Question

Velamen and spongy tissue are found in
A. Breathing roots
B. Parasitic roots
C. Tuberous roots
D. Epiphytic roots

Answer 1

Hint: Velamen is a spongy tissue. It is present as a covering in plant-like orchids. They help absorb moisture. It involves an enlarged fleshy root modified as a storage organ with shoots produced at one end and roots produced at the other.

Complete answer: Plants that grow on other plants are called epiphytes. With an adapted root system, they bind to larger plants. In nature, most epiphytes are not parasitic and do not derive nutrients from the host plant. Orchids (family of Orchidaceae) and bromeliads (family of Bromeliaceae) provide common examples of epiphytes. Much like roots rooted in soil, epiphyte roots serve as support structures. Typical examples of this adaptation include orchid roots. The interior of the root of an orchid is called the cortex. This nourishes and is very powerful for the plant. The velamen, a substance that can adhere to almost everything, is sealed. Velamen is also effective in removing moisture or any nutrients, such as minute traces of leaves and other debris, present in the host plant. Spongy tissue is formed by the epiphytic roots of orchids to absorb humidity and nutrients from any organic material on their roots. So, in epiphytic roots, velamen and spongy tissue are present and missing in breathing roots, parasitic roots and tuberous roots.
So, the correct answer is option D.

Note: A breathing root is an aerial root – it can be described as a root that is exposed to the air, at least for part of the day. For example, the roots of mangrove trees. A tuberous root is an expanded fleshy root. It is modified by shoots produced at one end and roots produced at the other as a storage organ. Example: sweet potato.