Question

Which one of the following pairs is an example for lateral meristem?
A. Phellogen and phelloderm
B. Phellogen and fascicular cambium
C. Procambium and phelloderm
D. Interfascicular cambium and phellem

Answer 1

Lateral meristem is that tissue that helps in increasing the girth of the plant. It consists of various types of cambium. Moreover, the cambium is the tissue that is made up of meristematic cells which divide very actively to facilitate the lateral growth of the plant.

Complete answer: The Lateral meristem is the meristematic tissue that is situated at the peripheral zone of the plant, i.e., the roots and the stem. The lateral meristem is the tissue that is responsible for increasing the lateral width of the plant. Therefore, it helps in the secondary growth of the stem. The examples of the lateral meristem are the vascular cambium, interfascicular cambium, and the cork cambium. Secondary growth occurs due to the activity of the secondary meristem, i.e., the cambium and the cork cambium. The fascicular and the interfascicular cambium fuse to form the cambium ring. The fascicular cambium is also known as the vascular cambium or the Interfascicular cambium. The cells of the cambium ring produce the new cells on the inside and the outside surface of the cambium ring. The cells formed inside are known as the secondary xylem whereas the cells formed on the outside are known as the secondary phloem. This cambium ring then shifts outwards increasing the diameter of the stem. The cork cambium ring is formed from the cork cambium cells. It is also known as the phellogen. It helps in the development of the periderm. This is because it grows outwards to form the cork and it grows inwards to form the secondary cortex. All these three layers together form the periderm. Thus, based on the above information we can conclude that the phellogen and the fascicular cambium are the examples for the lateral meristem.
Hence, the correct answer is option (B).

Note: The periderm consists of three layers namely cork, cork cambium, and the secondary cortex. The cork is also known as the phellem. It is dead tissue due to the presence of the suberin on the walls. The cork cambium is also known by the name of phellogen. Lastly, the secondary cortex is also known as the phelloderm.