The plant body consists of the root system, the shoot system and the leaf. Each of these parts of the plant body have their own characteristics and functions.

The Root System

The root is the non green, cylindrical part of the plant that normally grows under the ground into the soil. It develops from the radicle, which is the first structure that grows from a germinating seed. As the radicle grows it forms the primary root, which when continues to grow (as in dicotyledons) to form the main root of the plant which is called the Tap Root. On growing further, the tap root grows several lateral branches called the secondary roots, which in turn produce the tertiary roots. When the primary root is short-lived and is replaced by roots that arise from any other part of the plant body, then it is called adventitious roots. 

Characteristics of the Root

The main characteristics of the root of a flowering plant are as follows :

1. The root is the descending portion of the plant body.
2. It lacks chlorophyll containing cells.
3. It normally does not bear buds. Exceptions include sweet potato and wood apple roots which have buds that help in vegetative reproduction.
4. The root end is protected by a cap called as root cap.
5. The root bears unicellular root hairs which help in the absorption of water and mineral salts form the soil.
6. It is not differentiated into nodes and internodes.
7. It is positively geotropic.
8. Lateral roots always develop endogenously.

Functions of the Root

The root consists of several types of cells which carry out a variety of functions. Such as :

1. The root takes up water from the soil.
2. They absorb mineral salts from the soil, often against a concentration gradient.
3. It anchors and stabilizes the plant.
4. In some plants, the roots are modified to store food in the plant.
5. Sometimes, the roots are used for vegetative reproduction of the plant.

The Shoot System

The shoot is the ariel and erect part of the plant that usually grows above the ground. It develops from plumule and epicotyl of the embryo of the germinating plant.

Characteristics of the Shoot

The main characteristics of the shoot of a flowering plant are as follows :

1. The shoot is the ascending portion of the plant.
2. The young stem is green, as it contains chlorophyll,and thus photosynthesis occurs in it.
3. The stem bears both vegetative and floral buds. It end in a terminal bud.
4. It bears multi-cellular hairs on its surface.
5. It has distinct nodes and inter-nodes.
6. It is positively phototropic.
7. It bears the leaves, flowers and fruits.
8. The stem branches arise exogenously.

Functions of the Root

The shoot carries out a variety of functions. Such as :

1. It provides support for the main body of the plant.
2. It bears leaves in such positions that they can capture maximum sunlight.
3. It bears reproductive organs in such position that it aids in maximising pollination and seed dispersal.
4. It is flexible and is able to withstand the pulling and bending forces exerted by the wind.
5. It transports water, sugars and other dissolved substances to the various parts of the plant.
6. Sometimes the stem is modified for storing food.
7. In some plants the stem forms adventitious roots.
8. The stem is sometimes used as a means of plant reproduction.
9. In certain plants, like cactus, the stem forms the photosynthetic organ and also stores water.

The Leaf

The leaf is a flattened, lateral out growth of the stem. It develops from a node and has a bud in its axil. It is normally green in color and thus photosynthesis occurs in its cells. The leaves always develop in acropetal order.

Characteristics of the Leaf

1. Leaves are lateral out growth of the stem.
2. They arise at the nodes of the stem.
3. They are exogenous in origin and have limited growth.
4. They bear buds in their axils.

Functions of the Leaf

1. Leaves contain the photosynthetic pigment called chlorophyll. Thus it is involved in the reactions of photosynthesis.
2. They supply water and carbon dioxide to the site of photosynthesis.
3. They have a transport system (of veins) to remove the products of photosynthesis from the leaf.