Question

Girth of stem increases due to __________.
A. Apical meristem
B. Lateral meristem
C. Intercalary meristem
D. All the above

Answer 1

Hint: Increase in girth of the stem is the lateral growth of plants due to tissues that are found beneath the bark of a tree.


Complete answer:
The girth of stem increases due to lateral meristem found in cork cambium.

Additional Information:
> Growth of plants includes primary growth (increase in the length of stem and root) and secondary growth (increase in thickness). Primary growth is usually due to cell division in the apical meristem and secondary growth is due to cell division in the lateral meristem.
> Lateral meristematic tissues are found as a thin layer in cork cambium and vascular cambium of dicot plants. That helps in the increase of girth of the plant.
> Apical meristem is situated at growing tips of plants like the tip of the root, shoot, and a piece of the leaf. It helps the plant to elongate by increasing its height (primary growth).
> The intercalary meristem is located at the base of the leaf and in the internodes. It helps in the increase in the length of plant organs like nodes and internodes.
> Apical and intercalary meristem is found in both monocot and dicot plants, whereas lateral meristems are only found in dicot plants.

Note: Annual rings or annual growth rings are the lateral growth (increase in girth) in the trunk of a tree that provides the scientist with knowledge about the lifespan of a tree. This annual ring is a result of the activity of the vascular cambium. The rate of lateral growth of the trunk increases in summer and decreases in winter, producing a characteristic ring for each year of growth. Thus, the count of growth rings in a tree trunk gives us the age of a tree.