Parts of a Plant- Root, Stem, Leaves, Flower, Fruits
There are the main 5 parts of plants:
Roots are the underground part that holds the plant firmly in the soil and also absorbs water for the plant from the soil. Reserve food of root is starch.
Types of Roots
- Taproot, in which there is one main root and this gives out lateral branches. All dicot plant-like Mango, Nut, Pea, Gram are taproots.
- Fibrous roots, where there is no main root (spinach, moong), many roots seem to originate together from one point. All monocot plant-like Bajra, Rice, Wheat, etc are fibrous roots.
- Adventitious roots that come at different places in the plant other at the base of the stem.
There are xylem vessels and tracheids in roots and stems of plants that are just like pipes and help transport water and minerals from roots to stem to leaves, flower and fruits. There are some roots that store food also (carrots, radish and tapioca). Roots of some plants give rise to new plant (dahlia, sweet potato). Roots of the plant always move towards water and earth.
The stem of the plant is the main body that bears leaves, flowers, and fruits. Stem along with its branches held the leaves get maximum sunlight for use in photosynthesis. It carries water and minerals from the roots to leaves, flowers and fruits. The food prepared by the leaves is transported by the stem to all parts including roots. Extra food is sent to be stored to fruits, seeds sometimes roots and even in the stem (potato, sugarcane). So stem helps to transport water as well as food. The stem of a plant always moves towards the light.
- The stem is made by the Plumule part.
- The stem is an erect part.
- It gives support to plant.
- In stem, xylem and phloem are present.
- It helps in photosynthesis.
Types of Stem
- Strong Stem: Aerial stem is called strong stem. Example: Mango, Guava etc.
- Weak Stem: Feeble stem is called weak stem. The feeble stem is Sub-Aerial. Example: Cuscuta
- Underground Stem: Example: Stem of Potato and Banana.
Modified Stem: Those stems who modified for store food.
Example: Ginger, Potato, Turmeric, Garlic, Arvi, Canna, Saffron, Corm, etc.
Note: Potato is Modified Stem but “Sweet Potato” is modified root.
Leaves are the food factories of plants. They are of different shapes and size. Leaves are attached to the stem by a petiole. Some leaves don’t have petioles. They are called sessile.
Most of the leaves are green in colour as they have chloroplasts in their cells. Leaves have a number of veins running in their lamina that carry water for use in the process of photosynthesis.
The arrangement of the vein is of two types:
- Reticulate, in which there is one main vein called midrib and a number of lateral veins coming out of the midrib that forms a network and spread to each and every part of the leaf (mango, rose, neem, peepal)
- Parallel, in which vein runs parallel to each other (all grasses).
Some important point of Leaf
- The leaf of the plant is also known as the kitchen of the plant.
- The leaf is the main site for transpiration, photosynthesis, and respiration.
- The green colour of the leaf due to chlorophyll (plastid).
- Photosynthesis reaction of plant:
6CO2+12H2O → C6H12O6+6O2+6H2O
C6H12O6 + O2 → 6CO2+6H2O+ATP (energy)
It is defined as the process by which plants lose water in the vapour from the aerial parts of the plants.
Important of Transpiration
- Removal of Excess Water: Transpiration helps to remove excess water.
- Cooling Effect: Transpiration keeps regulating the temperature of the plant – since evaporation reduces temperature.
- Ascent of Sap: It is the upward movement of cell sap that is water and minerals through the xylem.
Flowers are the reproductive parts of the plant. Parts of a typical flower are sepals, petals, stamens and pistil.
Parts of Flower
- Receptacle: The base of the flower where its different parts are attached.
- Sepals: The green, leaf like outer parts of the flower. It covers and protects the bud till it blooms into a flower.
- Petal: The parts of a flower that are mostly bright in colour to attract the insects and birds for pollination.
- Stamen: The male reproductive organ of the flower. It has two parts:
Anther: The part of the stamen where pollens are produced.
Filament: A thin thread like structure that carries the anther.
- Pistil: The female reproductive organ of the flower. It has three parts:
Ovary: The swollen lower part of the pistil where ovules are produced. On maturity ovary becomes the fruit and ovules become the seeds.
Style: A long filamentous structure.
Stigma: The uppermost sweet and sticky part of the pistil. When pollens fall on it, they germinate. The male gamates move towards the ovary and fuse with the female gamete present in the ovule.
It is the process of transferring pollens from anther to stigma of pistil. This is done by air, water, bird, insects, or animals. Flowers pollinated by air and water don’t have bright colours or scent. Flowers pollinated by insects, birds, or animals are brightly coloured and have nectar in them. Flowers blooming in the night are generally white in colour and have pleasant scent.
If pollens of the same flower or same plant fall on the stigma, it is called self-pollination. If pollens of a different plant fall on the stigma, it is called cross pollination.
On the stigma pollens germinate and its pollen tube carrying male gametes grow out the style to the ovary. One of pollen tube reaches the ovary, gets inside the ovule and fuses with the female gamete. Zygote formed as a result of this fusion undergoes several divisions to form embryo.
It is the seed bearing structure formed from the ovary after flowering and ovule matures to form the seed.
The seed formed in the fruits come out in different ways and get dispersed by wind, water, birds, animals and human beings. In dicot seeds (gram, beans) food for the embryo is stored in the cotyledons. In monocots food is stored in the endosperm (wheat, maize).
Embryo in the seeds remain dormant till favourable condition for germination (air, water, temperature and light) are met. When everything is fine, the seed germinates to form a new plant.
Plants also reproduce by asexual reproduction like vegetative propagation, fragmentation, budding, spore formation, etc.