Factors Affecting Nodule Formation

Factors Affecting Nodule Formation:- Nodulation is affected by both external and internal factors. External factors include heat, acidity, nitrate content of the soil, etc.

i. If soil is rich in nitrogen content, it interferes with the nodule formation and symbiotic association as plants already have enough nitrogen and they do not need more.

ii. Nitrogen fixation is an oxygen-sensitive process. The root nodules contain a heme pigment called leghaemoglobin, which facilitates the diffusion of oxygen.

iii. Nodule formation is auto regulated by leaf tissues. Plants have evolved defense mechanisms to check the infection.

iv. Ethylene also regulates nodule formation internally. Exogenous application of ethylene has shown to inhibit nodule formation.