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
What is nucleus where it is found? Nucleus :  The nucleus is present only in eukaryotic cells. It is the control center and is generally found in the center of the cell. The

Determine Nutritional Requirements in Hot Environments? Hot environments may be of two types: dry hot, as in the case of deserts or hot and humid in tropical rain forests and c

What are the Advantages of Grains Diabetics should have more grains, beans and starchy vegetables every day. Whole-\ grain foods are nutritious and high in fiber, such as whol

Define the factors effect the Quantity of Human Milk? A large healthy baby who can vigorously suck will induce and obtain much more milk from its mother than a small, sickly or

What is the difference between an ecological niche and a habitat? An ecological place is a set of peculiar activities, resources and strategies that a species explores to repro

Explain Microtube and Hedstorm file removal technique A Hedstorm file was then passed down the length of the tube until it engaged itself tightly between the obstruction an

After ovulation:- (a) what structure replaces the Graafian follicle (b) what hormone does it produce?   (a) After ovulation, the follicle is replaced by the cor

Q. How do the Golgi apparatus act and the rough endoplasmic reticulum in the production and releasing of proteins? The rough endoplasmic reticulum has in its outer membrane man

Bond specificity Some  enzymes  act  on  a particular  bond  (glycosidic,  peptide,  ester  etc.). Examples:  pepsin,  trypsin,  chymotrypsin  etc. are  all  only  acting  on

Element Required By Higher Plants Table shows the list of sixteen elements that fulfil the criteria of essentiality stated above, their approximate adequate concentration and