What is biofertilizer?(b) Draw and label the T.S. of root nodules.

Answer:

(a) Biofertilizers are living microorganisms (bacteria, cyanobacteria, fungi) that enrich the soil with nutrients such as nitrogen and phosphorus, e.g. Rhizobium, Azotobacter, Anabaena, mycorrhiza.

(b) [Figure: T.S. of a root nodule of a legume — outer cortex (nodule cortex), vascular strands (vascular bundles) in the cortex, central infected zone of large cells filled with bacteroids (Rhizobium), pinkish due to leghaemoglobin, with some uninfected cells; outer epidermis/periderm.]

Labels: epidermis, cortex, vascular bundle (vascular strand), infected cells containing bacteroids (Rhizobium), leghaemoglobin (pink region).