Root

The root is the organ of a plant that typically lies below the

surface of the soil.

Root is the organ of the plant, originates from the radical of

the embryo.

The first root that comes from a plant is called the radicle.

It grows downwards, fixes the seedling later the plant to the

ground and absorbs raw food materials the soil

Characteristics

• Root does not normally bear buds.

• Root end is protected by a cup or thimble known as root cap.

• Root bears unicellular hairs, while the stem bears mostly

multicellular hairs.

• Nodes and internodes are absent in roots.

Functions

• Mechanical. eg. Anchorage• Physiological. eg.

• Absorption• Conduction• Storage mainly.

Types of Roots

• Normal Root

• Adventitious root / Fibrous root

Modifications of roots

Modified tap root

Fusiform rootSwollen in the middle and gradually tapering both ends. eg. Radish

Napiform rootThe upper part becomes almost spherical and sharply tapering at the bottom part. eg. Turnip.

Conical rootWhen the root is broad at the base and it gradually tapper towards the apex like a cone, it is said to be conical. eg. Carrot.

Tuberous rootWhen the root is thick and fleshy but does not maintain any particular shape, it is said to tuberous or tubercular. eg. Sweet potato

Modifications of rootsModified adventitious roots

Fasciculated root

When several tubercular roots occur in a cluster or fascicle at the base of

the stem are said to be fasciculate as in Dahlia and Asparagus

Moniliform root

When there are some swellings in root at frequent intervals, it is said to be

moniliform root. eg. Teasel gourd

Nodal root

When the slender root becomes suddenly swollen at or near the apex, it is

said to be nodal root. eg. Sugar cane

Epiphytic root

There are certain plants, commonly orchids, which grow on branches

of trees. Such plants are known as epiphytes.

In stead of sucking roots they develop special kinds of aerial roots

which freely in the air.

Each hanging root is surrounded by a spongy tissue, called velamen

with help of the velamen they absorbs moisture from the surrounding

air.

Modifications of roots