Question

Bamboo and grasses elongate by the activity of
A. Secondary meristem
B. Lateral meristem
C. Apical meristem
D. Intercalary meristem

Answer 1

Hint: Meristematic tissues include a group of cells that are always in a perpetual stage of cell division. Based on the position of the meristematic tissues in plants, we can divide them into several types.

Complete answer: Intercalary meristem is made up of the left out parts of the apical meristem. They are seen between the permanent tissues. Examples of intercalary meristem are the stem elongation seen in bamboo, grasses, the stem of wheat, etc. It is made up of meristematic cells that divide mitotically in the stem at the base of nodes and leaf blades. This type of meristem only occurs in monocots.
i. Lateral meristem brings lateral growth in gymnosperms and dicotyledonous plants. The secondary growth is responsible for the lateral growth of the plant which helps to increase girth. The apical meristem is responsible for primary growth. The lateral meristem consists of two types of tissues. They are vascular cambium and cork cambium. Vascular cambium is responsible for the production of a vascular bundle. In dicot stem, cambium which is present between the primary xylem and primary phloem is called intrafascicular cambium. So the cambium of the vascular bundle of dicot plants is called fascicular cambium. It is seen initially as patches. Gradually, cells that are present next to the intrafascicular cambium called medullary rays become meristematic and together form a ring structure.
ii. Apical meristem is a type of meristematic tissues that are seen in the apices of plants. They are seen both in the shoot apex and the root apex. The shoot apex is called an apical bud.
Hence the correct answer is option D.

Note: Meristems are undifferentiated tissues present in plants. The intercalary meristem is located at the internodes of plants. These are the sites at which leaves attach to the stem or branch. Intercalary meristem is also seen at the leaf bases.