Plant Parts

In human beings and animals, major functions of the body are carried out by tissues and organs. Similarly, plants also have specialized tissues and structures to carry out functions. The tissues and structures make up two broad systems: the shoot system and the root system. The shoot system is made up mainly of leaves, stems, and reproductive structures, for example, flowers, fruit, seeds, etc. and the root system is made up of roots. Each of these structures has properties that help it to carry out its major function. The main parts of plants are the root, stem, flower and leaves of plants. The descriptions of plant parts and functions are explained below.

Root

The roots are the parts of plants that form their foundation in the soil. In the maximum number of the dicotyledonous plants, the direct elongation of the radicle leads to the formation of a primary root that grows inside the soil. It contains lateral roots of several orders that are referred to as secondary, tertiary, etc., roots. The primary roots and their branches constitute the tap root system, as seen in the mustard plant. In monocotyledonous plants, the primary root is short-lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system, as seen in the wheat plant. In some plants, like grass, monstera and the banyan tree, roots arise from parts of the plant other than the radicle and are called adventitious roots. The main functions of the root system are absorption of water and minerals from the soil, providing a proper anchorage to the plant parts, storing reserve food material and synthesis of plant growth regulators.

Stem

The stems are the ascending parts of plants. They contain branches, leaves, flowers and fruits. The stem develops from the plumule of the embryo of a germinating seed. There are nodes and internodes present on the stem. Nodes are the region of the stem where leaves are formed, while internodes are the portions between two nodes. The stem bears buds, which may be terminal or axillary. The stem is generally green when young and later often becomes woody and dark brown. The main function of the stem is spreading out branches bearing leaves, flowers and fruits. It transfers water, minerals and photosynthates. Some stems also perform the function of storage of food, support, protection and vegetative propagation. 

Leaf

The leaves of plants are lateral, generally flattened structures borne on the stem. They develop at the node and bear a bud in the axil. The axillary bud later develops into a branch. Leaves are produced from shoot apical meristems and are arranged in an acropetal order. A leaf consists of three main parts: leaf base, petiole and lamina. The leaf is attached to the stem by the leaf base and may bear two lateral small leaf-like structures called stipules. In monocotyledons, the leaf base expands into a sheath covering the stem partially or wholly. In some leguminous plants, the leaf base may become swollen, which is called the pulvinus. The petiole helps hold the blade to light. Long thin, flexible petioles allow leaf blades to flutter in the wind, thereby cooling the leaf and bringing fresh air to the leaf surface. The lamina of the leaf blade is the green expanded part of the leaf with veins and veinlets. There is usually a prominent middle vein, known as the midrib. Veins provide rigidity to the leaf blade and act as channels of transport for water, minerals and food materials. The main function of a leaf is to produce food for the plant by photosynthesis. Chlorophyll, the substance that gives plants their characteristic green colour, absorbs light energy.

Flower

Flowers are the parts of plants that are reproductive. They are found in the type of plants called angiosperms. It is meant for sexual reproduction. A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called the thalamus or receptacle. These are calyx, corolla, androecium and gynoecium. Calyx and corolla are accessory organs, while androecium and gynoecium are reproductive organs. In some flowers like lilies, the calyx and corolla are not distinct and are termed perianth. When a flower has both androecium and gynoecium, it is bisexual. A flower having either only stamens or only carpels is unisexual.

Conclusion:

Plants have specialized tissues and structures to carry out functions. The tissues and structures make up two broad systems: the shoot system and the root system. The major parts of plants are the root, stem, flower and leaves. The roots perform absorption of water and minerals from the soil, provide proper anchorage and store reserve food material. Stem transfers water, minerals and photosynthates. Some stems also perform the function of storage of food, support, protection and vegetative propagation. The main function of a leaf is to produce food for the plant by photosynthesis. Flowers are the reproductive parts of the plant responsible for sexual reproduction.