symbiotic and non symbiotic nitrogen fixation.pptx

Symbiotic relationship is two organism live in association with other organisms,each deriving benefit out in this relationship.
The bacteria involved in symbiotic and non symbiotic nitrogen fixation are explained. A symbiotic relationship in soil is organism of different species live together and benefit from each other. Non-symbiotic nitrogen fixation is a relationship between free living bacteria and soil that involves the bacteria fixation nitrogen from the atmosphere.

1. DEPARTMENT OF MICROBIOLOGY SUBJECT: SOIL MICROBIOLOGY SUBJECT INCHARGE: SUBMITTED BY: DR. R. DINESHKUMAR, KAVIYA .A.R Assistant professor, III. B.Sc., Microbiology, Department of Microbiology Department of Microbiology, VIAAS, Sankagiri . VIAAS , Sankagiri . VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN Veerachipalayam-637 303, Sankagiri , Salem Dt., Tamil Nadu India . Affiliated to Periyar University, Salem; Recognised Under Section 2(f) & 12(B) of the UGC Act,1956)

2. SYMBOSIS AND NON-SYMBOSIS: INTRODUCTION . SYMBIOTIC NITROGEN FIXATION. NON-SYMBIOTIC NITROGEN FIXATION.

3. INTRODUCTION : Symbiosis is the phenomenon of living Together where both the parteners are benefited. The microsymbionts derive freshly prepared food from the host plant which lack in soil. The macrosymbionts get certain nutrient from soil which are not readily available such as trace elements, nitrogen, phosphorus, etc Result of interaction-roots there may or may not develop apparent symbiotic structure.

4. ( i ) Cyanobacterial Symbiosis: The term cyanobacteria is a members of cyanophyceae . They may be both heterocystous and non- heterocystous Forms. Heterocyst is the site of n itrogen fixation. Both fix nitrogen. Anabaena cicadae with coralloid roots of cycas . It is present in cortex in a well defined region which is known as algal z one. Symbiotic nitrogen fixation:

5. (ii) Bacterial Symbiosis: There are two categories of symbiosis, Does not form apparent symbiotic structure i.e.root nodules. Forms root nodules The other one enhance plant growth without entering in symbiosis.

6. Associative symbiosis: This group includes the species of Axospirillum Which are intimately associated with their host. These have been isolate from the region of Rhizoplane. As the result root nodules are not form but pictures of root hair deformation are known. It also invade cortical & vascular tissue of host.

7. Result in an increase in mineral uptake due to phytochrome production. This association bacteria called “associative symbiont”. Azospirillum with roots of corn, wheat, etc.

8. (b) Legume-Rhizobium symbiosis: Rhizobium, a soil bacterium, enters in symbiosis with Leguminous plants. It develops root nodules which are the site of Nitrogen fixation.

9. ( i )PGPR(Plant growth promoting rhizobacteria ): The bacteria which colonize the Rhizosphere of root are commonly known as Rhizobacteria . T he non-symbiotic beneficial rhizobacteria which affect the plant growth favourably are called PGPR. The PGPR have been discovered by Kloeppler et al. Non-symbiotic nitrogen fixation:

10. PGPR belong to genera of Pseudomonas, Bacillus and Streptomyces, and most of them are fluorescent Pseudomonads. The other types are non-fluorescent pseudomonads, e.g. Serratia and Arthobacter . The most common species of Bacillus are, B.polymyxa , B .circulans and B.macerens .

11. These bacteria increase the growth of host plant. Due to a) Changes in balance of rhizhosphere microflora producing and indirect effect on the crop. b) Controls of pathogens in the rhizospere . c) Production of growth hormones. d) Release of nutrient from soil. e) Possible production of vitamins or conversion materials. f) Possible nitrogen fixation by rhizobacteria .

12. (ii) Actinomycete -Non-legume symbiosis: The species of Frankia are known to develop nodules Which are known as actinorhiza . Nitrogen fixing nodulate non-legumes are: The species of Alnus , Casuarina, Hippophae , Myrica , etc., These plants grow in such a condition where the Concentration of nitrogen is low.

13. Reference Book: Dr. R C Dubey , Dr D K Maheshwari , A TEXTBOOK OF MICROBIOLOGY S. Chand publishing Kanika Sharma , A Textbook of Microbiology . Ane Books Pvt.Ltd .

14. Thank you KAVIYA .A.R III. B.Sc., Microbiology , Department of Microbiology, VIAAS, Sankagiri .