Question

The function of cork cambium (phellogen) is to produce
A. Cork and secondary cortex
B. Secondary xylem and secondary phloem
C. Cork and secondary phloem
D. Secondary cortex and phloem

Answer 1

Hint: The root and stem of dicotyledonous flowering plants mostly develop periderm during secondary growth. Phellem of the periderm is composed of polygonal cells. Phelloderm is composed of living cells.

Complete step by step answer:
Secondary growth in dicotyledonous stem forms two types of tissues: vascular tissues and cork and phelloderm.
The true cambium present between xylem and phloem of the vascular bundles of the stem gives rise to secondary xylem and secondary phloem. The cells of the single layer of cambium divide and differentiate into the secondary vascular tissues. The cells that differentiate next to xylem form secondary xylem while the ones differentiated next to phloem develop into the phloem.
As the secondary tissues are formed, the pressure and overstretching kill the epidermal cells which are then replaced with periderm. Periderm consists of cork cambium or phellogen, cork, and the phelloderm. Phelloderm is also known as the secondary cortex while the cork is also called phellem.
Cork cambium is the meristematic part of the periderm. Its cells have tannins and chloroplasts. The meristematic cells of the cork cambium divide to form new cells on both sides. The cells formed on the outer side of the cork cambium constitute cork or phellem while the ones formed on the inner side make the secondary cortex.
So, the correct answer is option A. Cork and secondary cortex.

Note: Phellogen is formed in the outer layer of collenchyma tissue. The collenchyma cells become meristematic and divide to form the phellogen. Structurally, phellogen is composed of only a single type of cell.