Question

In dicot stem, cork cambium first derived from
A.Cortex
B.Phellogen
C.Phelloderm
D.Pericycle

Answer 1

Hint: Cork cambium or phellogen develops from the outer layer of cortex that help to produce a secondary cortex known as phelloderm on the inner side and on the outer side it forms a cork or phellem.

Complete step by step answer:
-Cork cambium can be described as the extra stelar lateral meristem that produces extra stelar secondary tissue systems.
-Cortex is the ground tissue which surrounds the central stele and is a result of ground meristem.
-Hypodermis refers to the 5-7 layers of cortical cells that are present just beneath the epidermis which restart the meristematic activity. It also helps to yield the phellogen or cork cambium just beneath the epidermis.
-The outermost covering of stele forms a pericycle that is an intra stelar tissue present during a stele formation which suggests that phellogen, which is called extra stelar lateral meristem, cannot be produced by pericycle.
-Phellem and phelloderm are the product of cork cambium but not its progenitor.
-The Cork cambium may be a lateral meristematic tissue that is found in vascular plants. It is a component of the periderm. This forms in living cells of the epidermis, cortex, and in some plants, it forms phloem.
-The cork cambium which produces a secondary protective tissue called the periderm is liable for the secondary growth in many woody and herbaceous dicots, gymnosperms and a few monocots and replaces the epidermis in roots and stems.

Thus, the correct answer is option A. cortex.

Note:
Secondary growth of plants occurs in the cortex of the dicot stem. This process is called extra stelar secondary growth. It includes the formation of a ring of meristematic tissue – known as cork cambium or phellogen. It is formed by the dedifferentiation of collenchyma cells that are present in the cortex region. It undergoes periclinal cell divisions that help to produce outer and inner cells. The outer cells form the cork or phellem and the inner cells form the secondary cortex or phelloderm. Cork, cork cambium and secondary cortex all together is known as Periderm.