Correlation between Nodule Ultrastructure and Ability to Produce Stem Nodules in Aeschynomene spp.

抄録

Certain features of bacteroid ultrastructure in root nodules of Aeschynomene spp. cor-relate with the ability of the plant to produce stem nodules. Bacteroids of root nodules of stem-nodulationg species are relatively complex structurally and contain extensive invaginations of the membranes, clusters of DNA organized into nucleoids, and several electron opaque inclusions. The bacteroids in all of the stem-nodulating Aeschynomene species examined are generally enclosed singly in peribacteroid membranes and are oval-shaped. The bacteroids of non-stem nodulating species are varied in morphology (pleomorphic, rods and near ovals) and contain much less extensive invaginations of the membranes than the stem nodulating species. Some characteristics, such as the absence of interstitial cells and lack of infection threads, are found throughout the Aeschynomene root nodules examined. These data indicate that bacteroid ultrastructure might seve as structural clue as to potential stem-nodulating species and may relate to an underlying metabolic difference between stem-nodulating and non-stemnodulating spp.