Question

Find the incorrect statements from the following.
A. Roots hairs are a multicellular elongation of the epidermal cells.
B. Trichomes are unicellular epidermal hairs of the stem.
C. Guard cells are specialized cells regulating the opening and closing of stomata.
D. Cuticle, collenchyma, and stomata are absent in roots.
(a) A, C and D are incorrect
(b) B, C, and D are incorrect
(c) A and B are incorrect
(d) B and D are incorrect

Answer 1

Hint: Root hairs are associated with epidurals cells and are responsible for the absorption of water and minerals. Trichomes are fine outgrowths present all over the body of a plant. Guard cells are the cells that enclose the stomata between them.

Complete Answer:
Root hairs: A root hair is the outward projection of the epidermal cells and thus it is a unicellular elongated structure. This is where most water absorption takes place as it has a large surface area and can penetrate deep into the soil.
Trichomes: Trichomes generally refer to outgrowths that range from small hairs to large thorns but usually trichomes are used to refer to the tiny hairs that emerge from leaves or any epidermal surface of the plant. It can be either unicellular or multicellular.
Guard cells: Guard cells are responsible for the opening and closing of stomata. Stomata are small pores present in between the epidermal cells that allow the exchange of gases and transpiration. Subsidiary cells are present around stomata and get specialized to help it. Stomata along with the guard cells and subsidiary cells make up the stomatal apparatus.
Tissues absent in roots: Cuticle, collenchyma, and stomata are not present in roots as root is present under the ground and does not require them as much as stem and leaves do.
Only the statements about guards cells and roots are correct and the other two are incorrect.
So, the correct option is ‘(c) A and B are incorrect’.

Note:
- A trichome also has a stalk that may be glandular or non-glandular in nature.
- In woody trees, lenticels are present in the bark to allow gaseous exchange.
- Lenticels are a lens-shaped opening that is formed by the breaking of the epidermis because of internal cell division.