MP Board · Class 10 · Science · How do Organisms Reproduce?Explain the process of sexual reproduction in flowering plants in detail. Describe the different parts of a flower and the events leading to fertilization and fruit formation.

Introduction to Sexual Reproduction in Flowering Plants\nSexual reproduction in flowering plants involves the production of male and female gametes, the transfer of male gametes to the female ovule, fertilization, and the subsequent development of seeds and fruits. Angiosperms are the flowering plants where the reproductive organs are located within the flower.

Parts of a Flower

• Sepals (Calyx): The outermost whorl of green leaf-like structures that protect the flower in the bud stage.
• Petals (Corolla): Usually brightly colored parts designed to attract pollinators like insects and birds.
• Stamen (Male Reproductive Organ): Consists of an anther (which produces pollen grains containing male gametes) and a filament (a stalk supporting the anther).
• Pistil or Carpel (Female Reproductive Organ): Consists of three parts:
  • Stigma: The sticky top surface that receives pollen grains.
  • Style: The tube-like structure connecting the stigma to the ovary.
  • Ovary: The swollen basal part containing ovules, which develop into seeds after fertilization.

Process of Fertilization

• Pollination: The transfer of pollen grains from the anther to the stigma of the same flower (self-pollination) or another flower (cross-pollination) by agents like wind, water, or insects.
• Germination of Pollen: Once the pollen lands on a compatible stigma, it germinates to form a pollen tube that grows down through the style into the ovary.
• Syngamy: The pollen tube releases male gametes into the ovule, where one male gamete fuses with the egg cell to form a zygote.

Post-Fertilization Changes

• The zygote divides multiple times to form an embryo inside the ovule.
• The ovule develops a tough coat and transforms into a seed.
• The ovary grows rapidly and ripens to form a fruit, while other floral parts like petals, sepals, and stamens usually wither and fall off.