Page 2 - Lesson Notes-Morphologyof flowering plant

lies partly within and partly beyond the root cap. Its cell divide regularly and
repeatedly for elongation. It is responsible for the growth of the root.

iii. Zone of Elongation
It is situated behind the meristematic region (growing point). The cells elongate
speedily and increases the length of the root. The cells of this region can absorb
water and minerals from the soil.
iv. Root Hair Zone
It is the region where primary tissues differentiate into the root. The vascular tissues
like xylem and phloem are formed.
Root hair zone is the most important part of the root for absorption of water (most of
the water) from the soil. The root hairs increase the exposed surface of the root for
absorption.
v. Zone of Maturation
This zone contains mature cells. It forms the permanent zone of the root and also
gives out lateral roots from the interior part of this region, e.g., In dicots and
gymnosperms.
• Roots of parasitic plants lack root caps.
• In aquatic plants, root hairs are usually absent.
Types of Root System
The root system can be of two types on the basis of place of origin
i. Tap Root System
The tap root develops from the radicle of embryo of a seed. In most of the plants,
primary root persists and becomes stronger to form tap root. The first root forms by
the elongation of radicle and is called primary root. It continuously grows and
produces lateral roots called secondary roots.
The further branches of the secondary roots are called tertiary roots and so on.
These types of roots are present in dicots, e.g., Pea, gram, groundnut, etc.
ii. Adventitious Root System