Question

For Nitrogen fixation in soil we may use ______________.

• A. Cyanobacteria
• B. Protozoans
• C. Nematodes
• D. Wheat plants

Answer 1

Answer: (A)

$\to$ Cyanobacteria

$\Rightarrow$ Importance of Cyanobacteria have the ability of

$\bullet$ Several cyanobacteria have the ability of

$N_2$ fixation. The filamentous forms fosses

Special large fale cells or heteracysts for this

$\bullet$ some of dhe fixed nitrogen comes out as Excellion

$\bullet$ After death of Cyanobacteria the substratum

becomes rich in nitrogen

$\bullet$ $N_2$ fixing cyanobacteria are often used for

reclaiming user soils.