Ch – 12 Reproduction In Plants

  • The production of new individuals from their parents is known as reproduction.
  • Roots, stem and leaves are known as the vegetative parts of a plant.
  • Flowers are the reproductive part of the plant.
  • The two categories of reproduction are: sexual reproduction and asexual reproduction.
  • 1) Asexual Reproduction
  • The reproduction where plants can reproduce new plants without seeds is known as asexual reproduction.
  • Types of asexual reproduction are:
  • Vegetative Propagation
  • New plants are produced from roots, stems, leaves and buds.
  • Eg: Rose plant and money plant can be reproduced by cutting its stem, Bryophyllum has buds in the leaf margin which gives rise to new plants, Sweet potato and dahlia reproduce through roots.
  • Plants produced by vegetative propagation take less time to grow and bear flowers and fruits earlier than those produced from seeds.
  • The new plants are exact copies of the parent plant, as they are produced from a single parent.
  • Budding
  • In this process, bud forms and gets detached from parent cell. Later, it grows into a new cell.
  • Eg: Yeast, Bacteria, Hydra, Coral.
  • Fragmentation
  • In this process, the organism splits into fragments and each fragment grows into a new organism.
  • Eg: Algae, Spirogyra, Sponges, Lichens.
  • Spore Formation
  • Each spore is covered by a hard protective coat to withstand unfavourable conditions such as high temperature and low humidity.
  • Under favourable conditions, a spore germinates and develops into a new individual.
  • Eg: Fungi, Moss, Fern.
  • 2) Sexual Reproduction
  • The reproduction where plants can reproduce new plants with seeds is known as sexual reproduction.
  • Stamen is the male reproduction part and Pistil is the female reproductive part of a plant.
  • The flowers which contain either only the pistil or only the stamens are called unisexual flowers. Eg: Corn, Papaya.
  • The flowers which contain both stamens and pistil are called bisexual flowers. Eg: Rose, Petunia.
  • 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 egg is 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. Wind, water and insects are agents of pollination.
  • If the pollen lands on the stigma of the same flower it is called self-pollination. Eg: Orchids, Pea.
  • 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. Eg: Grasses, Daffodils.
  • 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.
  • After fertilisation, the ovary grows into a fruit and other parts of the flower fall off.
  • The fruit is the ripened ovary.
  • The seeds develop from the ovules.
  • The seed contains an embryo enclosed in a protective seed coat.
  • Seeds are carried away from their parent plant. It is known as dispersal of seeds.
  • The agents of seed dispersal are wind ( Drumstick, Maple ), water ( Coconut, Mangroves ), animals ( Xanthium, Urena ) and explosion ( Castor, balsam ).
  • The dispersal of seeds is important because:
  • Prevents competition for sunlight, water and minerals.
  • Helps in invading new habitats.

Published by Priya Prakash

In the midst of winter, i found there was within me an invincible summer ~ Albert Camus

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