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A Handbook of Biology

Morphology is the study of external forms of organisms.

A flowering plant (angiosperm) has 2 parts: Root system (underground part)

& Shoot system (portion above the ground).

THË RØØT

It is the underground part formed from radicle of embryo.

Root systems are of 3 types:

TAP ROOT SYSTEM

It consists of primary

roots (tap root) and its

branches (lateral roots

such as secondary

roots, tertiary roots).

Seen in dicots. Primary

root is elongated from

radicle. E.g. Mustard

plant.

ADVENTITIOUS

ROOT SYSTEM

Roots that arise from

parts other than

radicle. E.g. Grass,

Monstera and

Banyan tree.

1. RËGÏØÑS ØF RØØT

Root cap: It is the covering at

the apex of root. It protects

the tender apex of the root.

Region

of

meristematic

activity: Seen above the root

cap. Here, the cells are very

small, thin-walled and with

dense

protoplasm.

They

divide repeatedly.

Region of elongation: Region

just above the meristematic

region. Here, cells undergo

rapid elongation and enlargement. Helps in growth of the

root in length.

Region of maturation: It is proximal to elongation zone.

Here, the cells differentiate and mature.

2. MØDÏFÏÇÅTÏØÑS ØF RØØT

In some plants, roots are modified to perform functions

other than absorption and conduction.

Region of

Region of

elongation

Region of

meristematic

activity

Root cap

Root hair

maturation

FIBROUS ROOT

SYSTEM

In monocots, primary

root is short-lived and

is replaced by many

roots. They originate

from the base of stem

to form fibrous root

system. E.g. Wheat.