Question

Nodulated roots are characteristic of family
A)Fabaceae
B)Asteraceae
C) Poaceae
D)Solanaceae

Answer 1

Hint:Nodulated roots are bead-like structures on the roots and found in plants that are associated with rhizobium, the symbiotic nitrogen fixing bacteria.

Complete Answer:
Nodulated root is the character of the pea family or leguminosae family because nodules are found for nitrogen fixation. The host plant developed specialized organs called root nodules. The host plants are mostly legumes in which symbiotic microorganism, generally a diazotrophic bacterium, reduces to ammonium. Nodulation is a host-specific process with each rhizobium having defined host-plant range.

Nitrogen fixation occurs in fixation threads. The nodulated roots are the characteristic of solanaceae. The solanaceae are based on genotypes from three important groups. (aubergines, capsicums and tomatoes). On all genotypes, the initial root system was complemented by a strong adventitious system emerging near the plant collar, made up of a set of fast growing roots with large apical diameters.

In the solanaceae family, there is a branched tap root system and the stem are aerial, erect and climbing (solanum jasminoides). The roots of pea and other leguminous plants have numerous swollen nodules on fine branches of roots. These nodules are formed due to symbiotic association of rhizobium (bacterium) that live inside the root cortical cells of the roots. They fix nitrogen. An active nodule is pink in colour.

Therefore, from the above explanation the correct option is (D) solanaceae.

Note:Rhizobia are diazotrophic bacteria, and it is a genus of gram-negative soil bacteria that fixes nitrogen.