Question

The stem of grasses and related plants elongate by the activity of
A. Apical meristem
B. Lateral meristem
C. Intercalary meristem
D. Both apical and intercalary meristem.

Answer 1

Hint:-Meristematic tissue is the type of tissue found in the plants at the point of growth like at the root and the shoot tips. Meristematic tissue consists of undifferentiated cells. These cells are capable of cell division. These cells are also referred to as temporary cells. Lateral meristem is the type of meristematic tissue that is placed in parallel to the circumference of the plant.

Complete answer:
Lateral meristem consists of actively dividing cells and is responsible for the increase in the girth or diameter of the plant. Apical meristem is present at the apex points of the plant-like tips of the shoots and roots. It results in the longitudinal growth of the plant. It consists of cells that divide mitotically very rapidly. They keep dividing until they become permanent and incapable of further division. This is the point of differentiation.
Apical meristem is a primary meristem. Apical meristem can also be referred to as the ‘growing tips’ of the plant. An intercalary meristem is present at the end of the nodes in the plant. It is present in between the mature tissues. It is also present at the base of stems and stalks. The intercalary meristem along with the apical meristem is responsible for the growth of the plant along its length.

Thus, the correct answer is Option (D) - Both apical and intercalary meristem.

Note:- Once the tissue differentiates, it is no more capable of dividing. It forms a permanent tissue. The growth rendered by the apical and the intercalary meristem is a type of primary growth. The secondary growth in plants is in the lateral direction leading to the thickening of the plant that is provided by the lateral meristems.