Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern. Azolla (mosquito fern, duckweed fern, fairy moss, water fern) is a genus of seven species of aquatic ferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling duckweed or some mosses.

1. ANABAENA & AZOLLA
Paradava Jaydip
Sardar Patel university

2. ALGAE : ANABAENA
• Anabaena is a genus of filamentous cyanobacteria, or
blue-green algae.

3. STRUCTURE OF ANABAENA
• It has filamentous structure. Its filament resembles the filament of Nostoc.
• The filaments of Nostoc are covered by mucilage and form a colony which is
absent in Anabaena. The filament of Anabaena consists of string of beaded cells.
• Several intercalary heterocysts are present in the trichome.
• Heterocysts are of same shape as of vegetative cell.
• The filaments are ordinarily straight. But they may be circinate or irregular.
• Filaments occur singly within a sheath. Sheaths are always hyaline and watery
gelatinous.

4. ITS CELLS HAVE FOLLOWING
COMPONENTS:
• Each cell has outer cell wall. This wall consists of three layers.
• The inner layer is thin cellular layer, medium is pectic layer and outer is
mucilage layer.
• The peripheral of the protoplasm is composed of part called chromoplasm.
It contains pigment. Hence it is colored. The central colourless part of
protoplasm contains nucleus like material called central body or chromatin
granules.
• Heterocysts are of same shape as of vegetative cell.
• Golgi bodies, encoplasmic reticulum and mitochondria are absent in their

5. • Heterocysts are the point at
which the filament breaks into
hormogones.
• Heterocysts convert nitrogen
into ammonia.
• Hormogones may also formed
by the breaking of filament or
decay of filament at some other
points.

8. AZOLLA
• Azolla /mosquito fern/ duckweed fern/
fairy moss/ water fern is a free floating
aquatic ferns and is genus which belongs
to family Salviniaceae.
• It grows in fresh water and is naturally
available mostly on moist soils, ditches
marshy ponds and is widely distributed in
tropical belts of India.

9. STRUCTURE OF AZOLLA
Shape of Indian species is typically triangular measuring about 1.5
to 3.0 cm in length 1 to 2 cm in breadth.
• Roots emanating from growing branches remained suspended in
water.
• The dorsal lobe which remains exposed to air is having a specific
cavity containing its symbiotic partner, a Blue Green Algae (BGA),
the Anabaena azollae.
• The fern is capable of fixing atmospheric nitrogen in the soil in the
form of NH4+ and becomes available as a soluble nitrogen for the
cultured species.

10. • Classification (Taxonomy)
• Kingdom : Plantae
• Division :Pteridophyta
• Class : Polypodiopsida/
Pteridopsida
• Order : Salvinales
• Family : Salvinaceae
• Genus : Azolla
• Sub Genus : Eu-Azolla

11. REQUIREMENTS FOR AZOLLA GROWTH
Water: 10-15 cm fresh current water is necessary in multiplication
pond. Maintenance of adequate water level (at least 4 inches in the
pond) is essential.
Temperature: Day/night temperatures ranging between 32ºC and 20ºC
have found to be most favorable. The optimum temperature for
luxurious growth of Azolla is 25-30˚C.
Light: It prefers to grow well under partial shade.
Relative Humidity: The optimum relative humidity requirement is 85
to 90 per cent.
Soil pH: Azolla grows well in slightly acidic soil having 5.2 to 5.8 pH.
Nutrition: Being an N fixing fern Azolla does not require nitrogenous
fertilizer for its growth. Phosphorous @20 kg/ha is desirable for good
bio-mass production.

12. Steps of Azolla Culture
Selection of pond location
Pond size and construction
Production of Azolla
Maintenance of the pond
Harvesting and feeding
Yield of Azolla
Economics of Azolla Cultivation

13. LIMITATIONS OF
AZOLLA CULTIVATION
• Water is pre-requisite for it’s multiplication . so it is not
suitable for upland crop.
• Huge quantity of inoculums is required which is difficult for
transplanting action during rainy days.
• Temperature more than 35°C is not suitable.
• Extreme low temperature is also not suitable.
• Non availability of technology to use Azolla as dry inoculum.
• Non availability of varieties suitable for higher temperature
with low pH application.
• Initial cost of cultivation is high. Market for azolla is not so
popular.
• Ignorance of people about benefit of Azolla.