n. pl. rhi·zo·bi·a (-bē-ə) Any of various aerobic bacteria of the genus Rhizobium that form root nodules in leguminous plants, such as clover and beans, where they establish a symbiotic relationship in which the bacteria obtain carbon and energy from the plant while supplying the plant with nitrogen by nitrogen fixation. [New Latin Rhizobium, genus name : RHIZO- + Greek bios, life; see gwei- in the Appendix of Indo-European roots.] |
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