Definition of bacteroid in US English:



  • Of the nature of or resembling a bacterium.

    • ‘At that time, nodule plant fraction and bacteroid soluble protein contents did not show any significant effect by ABA, whilst the latter only declined by day 9.’
    • ‘Cytosolic PEP carboxylase in nodules catalyses the conversion of PEP and HCO - 3 (in equilibrium with CO 2) into oxaloacetate, which is used for the bacteroid respiration during nitrogen fixation.’


  • A bacteroid organism or structure, especially a modified cell formed by a symbiotic bacterium in a root nodule of a leguminous plant.

    • ‘The soluble protein content determined after pelleting of bacteroids and cell debris of these nodules had dropped to nearly 25% of the soluble protein content of nodules from flowering, non-senescent plants.’
    • ‘One mechanism that may increase benefits to relatives is found in strains whose bacteroids convert plant metabolites to rhizopines-compounds that cannot be re-assimilated by the plant nor used by unrelated soil bacteria.’
    • ‘Nodule cortex cells that contain ineffective bacteroids might undergo programmed cell death, although we are unaware of any evidence suggesting that such mechanisms exist.’
    • ‘Ammonia is exported from the bacteroids into the plant cell cytosol where it is assimilated, and directed to the synthesis of amino acids and/or ureides for subsequent export from the nodule.’
    • ‘These have to pass several cell layers to reach cells infected with Rhizobium bacteroids.’
    • ‘Nodulated plants utilize both combined nitrogen absorbed by the roots and nitrogen fixed by the bacteroids in the root nodules.’