Tag: biofertilizers

Azolla pinnata is an aquatic fern, which contains a nitrogen-fixing cyanobacteria. It contains Anabaena azollae in its leaf cavities. It is an excellent biofertilizer for paddy fields because they can fix nitrogen in moist condition also.

The pink color, typical of healthy and effective nodules, is due to the presence of a protein called leghemoglobin. This special protein contains Iron (Fe) and molybdenum (Mo) and is responsible for binding oxygen. This provides sufficient oxygen for the metabolic functions of the bacteroids but prevents the accumulation of free oxygen that would destroy the activity of nitrogenase.

Bacillus thuringiensis (Bt) is commonly used as a biopesticide. It is sporulating, a gram-positive facultative-aerobic soil bacterium. It synthesizes the proteins known as delta endotoxins or cry proteins which infect the insects by paralyzing the digestive tract and makes it porous.

Anabaena is a cyanobacteria. It has ability to fix atmospheric nitrogen. It converts nitrogen into ammonia. The heterocysts present in it are specialized cyanobacterial cells for nitrogen fixation. It contains enzyme nitrogenase. Nitrogenase is inactivated by oxygen. Hence, the heterocyst creates a micro anaerobic environment.

A membranous coiled semicircular structure attached to plasma membrane and found in blue-green algae is called as Lamellasome. It is approximately 200 mμ in diameter. Mesosome is folded invagination found in the plasma membrane of bacteria that increases the surface area. They are the site of respiration. Microsome is a fragment of endoplasmic reticulum. It is an artificial structure and is not present in living cell.

Blue-green algae are also called as cyanobacteria. The blue colour of blue-green algae is due to presence of pigments phycocyanin and allophycocyanin. The green colour is due to presence of chlorophyll pigment. Phycoerythrin pigment results in the red colour. Anthocyanins pigment gives red, purple and blue colours in many fruits and vegetables. Anthoxanthin pigment gives white or colorless to a creamy to yellow color to petals of flowers.

Cyanobacteria are also called as Blue green algae. They are prokaryotic bacteria. They are nitrogen fixing bacteria. They are capable of fixing atmospheric nitrogen into ammonium compounds and making it available to the plants. They are useful bifertilizers in fields of rice for cultivation. They are used either free-living and in symbiotic association.