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 N2 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

8. Thank you