Question

Assertion: Apical and intercalary meristems contribute to the growth in length, while the lateral meristem brings an increase in girth in maize.
Reason: Apical and intercalary meristems always increase the height of plants.
A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C) The assertion is correct but the Reason is incorrect
D) Both Assertion and Reason are incorrect

Answer 1

Hint: Apical meristem is present at the root and stem tips. The intercalary meristem is the meristematic cells present between the permanent tissue regions in plants. The lateral meristem forms the girth of a plant.

Complete answer: The tissues present in plant cells are of two types of permanent tissues and meristematic tissues. Permanent tissues are a group of tissues that are inactive and do not divide. Meristematic tissues comprise dividing cells. They are active and keep on dividing continuously. Meristematic cells are also known as meristems that are mostly young. These cells have a thin cell wall, abundant protoplasm and a prominent nucleus. On the basis of position, the meristem is classified into apical meristem, intercalary meristem, and lateral meristem.
a) Apical meristem is found at the tip of the stem and root. It is responsible for the growth of the length of shoot and roots of the plant also known as primary growth.
b) Intercalary meristem is found intercalated or between permanent tissues. It helps to increase the height of the plant. Intercalary meristem is present only in monocots.
c) Lateral meristem is found along the sides of the plant. They appear only on the maturation of the plant’s body parts. They are responsible for secondary growth in plants, for example, a girth in plants.
The apical and intercalary meristem is involved in the growth of plants, while the lateral meristem brings about an increase in the girth, but there is no secondary growth observed in a maize plant.
Hence, the correct answer is option D.

Note: Mostly in tissue culture, the meristem culture is used for cloning, i.e. the formation of a new plant from meristematic tissues. As the meristem culture does not contain vascular tissues, there is no contamination that occurs due to viruses or other pathogens.