Topic outline

    • Parts of a plant

      We depend on nature for all our basic need. Plants are one of big groups of nature. They are autotrophic which means they can make their own food. We obtain many things from plants such as cereals, pulses, vegetables, fruits, wood, fibre, rubber, gum, tea, coffee etc.

      Plants includes trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants is known as botany. Fungi and non-green algae are not considered as plants. Basic parts of plants are roots, stems, leaves, flowers, fruits, and seeds. Each part of a plant has a very important function. 


      The Root System- Root is the underground part of the plants body and grows towards the force of gravity. It fixes the plant within the soil and absorbs water and mineral nutrients from the soil. It stores excess food.

      Tap Roots- It consists of one main root growing downwards from which lateral roots develop which may initially grow horizontally then turn downward. Taproots are also important adaptations for searching for water and minerals from deep within the soil.

      Examples: sugar beet or carrot etc.

      Fibrous Roots- It consists of a dense mass of slender roots that arise from the stem. The roots grow downward and outward from the stem, branching repeatedly to form a mass of fine roots.

      Example: lilies, grasses, palm etc.


      In some plants the roots are modified to do special tasks. They are called Modified Roots.

      Some of them are:-

      Storage roots- These consist of a thickened roots due to the accumulation of high-energy storage compounds, usually starch.

      Example: carrot, sweet potato, cassava, raddish etc.

      Aerial roots- These fibrous roots remain aerial, i.e. they do not enter the soil. It performs special functions such as water retention, photosynthesis, and support.

      Example: Old banyan trees have aerial roots hanging down. It provides support to the tree.

      Aquatic Roots - These are specialized roots in some plants that grow in watery places and which function mainly for water and nutrient absorption. Its root system consists of long fibrous roots.

      Example: water lily


      The Shoot System- It is the aerial part of the plant body and enables a plant to grow taller to gain access to energy-giving light, and helps plant to prepare food. It is composed of erect stems on which are attached leaves, flowers, branches and buds. Leaves are attached to the stem at regions called nodes.

      Stem- It supports the upper parts of plants. It carries the water and nutrients needed for plants to grow from roots to leaves and food produced by the leaves to other part of plants. Stems also store food for the plant.

      Typical stems are located above ground, but there are modified stems that can be found either above or below ground.

      Tendrils-In various climbing plants, such as the grapes, some parts of stems are modified into coil like structures called tendrils. They are weak, so they take the support of other structures to help the plants to climb up and grow.

      Runners or stolons - Stems that grow in a creeping fashion horizontally above the surface of the soil are called runners, or stolons. Nodes of these stem if touches soil, give rise to new plant. Example –water melon, pumpkin etc.

      Water storing stem-Some cacti and a few other kinds of plants have stems that look like leaves. They are green and thus manufacture and store food.

      Underground modified stem- potato, garlic, onion and ginger are example of underground stem.


      Leaves -These are the parts of the plant where food is made by the process of photosynthesis. That’s why leaves are called the food making factories of green plants. Chlorophyll (green pigment) present in the leaves uses the energy in sunlight to turn water (H2O) and carbon dioxide gas (CO2) into sugar and oxygen gas (O2). Leaves are of different shapes and sizes.  The outer surface of the leaf has a waxy coating which protects the leaf. The flat surface of the leaf is called leaf blade or lamina. It has veins running across within the leaf. Tiny opening on the surface of the leaves called stomata helps in the exchange of gases.

      Parts of leaf

      Modified Leaves

      Spines-leaves are modified as spines in cactus for protection. Due to the scarcity of water in desert, in some plants leaves are modified to form spines.

      Tendrils-They are spring like structure that is coiled spirally. They are leaves modified for support and when they come in contact with any structure, they coil around that support. Example:-pea

      In plants like onion, the leaves are modified as storage organs. These leaves protect stem at the base of the onion. Example: Onions.

      Needle Leaves-The most modification in leaves is related to the need of water by the plant. Needle like leaf modification is seen in plants like pines, firs etc.

      Venus fly trap plants are designed to capture and digest insects between the folds of their specialized leaves.

