Index >> Nitrogen Fixation Symbiotic Blue-Green Algae >> Survial of Azolla

	Survival of Azolla Survival of AzolIa after a drought period is associated with the production of sexual organs since plants die due to desiccation. The plant produces Azolla and Blue Green Algae A. Azolla Pinnata B. Nursery of A. Pinnata C. L.S. Azolla Showing Dotted Algal Cells D. Blue Green Alga Showing Vegetative Cells E. Mass Multiplication of Blue Green Algae
Effect of Azollaand N fertilizer on the yield of short duration rice variety Kalinga-2 during Rabi season (Singh, 1977) Treatments                   Grain yield               Straw yield   kg/ha*    % increase control  over kg/ha*  % increase control  over 1. Control (no Azolla) 1722 - 1325 - 2. Incorporated Azolla (10 tons fresh wt/ha) 2423 41 2087 58 3. Incorporated Azolla(20 tons fresh wt/ha) 2623 53 2587 95 4. Unincorporate Azolla(10 tons fresh wt/ha) 2400 39 2025 53 5. 20 kg N/ha (basal) 2208 28 2100 58 6. 40 kg N/ha (basal) 3187 85 3437 159 7. 60 kg N/ha (basal) 3518 104 3737 182 8. 80 kg N/ha (basal) 3894 126 4650 251 9. 30 kg N/ha+ Azolla  (10 tons fresh wt/ha) 3461 101 2837 114 10. 50 kg N/ha+ Azolla  (10 tons fresh wt/ha) 3576 108 3032 129 *Mean value  CD. (1%) 355.78 kg/ha   526 kg/ha
microsporocarps (male) as well as macrosporocarps (female). Azolla plants have the main rhizome bearing alternate secondary and tertiary branches. Sporocarps are initiated at the place of attachment of branches and replace the lower lobe of the first leaf of a branch. The dorsal lobe covers the sporocarp.
The sporocarps occur in pairs, both male and female and male plus female side by side. Macrosporocarps are really small oval-shaped with pointed ends measuring 0.75-1.0 mm in length and 0.5 mm in breadth. They are yellowish green in colour especially at the tip which becomes brown and hard due to lignification and tannin deposits. It is through the macrocarp tip that vegetative cells of Anabaena get into the plant and establish symbiosis.
	A mature microsporocarp is really larger than a macrosporocarp, globular in shape and measures about 2 mm in length and 1.5 mm in breadth. As many as 120 or more microsporangia may develop inside a single microsporocarp. Within each microsporan­gium 32-64 microspores develop. On the other hand, a mature macrocarp contains a single functional macrospore. The micro- and macrosporocarps which are seasonally produced decay and sink to the bottom of a pond or any body of water in which Azollagrows, The decay and rupture of these sporocarps results in a meshed consortium described as macrosporangium complex.

A mature microspore does not get freed from this macrosporangium complex and therefore development of micro- and macrogametophyte takes place in close proximity which makes matters easy for fertilization.

The macro­gametophyte (female) develops an archegonium (female apparatus) in which the egg cell (macrospore) is situated.

The microgametophyte formed from a microspore also remains entangled with its appendages and develops an antherdium (the male apparatus).

Fertilization of the egg cell with a spermatozoid (antherozoid) from the antherdium results in the for­mation of a zygote or embryo.

The development of the embryo takes place in the macrosporic complex and only when the seedling emerges with its cotyledons,

the unaided eye can recognize the juvenile Azolla seedling with its rhizoidal development.

The bilobed leaf formation takes place and the mature plant develops in about 21 days.