Question

In primary growth, epidermis is the outermost covering of the stem. During secondary growth, due to the activity of cork cambium and vascular cambium the epidermis in primary growth is replaced by a structure known as

• A. Periderm
• B. Phelloderm
• C. Phellogen
• D. Periblem

Answer 1

Answer: (B)

Phelloderm

1. Phellogen, phellem, and phelloderm are collectively known as periderm and replaces the epidermis of the plant body.
2. Phelloderm is the thin layer of tissues developed in the inner side of the plant and constitute secondary cortex.
3. Phellogen is a few layers thick layer made of cork cambium.
4. Periblem us a meristematic tissue that gives rise to the cortex and is located in the cortical region of the root tip.

So the correct option is "Periderm".