Nodules of the nitrogen-fixing bacteria Rhizobium leguminosarum on the roots of a Medicago sp. plant. Medicago is a legume, a family of plants that are unable to make use of atmospheric nitrogen. Instead, bacteria such as R. leguminosarum grow in the roots of the plant and convert atmospheric nitrogen into organic nitrogen compounds that the plant can use. This is a symbiotic relationship, with the bacteria receiving carbohydrates for use as an energy source in return. Magnification: x14 when printed 10 centimetres wide.
Model release not required. Property release not required.