Reproduction in Plants

Modes of Reproduction

Introduction

• Reproduction: Production of new individuals from their parents.
• Importance: Characteristic of all living organisms.
• Modes of Reproduction: Asexual and Sexual.

Modes of Reproduction

• Vegetative Parts of Plants: Roots, stems, leaves.
• Reproductive Part: Flowers, which lead to fruit and seeds.

Types of Reproduction

1. Asexual Reproduction: New plants from parts other than seeds.
2. Sexual Reproduction: New plants from seeds.

Asexual Reproduction

• Vegetative Propagation: New plants from roots, stems, leaves, and buds.

Examples and Activities

1. Rose/Champa Cutting:
   • Cut a branch with a node.
   • Bury in soil and water daily.
   • Observe roots and new leaves.
2. Money Plant:
   • Grow in water.
   • Observe growth.
3. Potato:
   • Observe “eyes” (buds).
   • Cut into pieces with eyes.
   • Bury in soil and water.
   • Observe growth.
4. Ginger/Turmeric:
   • Can also grow from pieces with buds.
5. Bryophyllum:
   • Buds on leaf margins.
   • Each bud can grow into a new plant.
6. Sweet Potato/Dahlia:
   • Roots can give rise to new plants.
7. Cacti:
   • Detached parts can grow into new plants.

Advantages of Vegetative Propagation

• Faster growth.
• Early flowering and fruiting.
• Exact copies of the parent plant.

Conclusion

• Sexual Reproduction: Produces seeds with characters of both parents.
• Vegetative Propagation: Efficient and quick method for reproducing plants.

Budding

• Yeast: Single-celled organism, seen under a microscope.
• Reproduction: Multiplies rapidly with sufficient nutrients.

Fragmentation

• Algae: Slimy green patches in ponds/stagnant water.
• Reproduction:
  • Alga breaks into fragments.
  • Each fragment grows into a new individual.
  • Rapidly covers large areas.

Spore Formation

• Fungi (Example: Bread Mold):
  • Grows from spores in the air.
  • Spores are light and can travel long distances.
• Spores:
  • Asexual reproductive bodies.
  • Hard protective coat to survive harsh conditions.
  • Germinate under favorable conditions.
• Plants: Moss and ferns also reproduce by spores.

Sexual Reproduction in Plants

Structure of a Flower

• Reproductive Parts:
  • Stamens: Male part.
  • Pistil: Female part.

Parts of Reproductive Organs

• Stamen:
  • Anther: Contains pollen grains (male gametes).
  • Filament
• Pistil:
  • Stigma, Style, Ovary
  • Ovules: Contain female gametes (eggs).

Pollination

• Process: Transfer of pollen from anther to stigma.
• Self-Pollination: Pollen lands on the stigma of the same flower/plant.
• Cross-Pollination: Pollen lands on the stigma of a flower on a different plant.

Fertilization

• Fusion of Gametes: Male and female gametes form a zygote.
• Zygote: Develops into an embryo.

Fruits and Seed Formation

• Post-Fertilization: Ovary becomes a fruit; ovules become seeds.
• Types of Fruits:
  • Fleshy and Juicy: Mango, orange.
  • Hard: Almonds, walnuts.

Seed Dispersal

• Importance: Prevents competition, enables wider distribution.
• Methods:
  • Wind: Winged or light seeds (e.g., drumstick, maple, grasses).
  • Water: Seeds with floating ability (e.g., coconut).
  • Animals: Spiny seeds with hooks (e.g., Xanthium, Urena).
  • Bursting Fruits: Seeds scattered by sudden jerks (e.g., castor, balsam).

Summary

• Sexual Reproduction: Involves male and female gametes.
• Pollination and Fertilization: Lead to fruit and seed formation.
• Seed Dispersal: Ensures plant survival and spread.

Chapter Summary:

• All organisms reproduce their own kind.
• In plants, there are two modes of reproduction: asexual and sexual.
• Asexual reproduction methods include fragmentation, budding, spore formation, and vegetative propagation.
• Sexual reproduction involves the fusion of male and female gametes.
• Vegetative propagation produces new plants from leaves, stems, and roots.
• The flower is the reproductive part of a plant.
• Flowers may be unisexual or bisexual.
• Male gametes are found in pollen grains, and female gametes are found in the ovule.
• Pollination is the transfer of pollen grains from one flower’s anther to another flower’s stigma.
• Types of pollination: self-pollination and cross-pollination.
• Pollination occurs with the help of wind, water, and insects.
• Fusion of male and female gametes is fertilization.
• The fertilized egg is called a zygote, which develops into an embryo.
• Fruit is the mature ovary, while the ovule develops into a seed containing the embryo.
• Seed dispersal is aided by wind, water, and animals.
• Seed dispersal helps prevent overcrowding, competition for resources, and enables plants to invade new habitats.

Keywords

Serial No.	Keywords	Serial No.	Keywords
1	Asexual reproduction	10	Pollen tube
2	Budding	11	Pollination
3	Embryo	12	Seed dispersal
4	Fertilisation	13	Sexual reproduction
5	Fragmentation	14	Spore
6	Gametes	15	Sporangium
7	Hypha	16	Vegetative propagation
8	Ovule	17	Zygote
9	Pollen grain