Reproduction in Plants

Introduction

• Plants reproduce to generate offspring.
• The process of reproduction is called pollination.
• Flowers contain male and female sex parts.
  • Male: Stamen (contains pollen in anther)
  • Female: Pistils (consists of ovary, style, stigma)
• Modes of pollination include wind and water, leading to seeds and fruits.

Types of Reproduction

1. Sexual Reproduction

   • Involves fusion of gametes to produce offspring.
   • Leads to evolution and variations; offspring differ from parental plant.

   Process of Sexual Reproduction

   • Occurs in the flower.
   • Key phases: Meiosis, Pollination, and Fertilization.
   • Post-fertilization, flowers turn into fruits.

   Reproductive Parts of a Flower

   1. Calyx/Sepals: Green leaflets that protect the flower bud.
   2. Corolla/Petals: Colorful, attract insects for pollination.
   3. Androecium/Stamen: Male reproductive organ; holds pollen.
   4. Gynoecium/Pistil: Female reproductive organ; includes ovary, style, stigma.

   Types of Flowers

   • Bisexual Flowers: Both stamen and pistil in one flower (e.g., rose, hibiscus).
   • Unisexual Flowers: Only one reproductive organ present (e.g., papaya, maize).

   Pollination

   • Process of pollen transfer from anther to stigma.
   • Self-Pollination: Pollen from same plant lands on its own stigma.
   • Cross-Pollination: Pollen transferred to different flower.

   Agents of Pollination

   • Wind, Water, Insects, Birds
   • Examples:
     • Wind: Rice, maize
     • Water: Aquatic plants like coconut
     • Insects: Attracted by bright colors and nectar.

2. Asexual Reproduction

   • Involves only one parent.

   Different Modes of Asexual Reproduction

   • Vegetative Propagation: Root, Stem, Leaves
   • Budding
   • Fragmentation
   • Spore Formation

   Types of Asexual Reproduction

   • Natural Methods: Budding, Vegetative propagation, Fragmentation, Spore formation
   • Artificial Methods: Cutting, Grafting, Layering, Micropropagation

   Natural Methods

   • Budding: Bud formation at specific sites (e.g., potato)
   • Vegetative Propagation:
     • Root: Tuber forms new plant (e.g., sweet potato).
     • Stem: New buds at nodes grow into plants.
     • Leaves: Detached leaves can grow new plants (e.g., Bryophyllum).
   • Fragmentation: New plants from stem/root fragments (e.g., Spirogyra).
   • Spore Formation: Spores withstand harsh conditions; seen in fungi, mosses.

Conclusion

• Reproduction in plants involves both sexual and asexual methods.
• Pollination involves agents like wind, water, and animals.
• Natural and artificial methods facilitate asexual reproduction.