PowerPoint Presentation On Nitrogen Metabolism

PPT On Nitrogen Metabolism

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Nitrogen Metabolism Presentation Transcript:

1. NITROGEN METABOLISM
Nitrogen Fixation can be defined as the conversion of molecular nitrogen into fixed form of nitrogen to make it available for absorption by plants. It is the third most important process after respiration and photosynthesis. It is essential for all living organisms.

2. BIOLOGICAL N2 FIXATION
Conversion of elemental nitrogen or gaseous nitrogen into nitrogenous compounds or salts by certain microorganisms like bacteria ,blue green algae, fungi etc. is called biological nitrogen fixation. It is carried by two types of micro- organisms. Eg Symbiotic and non-symbiotic.

3. NON-SYMBIOTIC N2 FIXATION
The Fixation of free nitrogen of the soil by all those micro-organisms living freely or outside the cell is called as non-symbiotic biological N2 fixation.

4. SYMBIOTIC N2 FIXATION
The Fixation of free nitrogen of the soil by microorganisms living symbiotically inside the plant, is called as symbiotic biological N2-fixation. The term “symbiosis” is coined by De bary in 1879.

5. CLASSIFICATION
Nitrogen Fixation Through Nodule Formation in Leguminous plants. N2 Fixation through Nodule formation in Non-leguminous Plants. N2-Fixation through Non-Nodulation.

6. N2-FIXATION IN NON- LEGUMINACEOUS PLANTS
In addition to legumes, there are many plants specially trees and shrubs belonging to families other than Leguminosae which produce root-nodules. Eg- Casuarina- Frankia Alnus- Frankia Myrica- Frankia Parasponia- Rhizobium

7. N2 Fixation through Non-nodulation It includes those plants where root nodules are not formed but symbiotic N2-fixation takes place. Examples- Lichens - associated with fungi and algae Azolla- Anabaena azollae. Cycas –Anabaena or Nostoc Gunnera macrophylla- Nostoc

8. Associative Symbiotic N2-Fixation
When the bacteria live in close association with the roots of cereals and grasses and fix nitrogen than the association is of loose mutualism type and is called associative symbiosis whereas this nitrogen Fixation is called associative symbiotic nitrogen fixation. Examples- Azotobactor paspali – Associated with Paspalum notatum Azospirillum brasilense- Cereal roots Beijerinckia- Sugarcane roots

9. LEGHEMOGLOBIN
The red pigment of the nodules is called leg-hemoglobin and appears to be a product of the Rhizoboium-legume complex. The pigment is not present in either organism grown alone. It is a reddish pigment found in the cytoplasm of host cells. It is an oxygen carrier & an efficient O2 scavenger

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