenously during the dark period retarded the senescence process. Exposure of the dark-treated plants to light partially restored nitrogenase activity. The distribution of bacteroids in the rejuvenated nodules was similar to that of the light-grown plants
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