Nitrogen Fixation - Plant physiology - Very important points | Vbiotonic for NEET

Nitrogen Fixation - Plant physiology -
Very important points

Nitrogen fixation - Nitrogen fixing bacteria

(A) Symbiotically – Some bacteria live symbiotically and do nitrogen fixation.
e.g. · Rhizobium – found in the root nodules of legumes
· Azorhizobium – found in the stem nodules of Sesbania plant
· Azospirillum – Found on root surface of cereals i.e., superficial symbiosis (eg. Wheat, Rice, Maize).
· Frankia (Filamentous bacteria or actinomycetes) - It is found In root nodules of non leguminous
plant Casuarina and Alnus plants.

(B) Asymbiotically – Some bacteria are found freely in soil and do nitrogen fixation.
e.g. Clostridium, Chromatium, Azotobacter, Azospirillum, Beijernickia, Rhodomicrobium, Rhodospirillum, Rhodopseudomonas

Note : Azotobacter and Beijernickia are aerobic Rhodospirillum is anaerobic bacteria, Both Rhizobium and Frankia are free living in soil, but as symbionts, can fix atmospheric nitrogen.