Question

Nodulated roots bearing family is
A. Mimosoideae
B. Caesalpinioideae
C. Papilionoideae
D. Solanaceae

Answer 1

Hint: Root nodulation is a unique developmental process that predominantly occurs in leguminous plants and in this process, signaling initiated by symbiotic bacterial infection alters the fate of differentiated cortical cells and causes formation of new organs.

Complete answer:
Nodulated roots are defined as "the roots having the irregular or the round mass or a lump called nodules within the cells."
They are commonly found in nitrogen fixing plants.
Nitrogen fixing plants belong to the family of fabaceae.
Fabaceae includes lentils, beans etc.
The Fabaceae family is rich in nitrogen, and hence proteins.
Proteins are important requirement of human body and various organisms
Nitrogen fixing organisms take atmospheric nitrogen, and convert it into ammonia.
Examples of nitrogen fixing organisms are - rhizobium and azotobacter.
Root nodules or swellings are found on the roots of plants in subfamily Papilionoideae of family Fabaceae or also called Leguminosae (e.g., pea, gram). These nodules contain symbiotic relations with nitrogen-fixing bacteria which convert nitrogen gas from the atmosphere into ammonia. This process is called nitrogen fixation.

Thus the correct option is C. Papilionoideae

Note:
Nodule formation is regulated by chemical signals between plants and microbes, and is one of the most well-studied chemical interactions. The first step of the nodule formation starts with the leguminous bacterium receiving a signal from the host plant. The signal molecules are mostly flavonoids and their glycosides, and their biosynthetic precursors like chalcones.