Question

Identify A to E in the given diagram.

• A. A-Endodermis, B-Pericycle, C-Protoxylem, D-Metaxylem, E-Pith
• B. A-Endodermis, B-Pericycle, C-Protoxylem, D-Pith, E-Metaxylem
• C. A-Endodermis, B-Pericycle, C-Pith, D-Protoxylem, E-Metaxylem
• D. A-Endodermis, B-Pith, C-Pericycle, D-Protoxylem, E-Metaxylem

Answer 1

The correct option is D A-Endodermis, B-Pith, C-Pericycle, D-Protoxylem, E-Metaxylem

The given diagram represents the transverse section of dicot root. The outermost layer is made up of the epidermis or epiblema. Interior to this lies the cortex which forms the major part of the root body and is composed of several layers of parenchyma cells. Next layer is the endodermis (A) which is a single layer of barrel-shaped cells with no intercellular spaces. Immediately below the endodermis lies the pericycle (C) composed of a single layer of thin-walled parenchymatous cells. The vascular bundles have a radial arrangement with xylem and phloem bundles arranged in a ring on alternate radii. The xylem bundles consist of protoxylem (D) which lies towards the periphery and metaxylem (E) which lies towards the centre of the root. This arrangement of xylem is known as exarch arrangement.
The pith (B) is small and inconspicuous. It is composed of parenchyma cells.