Sinorhizobium medicae is one of many species of nitrogen fixing bacteria. They are able to take nitrogen from the air and combine "fix" it with other elements to make nitrogen compounds (fertilizer). This makes the nitrogen available for plants and other organisms (like us). Many legumes (plants of the pea family, Fabaceae ) associate with nitrogen fixing bacteria. That is why some of these plants are used in crop rotation.
This "weed" is burclover, Medicago polymorpha. In its roots it provides an environment favorable to the nitrogen fixing bacterium, Sinorhizobium medicae .
Here we can see the
little lumps on the roots of the burclover. Each
colony of bacteria, Sinorhizobium medicae.
shows the details
of root nodules.
[ Classification, Taxonomy
[Monera ] [Backyard Biology ] [ Science Can Be Fun ]