Azolla anabaena association

symbiotic association between Azolla and anabaena

1. Azolla-Anabaena Association Dr.S.Dhiva, Department of Microbiology, S.N.College, Alathur, Kerala

2. AZOLLA Azolla is a aquatic fern, Do not survive in dryness, lives in contact with water Made of Vegetative and reproductive form forms a symbiotic association with Blue green Algae, Anabaena azollae Fixes atmospheric N 2 in the soil

3. ANABAENA AZOLLAE Anabaena Azollae is a phototrophic cyanobacteria (BGA) Small and filamentous, generally seen as a multicellular organism with two distinct, cell types. 1. “ vegetative” cell , photoautotrophic, performs oxygenic photosynthesis and appears blue green in color. 2. heterocyst ; a larger , appears pale in color, produced to fix atmospheric nitrogen.

4. Anabaena azollae-Azolla Azolla Anabaena azollae

5. Habitat A . Azollae , although free living Azolla is grown in tropical and temperate climates in undisturbed water bodies Azolla ,commonly known as waterfern whose small leaves accumulate on the surface of water bodies creating mat like structure. A. Azollae but usually found within ovoid cavities inside the leaves of the water fern Azolla.

6. ASSOCIATION Anabaena azollae receives safe environment to survive and are connected to the external environment through the pores of the leaves of Azolla Epidermal cells of the leaf forms a hair like structure which facilitates the exchange of nutrients between them A . Azollae 5-10 % of its cells into heterocysts when it is free living. Symbiotic association between Azolla and A. azollae will increase its heterocyst production up to 25-30%. Azolla is known to produce “toxic blooms” in their environment.

7. Application Used as green manure for paddy cultivation forms a dense mat over the paddy field and reduces the development of weeds Fix atmospheric Nitrogen in the soil In addition to N2 fixation, Anabaena releases Vitamin B12, Auxins , etc., which induce the growth of higher plants Acts as a active biofertilizer Increases the yield of crops In addition to fertilizer, Azolla is also used in fish food and garden mulch and natural food for various types of insects . Azolla can be used and as a water purifier and for the control of weeds, mosquitoes, reduces the application of chemical nitrogen fertilizers

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