Nitrogen-fixing nodules on roots of the garden pea Pisum sativum. The picture shows the roots of a pea plant with clumps of nodules that are attached to side roots. The pink tinge visible on some of the nodules is due to the presence of leghaemoglobin, a protein involved in the process of nitrogen fixation. Nodules of this type are produced when roots are infected by the soil bacterium Rhizobium leguminosarum. The relationship is one of symbiosis; the bacterium benefits from an amenable environment within the plant, and the plant benefits from the bacterial ability to fix atmospheric nitrogen within the nodules. Biological nitrogen fixation by Rhizobium and other organisms is the major source of nitrogen for agricultural crops globally, and avoids the waste and environmental water pollution often associated with the use of chemical fertilisers. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Burgess, Dr. Jeremy |
Bildgröße: | 5212 px × 3468 px |
Modell-Rechte: | nicht erforderlich |
Restrictions: | - |