Question

Normally in dicot stems, phellogen develops from

• A. Hypodermis
• B. Phellem
• C. Endodermal cells
• D. Epidermal and pericycle cells

Answer 1

The correct option is A Hypodermis

Phellogen is the extrastelar lateral meristem that produces extrasteler secondary tissue system. Epidermis is the outermost covering of the primary stem that delimits cotex on outer side and is ruptured by stelar secondary growth, therefore cannot produce phellogen. Cortex is the ground tissue which surrounds the central stele and is derived from ground meristem. Hypodermis refers to 5-7 layers of cortical cells present just beneath the epidermis which resume the meristematic activity and produce phellogen just beneath the epidermis. The innermost layer of cortex forms endodermis while the phellogen is produced just beneath the epidermis. The outermost covering of stele forms pericycle it is an intrasteler tissues present in a stele which means that phellogen (extrastelar lateral meristem) cannot be produced by pericycle. The phellogen or cork cambium produces cork or phellem towards the periphery.
Therefore, the correct answer is option A.