- A It replaces epidermis as plants grow older through activity of cork cambium (phellogen)
- B It is the original protective tissue covering young plants before any secondary growth begins
- C Periderm forms mainly within roots and is largely absent from stems
- D Periderm is generally another name used interchangeably for the original epidermis
Correct answer: A. It replaces epidermis as plants grow older through activity of cork cambium (phellogen)
Explanation: Periderm replaces the epidermis in mature woody stems and roots. It is produced by cork cambium (phellogen): outward divisions produce cork (phellem, dead cells with suberin), inward divisions produce phelloderm. Together: periderm = phellem + phellogen + phelloderm.
Concept context
Internal tissue organisation: meristems, permanent tissues (xylem, phloem, parenchyma), and secondary growth. Frequently tested in NEET.