NCERT Gist: Reproduction In Plants | Additional Study Material for UPSC PDF Download

- The production of new individuals from their parents is known as reproduction.
- Most plants have roots, stems and leaves. These are called the vegetative parts of a plant.
- The flowers perform the function of reproduction in plants.
- Flowers are the reproductive parts of a plant. There are several ways by which plants produce their offspring. These are categorised into two types: (i) asexual, and (ii) sexual reproduction. In asexual reproduction plants can give rise to new plants without seeds, whereas in sexual reproduction, new plants are obtained from seeds.
- In asexual reproduction new plants are obtained without production of seeds or spores

Vegetative Propogation

- It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation.
- Apart from flower buds, there are buds in the axil (point of attachment of the leaf at the node) of leaves which develop into shoots.
- These buds are called vegetative buds.
- A bud consists of a short stem around which immature overlapping leaves are folded.
- The vegetative buds can also give rise to new plants.
- Bryophyllum (sprout leaf plant) has buds in the margins of leaves.
- If a leaf of this plant falls on a moist soil, each bud can give rise to a new plant.
- Plants produced by vegetative propagation take less time to grow and bear flowers and fruits earlier than those produced from seeds.
- The small bulb-like projection coming out from the yeast cell is called a bud.
- The bud gradually grows and gets detached from the parent cell and forms a new yeast cell.
- The new yeast cell grows, matures and produces more yeast cells.
- Sometimes, another bud arises from the bud forming a chain of buds.
- If this process continues, a large number of yeast cells are produced in a short time.
- Slimy green patches in ponds, or in other stagnant water bodies. These are the algae.
- When water and nutrients are available algae grow and multiply rapidly by fragmentation. An alga breaks up into two or more fragments.
- The fungi on a bread piece grow from spores which are present in the air. When spores are released they keep floating in the air.
- As they are very light they can cover long distances.
- The spores are asexual reproductive bodies.
- Each spore is covered by a hard protective coat to withstand unfavourable conditions such as high temperature and low humidity and can survive for a long time.
- Under favorable conditions, a spore germinates and develops into a new individual. Plants such as moss and ferns also reproduce by means of spores.
- The flowers which contain either only the pistil or only the stamens are called unisexual flowers.
- The flowers which contain both stamens and pistil are called bisexual flowers.
- Corn, papaya and cucumber produce unisexual flowers, whereas mustard, rose and petunia have bisexual flowers. Anther contains pollen grains which produce male gametes.
- A pistil consists of stigma, style and ovary.
- The ovary contains one or more ovules. The female gamete or the eggis formed in an ovule.
- In sexual reproduction a male and a female gamete fuse to form a zygote. The transfer of pollen from the anther to the stigma of a flower is called pollination.
- If the pollen lands on the stigma of the same flower it is called self-pollination. When the pollen of a flower lands on the stigma of another flower of the same plant, or that of a different plant of the same kind, it is called cross-pollination. The cell which results after fusion of the gametes is called a zygote.
- The process of fusion of male and female gametes (to form a zygote) is called fertilisation.
- The zygote develops into an embryo.
- All organisms multiply or reproduce their own kind. In plants there are two modes of reproduction, asexual and sexual.
- There are several methods of asexual reproduction such as fragmentation, budding, spore formation and vegetative propagation.
- Sexual reproduction involves the fusion of male and female gametes.
- In vegetative propagation new plants are produced from different vegetative parts such as leaves, stems and roots.
- Flower is the reproductive part of a plant.
- A flower may be unisexual with either the male or the female reproductive parts.
- A bisexual flower has both the male and the female reproductive parts.
- The male gametes are found inside the pollen grains and female gametes are found in the ovule.
- Pollination is the process of transfer of pollen grains from the anther of one flower to the stigma of the same or another flower.
- Pollination is of two types, self-pollination and cross-pollination.
- In self-pollination, pollen grains are transferred from the anther to the stigma of the same flower.
- In cross-pollination, pollen grains are transferred from the anther of one flower to the stigma of another flower of the same kind.
- Pollination takes place in plants with the help of wind, water and insects.
- The fusion of male and female gametes is called fertilisation.
- Fertilised egg is called zygote.
- Zygote develops into an embryo. Fruit is the mature ovary whereas ovule develops into a seed, which contains the developing embryo. Seed dispersal is aided by wind, water and animals.
- Seed dispersal helps the plants to (i) prevent overcrowding, (ii) avoid competition for sunlight, water and minerals and (iii) invade new habitats.