Question

In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order.
A. Cell division, cell enlargement, cell maturation, root cap
B. Cell division, cell maturation, cell enlargement, root cap
C. Root cap, cell division, cell enlargement, cell maturation
D. Root cap, cell division, cell maturation, cell enlargement

Answer 1

Root is defined as the structure that helps in absorption of water and minerals. Root is covered with root apical meristem that is cells of root are in continuous state of cell division. It transports water and minerals towards the upper side of the plant.

Complete answer:
Roots are cylindrical, underground and non-green parts of the plant. It is generally the descending portion of the plant axis i.e., it grows downward into the soil. It lacks nodes, leaves, buds but gives rise to endogenous lateral branches. Root has many different regions:
A. Root сар : The apex of the root is covered by a thimble-like, structure called root cap. It is multicellular and is made up of parenchymatous cells. It protects the tender apex of the root as it makes its way through the soil.
B. Region of meristematic activity: This layer is few millimetres above the root cap. The cells of this layer are thin-walled, small, with dense protoplasm. They divide repeatedly to produce new cells.
C. Region of elongation : The cells proximal to the meristematic region undergo rapid elongation and enlargement and are responsible for the growth of roots in length.
D. Region of maturation : The cells elongation zone gradually differentiate and mature. Hence, this zone, proximal to the region of elongation, is called the region of maturation. Some epidermal cells from the region of maturation form very fine and delicate thread-like structures called root hair. The root hair increases the surface area for absorption of water and minerals from the soil.

Hence, the correct answer is option (C).

Note: Roots move in the direction of gravity (geotropism) and against the direction of light (phototropism). Hence, the roots are said to be positively geotropic and negatively phototropic. Roots have many functions such as providing anchorage to plant parts and storage of reserve food material.