Blue-green algae, also known as cyanobacteria, are photosynthetic bacteria that produce oxygen. They possess chlorophyll and can fix nitrogen. Azolla is an aquatic fern that has a symbiotic relationship with nitrogen-fixing cyanobacteria. It grows easily and can be used as green manure to improve soil nutrition. Both blue-green algae and Azolla are important for agriculture - blue-green algae fix nitrogen while Azolla acts as a biofertilizer when used in rice fields and on other crops.

1. BLUE GREEN ALGAE
&
AZOLLA
Centurion University of technology & management

2. BLUE-GREEN ALGAE

3. Introduction…
 These are phylum of bacteria that obtain their energy through
photosynthesis and are only photosynthetic prokaryotes able to
produce oxygen.
 First these were placed under algae after Whittaker five kingdom
classification they came under Phylum bacteria. So also called
“Cyanobacteria” or “Cyanophytes”.
 The name “Cyanobacteria” comes due to the presence of blue
phycobiliproteins, phycocyanin & allophycocyanin.

5. Cellular characteristics
Apart from sharing the other basic cellular features of other bacteria,
cyanobacteria possess unique and diagnostic characteristics, such as :
 Cell wall is of Gram-negative type.
 Cell division mostly by binary fission.
 Fimbriae occur abundantly with diverse patterns.
 In cytoplasm they posses chlorophyll(Chl-a) rather than bacteriochlorophyll.
 They have various components & inclusions which includes glycogen granules,
cyanophycean granules, carboxysomes(polyhedral bodies),
polyphosphate(volutin) granules & gas vacuoles. Heterocyst, akinetes &
hormogonia are some specialized cells are present.
 the chief physiological characteristics is the presence of dual photosystems that
allows the use of H2O as photo reductant with the consequent reduction of O2.

8. Importance…
1. They are one of the early colonizers of bare and barren areas. They provide suitable
conditions for the growth of other organisms even in the most hostile environment.
2. Blue green algae function as food to several aquatic animals. Spirulina is the richest
source of protein mainly consume by Astronauts. Anabaena & spirulina are used as
fodder & manure at some places.
3. Several cyanobacteria(heterocyst's) have the ability of nitrogen fixation. E.g.,
Nostoc, Anabaena. They also used for reclaiming usar soils.
4. Antibiotic can be manufactured from extract of Lyngbia.
5. Species of Anabaena & Aulosira do not allow mosquito larva to grow.
6. They produce water blooms, imparting bad odor & color to water bodies.
7. Cyanobacteria produce toxins harmful to aquatic animals. E.g., Macrocytic
aeruginosa, Anabaena flosaquae, Aphanizomenon flos-aquae.

9. AZOLLA

10. Introduction…
 Azolla is an aquatic fern regarded as “Live Nitrogen
manufacturing Factory” because it harbors nitrogen fixing
Cyanobacteria.
 It also known as Mosquito fern, duckweed fern, fairy moss,
water fern.
 It 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.

12. Characteristics…
 It is an aquatic fern consisting of a short, branched, floating stem, bearing
roots which hang down in the water.
 The leaves are alternatively arranged consisting of thick, aerial dorsal lobe
containing chlorophyll and larger thin colorless floating ventral lobe.
 Reddish-brown color Azolla due to anthocyanin pigment.
 Triangular or Polygonal in shape, floats on surface of water individually or in
mass.
 It reproduces both sexually & asexually.
 Azolla has a symbiotic relationship with nitrogen fixing blue green
algae(fern provides nutrients & protect cavity in each leaf to BGA in the
exchange for fixed atmospheric nitrogen).
 It is generally found in ponds, ditches & rice fields of warm temperature &
tropical region.

15. Uses & Advantages of Azolla…
1. It easily grows in wild environment and even can be grown under
controlled environment like polyhouse and greenhouse.
2. It can be grown in large quantities, if requires and used as green manure.
3. It can fix atmospheric CO2 and nitrogen and carry out photosynthesis and
uptake nutrients from its surrounding environment through its root
system.
4. Improve the nutritional status of the soil.
5. It also used for the production of hydrogen fuel, production of biogas.
6. It can be used as animal feed a human food, medicine and water purifier.
7. The application of Azolla as biofertilizer on agriculture crops.
8. It has wide range of use including fodder for dairy
cattle,pigs,chicken,ducks and fish.

17. Sources:-
Textbook of Microbiology by DK Maheswari
en.m.Wikipedia>wiki>cyanobacteria/Azolla
researchgate.net/sub/Cyanobacteria