Symbiotic nitrogen fixers - nutrient cycles, Biology

Symbiotic Nitrogen Fixers - Nutrient Cycles

Of the symbiotic nitrogen fixing bacteria, species of Rhizobium form root nodules in legumes and are the most studied nitrogen fixers and the best understood. Species of Rhizobium are most specific to particular species of legumes. The rhizobia penetrate the root hair and once inside the root, the bacteria rapidly multiply and form swollen, irregular - shaped bodies in roots of legumes. Some non-legume w6ody plants also have root nodules and fix nitrogen symbiotically.

The organisms that cause the formation of nodule and fixation of nitrogen are actinomycetes (a kind of primitive fungus). Some examples of non-legumes are species of Alnus, Elaeagnus Myrica, Araucaria, Ginkgo, and Casuarina. Unlike legumes, which are largely tropical in origin, these nitrogen fixers originate in the temperate zone. Nitrogen fixation by blue green algae or cyanobacteria may take place in free living forms or in symbiosis with fungi as in certain lichens, mosses ferns and at least one seed plant. The fronds of the small free floating aquatic fern Azolla contain small pores filled with symbiotic blue green algae Anabaena that actively fix nitrogen. For centuries this fern has played an important role in the rice fields of China. Before the rice fields are planted the water filled paddy fields are covered with the aquatic fern which fixes enough nitrogen for the crop as it matures. This practice permits rice to be grown without further addition of nitrogen fertilisers. Symbiotic nitrogen fixers are more efficient than free living ones.

Posted Date: 1/19/2013 2:12:01 AM | Location : United States

Related Discussions:- Symbiotic nitrogen fixers - nutrient cycles, Assignment Help, Ask Question on Symbiotic nitrogen fixers - nutrient cycles, Get Answer, Expert's Help, Symbiotic nitrogen fixers - nutrient cycles Discussions

Write discussion on Symbiotic nitrogen fixers - nutrient cycles
Your posts are moderated
Related Questions
Which is the extraembryonic membrane whose function is to store nitrogen wastes of the embryo? Is this function present in placental mammalian embryos? The allantois is the ext

Q. What is the gross primary production of an ecosystem? How does GPP relate to photosynthesis? The Gross primary production of a GPP or ecosystem is the quantity of organic ma

In the prokaryotes,  RNA transcribed  from protein-coding  genes or messenger  RNA, mRNA,  need  little  or  no  changes  prior  to  translation.  In reality, several mRNA   molecu

Q. Dietary tips for hyperlipideinic patients? It is important to note here that the dietary modifications need to be individual in each patient and these should be tailored lo

How is excretion done in fishes? Fishes have a pair of kidneys that filtrate the blood. Bony fishes excrete nitrogen as ammonia, NH 3 , (they are ammoniotelic) and cartilagino

When lipid is added to a solution of a detergent in water, the detergent breaks up large globules of the lipid into much smaller globules. What effect do you think a detergent woul

Define Carbohydrate Metabolism of manganese? Mn is required for carbohydrate metabolism. Enzymes pyruvate carboxylase and phosphoenol pyruvate carboxy kinase involved in glucon

what is .groups of protozoa?

What is Cerebellum Cerebellum is situated under the cerebrum. Cerebellum has right and left lobes which are joined and form a part of pons. The function of the cerebrum is

What are autotrophic beings? What are heterotrophic beings? The Autotrophic beings are those that can produce their own food that is that make organic material from inorganic c