Some plant hemoglobins help to fix nitrogen, according to researchers at the Max Planck Institute. This hemoglobin acts as the hemoglobin of mammals, since it participates in some way in the transport of oxygen.
For research the legume Lotus japonica has been used. In the nodules of the roots of this plant is abundant hemoglobin, as shown in the red color, which keeps the oxygen concentration low. This is fundamental for the fixing of nitrogen, since otherwise the work of the nitrogase enzyme would be difficult.
Plants fix nitrogen to grow. In the nodules of the roots of the legumes, for example, it is fixed symbiotically, assisted by a bacterium. Thanks to its enzymes, such as nitrogase, the plant receives nitrogen converted into ammonia.