Question

Pappus is a modification of
A. Bracts
B. Corolla
C. Calyx
D. All of the above

Answer 1

Hint: The pappus is the hairy structure that helps in the dispersion of seeds. These are the characteristic properties of the family Asteraceae. The pappus is a modification of sepals that are part of an individual floret surrounding the base of the corolla in the flower head.

Complete answer:
In the flower-producing plant family called Asteraceae a characteristic structure composed of bristles, awns, scales, etc are present. These are called pappus. They are usually hairy in appearance. For example, in the tridax flower, a feathery, plume-like structure having stiff hairs covers the fruit. This structure is called a pappus.
-The pappus is an important structure involved in the wind-aided dispersal of seeds of flowers in which it is present. The flight of the pappus is stabilized by the creation of a separated vortex ring. This produces more lift and drag. Also, in the presence of moisture, the pappus changes its morphology that aids in the germination of seed enclosed in it. The change in the shape of the pappus controls the rate of abscission. This allows increased or decreased germination depending on the favorable conditions.
-The pappus is the modification of the calyx or sepals. The calyx forms a whorl of sepals that encloses the petals. The function of sepals is to provide a protective layer around a flower in the initial stages. This calyx is highly modified in Asteraceae that they are signified individually as a pappus.
Now, let us discuss the other given options.
-The bract is a modified leaf associated with a reproductive structure like a flower. The bracts are different from the foliage leaves. They are not involved in pappus formation.
-The corolla is the petals of a flower. They form a whorl bounded by the calyx. The corolla encloses the reproductive organs of the flower. They have no associations with pappus.
Hence, the right answer is option C.

Note: The dandelion pappus has been studied extensively and reproduced for a variety of applications. Their special property of retaining 100 times its weight in water has inspired various mechanisms resulting in highly efficient liquid transport systems. Thus, it is an important structure both biologically and economically.