Question

Complementary cells are formed by the activity of :

• A. Phellogen
• B. Interfascicular cambium
• C. Intrafascicular cambium
• D. Vascular cambium

Answer 1

The correct option is A Phellogen

The complementary cells are formed from the cork cambium (phellogen) at the position of the lenticels. It is a group of loosely arranged cells that aid in gaseous exchange through cork.

When the outermost layer of cortex or hypodermis become meristematic, it transforms into Phellogen or cork cambium. It can be differentiated into complementary cells, situated inside the lenticels which doesn't contain the coating of suberin. Thus the gaseous transport can occur through the lenticels.

The vascular cambium is responsible for increasing the diameter of stems and roots and for forming woody tissue. In a dicotyledonous stem, the primary xylem and primary phloem are separated by cambium cells called intrafascicular cambium. During secondary growth, the medullary rays adjacent to the intrafascicular cambium develop into meristematic tissue and are called interfascicular cambium.

So, the correct answer is "Phellogen".