How do Root Modules Form?
Plants need products derived from nitrogen; however, they cannot use free nitrogen in the air. How do they solve this issue? One of the best events in nature is when two different organisms team up and look out for one another. This is referred to as symbiosis. Plants like peas team up with a soil bacterium called Rhizobium. These bacteria can use nitrogen from the air to make compounds that plants can use, using enzymes. Enzymes are chemicals that give a push to chemical reactions, and are synthesized by living organisms.
The process begins when thin strands of roots, called root hairs, release certain chemicals into the soil, and this attracts the bacteria. The bacteria accumulate near the root hair and form a tube. The bacteria enter through this tube to cause an infection. Due to this infection, outgrowths called nodules are formed. These nodules contain bacteria, and they absorb and use atmospheric nitrogen to make various nitrogenous compounds that plants can use for their nutritional needs. In other cases, no such nodules are formed but infection still takes place.