How is Rhizobium inoculation done?
Inoculation is the process of introducing the appropriate Rhizobium bacteria to the soil in numbers sufficient to ensure successful nodulation. This is done by coating the seed with a liquid or peat-based powder inoculant, or by treating the soil with a granular or liquid inoculant.
Which process is conducted by Rhizobium bacteria?
The symbiotic nitrogen-fixing bacteria invade the root hairs of host plants, where they multiply and stimulate formation of root nodules, enlargements of plant cells and bacteria in intimate association. Within the nodules the bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development.
What is nodulation in plants?
Nodulation is a host-specific process with each rhizobium having a defined host-plant range (Table 10-1). Rhizobia, normally found in the soil, respond to the plant-root environment (rhizosphere) by increasing their population levels and attaching to the root surface.
What is Rhizobium inoculant?
INOCULANTS. Inoculants are commercially prepared Rhizobium bacteria. There are many different species of Rhizobium bacteria and of those species, there are many different strains. Much of these are found naturally in the soil in very small amounts.
Which type of bacteria is Rhizobium?
Rhizobium and Bradyrhizobium. Rhizobium and Bradyrhizobium (class of the Alphaproteobac- teria, order of the Rhizobiales) are Gram-negative nitrogen-fixing bacteria that occur either as free-living soil bacteria or in interaction with the roots of leguminous plants. Cohabitation leads to the development of root nodules …
How infection thread is formed?
Infection thread formation is most often initiated when rhizobia become trapped between two root hair cell walls. This usually occurs when a deformed root hair forms a sharp bend or curl, and bacteria bound to the root hair become trapped between appressed cell walls (26).
Which bacteria is present in root nodules of leguminous plant?
Legumes are able to form a symbiotic relationship with nitrogen-fixing soil bacteria called rhizobia. The result of this symbiosis is to form nodules on the plant root, within which the bacteria can convert atmospheric nitrogen into ammonia that can be used by the plant.
What is Rhizobium and why is it important?
Rhizobium is a bacterium found in soil that helps in fixing nitrogen in leguminous plants. It attaches to the roots of the leguminous plant and produces nodules. These nodules fix atmospheric nitrogen and convert it into ammonia that can be used by the plant for its growth and development.
Which is the best inoculant to use on Rhizobium?
Rhizobia are vulnerable to ultra violet rays, so inoculant should be stored away from sunlight. Heat and wind will also dry out and kill rhizobia. Soil tests can indicate potential problems. “Inorganic nitrogen — nitrate, for instance — can inhibit the nodulation, nitrogen fixation process.
How are Rhizobium bacteria used in pulse crops?
Rhizobium bacteria are not very mobile in the soil, and thus, the inoculant must come in contact with the developing seedling for infection of root hairs to occur. Specific pulse crops require specific Rhizobium species for nodulation.
How are the processes of infection and nodulation related?
The complex process by which plant roots are infected by rhizobia is known as infection. The complex process in which nodules are formed is known as nodulation. Although the processes have different names, they are very closely interrelated and in one sense might be considered simply two parts of one process.
How does the plant provide nitrogen to the rhizobia?
The plant also provides nutrients and water to the rhizobia in the nodules and, in return, the rhizobia provide fixed nitrogen to the plant. The amount of nitrogen fixed varies with the type of crop, crop health, the supply of nitrogen already available in the soil, and other environmental conditions.