Structures and Functions of the Living Body
All animals and plants have different organs to perform various functions. Each part of the body of an animal or plant is different in structure. The organs, however, function in coordination with one another.
SPECIFIC PARTS OF PLANTS
- Plants have two main systems: (i) the root system (ii) the shoot system
The Root System
The root system grows mainly underground. Root systems are of two types:
(i) Tap root system
(ii) Fibrous root system
(i) Tap root system: It is a main root and grows vertically down into the soil. The tap root gives out branches. For example, pea, neem, mango.
(ii) Fibrous root system: Some plants do not have main root. They have many fibre-like roots. These are called fibrous roots. These roots spread out in the soil and give firm support to the plant. For example, wheat, grass, maize and millet.
Advantages of the root system: As roots grow normally underground, they fix the plant to the ground. They absorb the mineral salts and water from the ground, which are needed for the plant to grow. Roots also help hold the soil together. They save the soil from being blown off or washed away.
The Shoot System
The shoot system grows above the ground. It consists of the main stem, its branches and leaves.
(i) The stem: The stem holds the plant upright. The stem is the strongest part of a tree and is known as the trunk. Most trunks are observed with bark. The bark protects the inner part of the tree. The stems-of some plants are weak. They cannot stand erect.
Stems carry water from the roots to the leaves and flowers. They also carry food from the leaves to other parts of the plant. They hold the leaves in such a way that the leaves get plenty of light from the sun.
(ii) The leaves: Leaves are important parts of plants. They manufacture food for the plants. They are green because they contain a green pigment. This pigment is called chlorophyll. To manufacture food, the green leaves need sunlight, air and water. The process of making food in the presence of sunlight is called photosynthesis.
(iii) Flowers and fruits: In a flower, the green leaf-like parts in the outermost circle are called sepals. Towards the centre of a flower many little stalks with swollen tops are present and they called stamens. The swollen tops are called anthers. They contain a powdery substance called pollen. The stamen is the male part of a flower. In the centre of the flower, there is a flesh-shaped organ called the carpel. The carpel is the female part of a flower. The little swollen portion at the base is called the ovary. The ovary contains egg-like structures called ovules. Pollen are transferred to the carpel in a process called pollination. This is done by insects, wind and water. Eventually, the ovules of the flower turn into
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