Question

Periderm includes
(a) Phellem
(b) Phelloderm
(c) Phellogen
(d) Phellem, Phelloderm, and Phellogen

Answer 1

Hint: It is a cylindrical tissue that covers the surfaces of stems and roots of perennial plants during early secondary growth; therefore it is not found in monocots and is bound to those gymnosperms and eudicots that show secondary development.

Complete answer
During development in the thickness of stems and establishment of gymnosperms and dicotyledons (i.e., secondary development) the periderm is the secondary defensive dermal tissue that replaces the epidermis. In contrast to the standard epidermis, the periderm might be a multilayered tissue framework, most of which generally establishes the cork or phellem, phellogen or cork cambium, and phelloderm.

Additional information
The term periderm etymologically means “about, around” (from the Greek peri) and “skin” (from the Greek derma). Along these lines, it largely relates to an external defensive layer. The term periderm is the external covering of specific plants, particularly woody plants in botany. It is the outermost layer of the bark made from cork cells, cork cambium, and phelloderm. The epidermis of the stems and woody plants will be replaced. It is more effective for preventing water loss and is more resistant to mechanical injuries. Due to this, the cork cells are situated at the outermost. These cells are dead cells impregnated with materials such as tannins and suberin. The cork cells originate from the cork cambium and it is the meristematic part of the periderm.
Aside from the cork cells, the cork cambium likewise gives new cells that structure the inward layer of the periderm, phelloderm.

So the correct answer is ‘Phellem, Phelloderm, and Phellogen’.

Note:
The term periderm is also used in embryology and zoology. In embryology, it relates to the farthest layer of specific embryos and fetuses at the 6th month gestational age. This layer, likewise called epitrichium, typically vanishes before birth. In zoology, another term for perisarc is the periderm, which is defined as the outer hard covering in the case of many hydroids.