Lecture: Reproduction in Flowering Plants

Key Concepts

• Focus on the reproduction of flowering plants.
• Introduction to new terminology related to plant life cycles.
• Understanding the life cycle phases: gametophyte and sporophyte.

Alternation of Generations

• Gametophyte: Haploid and multicellular, produces gametes via mitosis.
• Sporophyte: Diploid and multicellular, produces spores via meiosis.
• Meiosis: Transition from diploid to haploid.
• Mitosis: For other transitions.
• Alternation between haploid and diploid phases.

Mosses as an Example

• Mosses are examples of early land plants.
• Gametophyte dominant: Majority of life spent in the haploid stage.
• Gametophyte Structure: Multicellular, photosynthetic parts, and reproductive structures.
• Sporophyte Structure: Grows from the gametophyte after fertilization.

Reproductive Structures

• Archegonium: Female structure containing the egg/ovule.
• Antheridium: Male structure releasing sperm.
• Fertilization requires water for sperm to swim to the egg.

Life Cycle of Moss

• Life cycle includes gametophyte and sporophyte stages.
• Sporangium: Structure where spores are produced by meiosis.
• Mother Cell: Undergoes meiosis to produce spores.

Comparison with Human Reproduction

• Spermatocyte: Human male cell that undergoes meiosis.
• Mother Cell: Plant equivalent, produces spores.

Evolution of Plant Reproduction

• Differences among moss, gymnosperm, and angiosperm life cycles.
• Gymnosperms: Vascular plants like pine trees, use pollen for reproduction.
• Angiosperms: Flowering plants, have separate male and female gametophytes.

Mega and Micro Terms

• Mega: Refers to female structures, e.g., megaspore mother cell.
• Micro: Refers to male structures, e.g., microspore mother cell.

Angiosperm Reproduction

• Female Gametophyte: Develops from megaspore.
• Male Gametophyte: Develops from microspore.
• Embryo Sac: Female gametophyte in angiosperms.
• Pollen: Male gametophyte in angiosperms.

Final Notes

• Understanding these concepts helps in comprehending angiosperm reproduction.
• The lecture sets the foundation for discussing angiosperm reproduction in the next class.