Jump to content


From Simple English Wikipedia, the free encyclopedia
Rhizobia bacteria in nodules fix nitrogen
Soybean root nodules, each containing billions of Bradyrhizobium bacteria

Rhizobia are Gram-negative soil bacteria which grow inside the root nodules of legumes (the pea family: Fabaceae).

The growth of this bacteria is beneficial to their plant host. They fix (absorb and chemically change) nitrogen from the air and convert it into the chemical ammonia (through the help of enzymes). The host plant breaks down this ammonia and uses it for growth.

In return, the plants provide the bacteria with nutrients for growth from products of plant photosynthesis.[1]

Rhizobia require a plant host; they cannot independently fix nitrogen. As this relationship is beneficial for both plant and bacteria involved, it is a classic example of symbiosis and mutualism[2] which are found in all Rhizobia.

Rhizobia is very important in aiding plant growth in soils with low Nitrogen concentrations and is classed as a fertiliser for soil.[3]

History[change | change source]

Rhizobia was discovered by Martinus Willem Beijerinck in 1888.[4]

The word rhizobia comes from the Ancient Greek "ῥίζα" (rhiza) for root and "βίος" (bios) for life.

References[change | change source]

  1. "Welcome to Farming For a Better Climate - Farming For a Better Climate". www.farmingforabetterclimate.org. 2023-02-24. Retrieved 2023-07-01.
  2. Sawada, Hiroyuki; Kuykendall, L. David; Young, John M. (2003). "Changing concepts in the systematics of bacterial nitrogen-fixing legume symbionts". The Journal of General and Applied Microbiology. 49 (3): 155–179. doi:10.2323/jgam.49.155. ISSN 0022-1260. PMID 12949698.
  3. Jaiswal, Sanjay K.; Mohammed, Mustapha; Ibny, Fadimata Y. I.; Dakora, Felix D. (2021-01-27). "Rhizobia as a Source of Plant Growth-Promoting Molecules: Potential Applications and Possible Operational Mechanisms". Frontiers in Sustainable Food Systems. 4. doi:10.3389/fsufs.2020.619676. ISSN 2571-581X.
  4. Wilkinson, Lise (2001-05-30). "Beijerinck, Martinus Willem". eLS. doi:10.1038/npg.els.0002363. ISBN 978-0-470-01617-6.