EVERYDAY SCIENCE

Detailed explanation-1: -The Rhizobium or Bradyrhizobium bacteria colonize the host plant’s root system and cause the roots to form nodules to house the bacteria (Figure 4). The bacteria then begin to fix the nitrogen required by the plant.

Detailed explanation-2: -Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria, such as Azotobacter, and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.

Detailed explanation-3: -The symbiotic nitrogen-fixing bacteria invade the root hairs of host plants, where they multiply and stimulate formation of root nodules, enlargements of plant cells and bacteria in intimate association. Within the nodules the bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development.