Question

In dahlia the roots are
A. Fibrous
B. Stilt
C. Moniliform
D. Fasciculated tuberous

Answer 1

Hint: Adventitious roots occur in dahlia in clusters and all these are swollen. In dahlia these roots lie at the base of stem and are fleshy in nature In dahlia such types of roots present as a modification for food storage and such types of roots have definite shape.

Complete answer:
Usually it is said that the root is the part of the plant that is left in the soil. But there are air and sub aerial roots. In fact, the root is a positive geotropic part of the plant with a root cap and numerous unicellular root hairs. Ontogenically, the root comes from the radical.
Fibrous root-These are underground roots that appear in groups of knots on horizontal stems . The main roots are the same length. They give small twigs. Both the main roots and branches are thin and threadlike. Hence they are called fibrous roots. The fibrous roots do not penetrate deep into the soil. They remain close to the ground level and are known as surface elevators.
Stilt roots-Some shrubs and small trees, such as Scotch pine (Pandanus foetidus), grow along the edges of bodies of water, marshes, etc., where the anchors are not very strong. In this case, short roots grow at the base of the stem, providing additional support and serving as a platform to hold the stem.
Moniliform roots- Roots periodically swell like a pearl necklace, for example Basella (Portulaca), Momordica, rubra, and some grasses.
Tuberous root-In plants like sweet potato growing at the soil surface, some random roots that grow from the stem become swollen and fleshy for food storage. They do not have regular shape . They are called tuberous roots.
Fasciculated root- In asparagus An appreciable number of tuberous roots from the stem, forms bundles or fasciculus. This is called the root fasciculation and roots are called Fasciculated roots. Other examples of Fasciculated roots are Dahlia and Ruellia (Menow weed).

Hence, from the above points it’s clear that the correct option is (D).

Note: Dahlias are round-rooted perennials, although they are grown annually in some areas with cold winters. While some have herbaceous stems, others have lignified stems in the absence of secondary tissue and reappear after hibernation, allowing a further growing season.
In dahlia roots are a modification of adventitious roots.