Question

Read the following statements about the vascular bundles :

(a) In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii.

(b) Conjoint closed vascular bundles do not possess cambium

(c) In open vascular bundles, cambium is present in between xylem and phloem

(d) The vascular bundles of dicotyledonous stem possess endarch protoxylem

(e) In monocotyledonous root, usually there are more than six xylem bundles present

Choose the correct answer from the options given below

Answer 1

Within a vascular bundle, when xylem and phloem are arranged in an alternate manner on different radii, the arrangement is called as 'radial'. Such, arrangement is present in root.

In monocot stem vascular bundles are conjoint and closed (without cambium).

Open vascular bundles have cambium and the possibility of further xylem and phloem.

Endarch is used when there is more than one strand of primary xylem in a stem or root and the xylem develops from the inside outwards towards the periphery, i.e., centrifugally. The protoxylem is thus closest to the center of the stem or root and the metaxylem closest to the periphery. The stems of monocots typically have endarch development.

Vascular bundles in monocot roots are radial, polyarch and exarch. Large number (more than 6) of xylem and phloem groups alternate with each other. A well developed pith is present in monocot root.