      Bougainvillea is a plant with flower-like spring leaves near its flowers.


      Flowers: Flowers are the most attractive part of a plant. Each flower types have a different physical structure, color and scent from those of other flower type plants. Petals and the flowers smell attract insects and bees to pollinate the flower.  After pollination, the petals fall off and seeds develop in the part of a flower called the ovary.  The ovary itself usually becomes the fruit.

      Pollination is the process by which pollen is transferred from the anther to the stigma of the plant. Some of the agents of pollination are insects, wind, birds, mammals, water.

      Parts of flower

      Petals - The parts of a flower that are often brightly colored or unusually shaped to attract pollinators. They are the most attractive part of the plant.

      Sepals –These are small and green in color composing the outermost part of a flower. It encloses and protects the bud and may remain after the fruit forms.

      Pistils - The pistil usually is based in the center of the flower and is consist of three parts: the stigma, style, and ovary.

            1.   Stigma - It is the waxy, sticky bulb in the center of flowers and is the part which receives pollen.

            2.   Style - It is a long, slender stalk that connects the stigma and the ovary.

            3.   Ovary- The ovary is located at the bottom of the style

            4.   Stamen - It is the pollen-producing part of a flower is consist of two parts: Anthers and Filament

                          i.        Anthers – It is pollen producing structure. These are generally yellow in color.

                         ii.        Filament – It is a thread like structure which holds anthers.


      Fruit and Seed

      The fruit is a fleshy or dry ripened (mature) ovary of a plant, enclosing the seed or seeds. Most plants grow from seeds. A seed (mature ovule) is a miniature plant with a protective outer covering called the seed coat, usually with some stored food. Seeds are dispersed either by wind, water or animals. On getting air, water and sunlight, seed grow into baby plant. Most plants grow in the ground, with stems above, and roots below.


      Dispersal of seeds

      Seeds dispersal means movement of seeds from parent plant to another place. Dispersal of seeds is stops overcrowding and to create new colonies.

      By Wind

      Some seeds are scattered by wind  are usually enclosed in wing-like husks or fluffy coverings that help them to fly away long distance from the parent plant. For example, Dandelion seeds develop very light and fluffy parachute-like structures. These help the seeds to float in the wind and delay their fall to the ground.

      By Water

      Aquatic plant and plants that grow beside water have buoyant, waterproof coverings that allow them to float and disperse their seeds by water. Fruits which float such as those of the water lily and the coconut palm are carried by water and can travel for long distance.

      By Animal and Humans

      Seeds with sticky hairs, bristles, hook, or barbs are transported by sticking to the fur of animals or on the clothing of human beings and are carried long distance. Birds and other animals eat the fleshy fruits and discard the seeds or they may eat both but the seeds are not digested and are passed out as waste, and are ready to grow.

      By Explosion of fruit

      Some plants distribute their seeds by ejecting them with force when they are dried in the sun so that they fall well away from the parent plant. This is explosive dispersal. An example of this is plants which belong to the Pea Family .They produce seed pods which dry in the sun and suddenly split into two halves and disperse their seed.

      Reproduction without seeds

      Reproduction is the production of new individuals or offspring in plants. Not all new plant grows from a seed. There are some plants that employ vegetative propagation and grow new plants. Vegetative propagation is a process by which new organisms arise without production of seeds or spores. In this process only one plant is involved and the offspring (new plant) is genetically identical to the parent. New plants grow from parts of the parent plant.

      Many parts of plant are used for the asexual reproduction

      Stems- Aerial weak stems when touches the ground, give of adventitious roots and if it detach from the parent plant, newly formed roots develops into an independent plant ex- strawberry, grass. Other examples of stem propagation are ginger, banana, turmeric etc.

      Leaves-In some plant, buds develops on leaf margins. These buds remain dormant till leaf remain attached with plant but develop into new plant when fall off from the plant and come in the contact of soil. Ex -Bryophyllum

      Roots- The roots of some plants develop adventitious buds on them. Example: guava, dahlia & sweet potato. These buds sprout under suitable conditions and when detached from the parent plant turns into new plant.

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