Categories of gifted species, Biology

Categories of Gifted Species

This group of nitrogen fixers has been divided into three categories:

  1. Rhizobium which includes fast growing species,
  2. Bradyrhizobium which include slow growing strains and
  3. Azorhizobium which is a combination of traits from Rhizobium and Bradyrhizobium. Rhizobium is highly specific with respect to its host and that is why the nomenclature is based on the specific host which it infects.

For example the Rhizobium infecting clovers and peas are called trifolii and leguminosarum respectively. The genus Bradyrhizobium is not so rigid with regard to the host partners. All the strains of Rhizobium and Bradyrhizobium produce nodules on the host, but Azorhizobium produces nodules on the stem of Sesbania rostrata and Aeschynomene afraspera.

Parasponia is the only non-legume genus where the bacterial partner is Rhizobium. This observation has raised the hope of creating nitrogen fixing associations between Rhizobium and important crops like cereals. Nitrogen fixing nodules on the roots of woody plants like Alnus, Casuarino, Myria are formed by symbiotic association with Frankia a member of actinomycetes. Anabaena-Azolla association is experimentally shown to be a strong source of nitrogen fertiliser in wetland rice agriculture. Free-living heterocysts cyanobacteria are also known to contribute significant amount of nitrogen to the wetland rice ecosystem. Lichens are associations between fungi and N2-fixing cyanobacteria. They are very important source of N2 in barren harsh also known to occur in tropical plants like Psychotria partner.

Posted Date: 1/17/2013 4:55:32 AM | Location : United States







Related Discussions:- Categories of gifted species, Assignment Help, Ask Question on Categories of gifted species, Get Answer, Expert's Help, Categories of gifted species Discussions

Write discussion on Categories of gifted species
Your posts are moderated
Related Questions
In phylum colenterata if tissues are present in the body of an organism then why organs are not present as group of tissues makes an organuestion..

Q. What is R - Wave Amplitude? The R-wave amplitude in the lateral precordial leads usually decreases more in normal than in abnormal subjects and correlates with left ventr

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is meant by binomial nomenclature and what are its basic rules? Scientific nomenclature of a species must have, at least, two names: one that classifies it as genus and th

Quick transient responses - Behaviour of Plants Such responses are stimulated by factors showing significant variations over relatively small time period e.g., those showing w

Describe the Male Reproductive System? In addition to the primary sex organs, the testes, there are accessory structures that store, nourish, and activate the sperm, and conduc

Stem Cell Stem cell therapy could enable individuals to survive and contribute their alleles to the gene pool who might not have already done so thus increasing genetic diversi

Q. Why is the dietary obtainment of iodine so important for thyroid functioning? The obtainment of iodine from the diet is vital for the thyroid because this chemical element i

what is ontogeny recapitulates phyloeny

introduction in fungai