The genus Azospirillum includes free-living, nitrogen-fixing bacteria known as plant-growing rhizobacteria (PGPR), which can colonize the root surface or intercellular spaces of the host plant roots through adhesion. PGPR's potential role in association with economically important cereals and other grasses is to promote plant growth through multiple mechanisms including nitrogen fixation and development of phytohormone. Many Azospirillum species are able to secrete phytohormones such as auxins, gibberellins, cytokinins, and nitric oxide as signs of promoting plant growth.

Physical features of liquid Azospirillum:

1. The water may have a blue or dull white colour.

2. Poor odours indicate the wrong composition of liquids and can be inferred as pure broth.

3. The quality product is confirmed by the production of yellow gummy colored materials.

4. Acidic pH also indicates that the water does not contain any Azospirillum bacteria.

5. N2 repairing Azospirillum potential in the roots of several plants and the quantity of N2 that they restore.

Advantages:

1. Azospirillum, an associate nitrogen fixer, replaces the root layer with atmospheric nitrogen, which the plants take up.

2. It also secretes growth hormones that stimulate the production of the heart.

3. It also produces growth-promoting substances such as Indole Acetic Acid (IAA), gibberellins, pantothenic acid, thiamine and niacin, encouraging root proliferation and improving the yield of plant growth.

4. This increases the density of the rootlet and the root branching resulting in increased mineral and water absorption.

Mode of Action:

Due to the strong triple bonds between the nitrogen atoms, nitrogen cannot be absorbed by plants making it inert and therefore not assumable by plants.

Bio Active compound synthesis: Azospirillum lipoferum produces growth-enhancing substances such as indole acetic acid (IAA) and gibberellins that encourage root proliferation and increase rootlet density and root branching, leading to increased mineral and water consumption.