Flower Structures and Pollination

Absence of Flower Parts

• Definition of Flower Types:
  • Male Flower: Lacks gynoecium (female parts).
  • Female Flower: Lacks androecium (male parts).
  • Sterile/Neutral Flower: Contains neither male nor female parts.

Monoecious Plants

• Definition: Plants that bear separate male and female flowers on the same individual.
• Meaning of Monoecious: The term means "one house," indicating the presence of both male and female flowers on the same plant.
• Examples:
  • Corn (Zea mays): Male flowers (tassels) produce pollen at the top of the plant, while female flowers (silks) are located lower down.
  • Melons, Pumpkins, and Zucchinis: Require manual pollination; male flower pollen must fertilize female flowers, which can be a learning process for new growers.
• Fertility Process:
  • Male flowers release pollen, which needs to reach the elongated stigma of the female flowers to result in fertilization.

Example of Corn (Zea mays)

• Male Flower:
  • Located at the top of the plant (tassels).
  • Produces pollen without any female parts.
• Female Flower:
  • Known as silk, located lower down on the plant.
  • Features:
  • Elongated style (green part)
  • Sticky stigma (pink part) to catch pollen.
  • Result: The fertilized ovary develops into kernels of corn.

Dioecious Plants

• Definition: Species where male and female flowers are found on separate plants.
• Meaning of Dioecious: The term means "two houses," indicating that male and female reproductive parts are on different individuals.
• Examples:
  • Papaya: Male and female flowers occur on different plants, with the former pollinating the latter.
  • Ginkgo (Ginkgo biloba) and Willows (Salix spp.): Require proximity of male and female plants for fertilization.

Example of Papaya

• Male Flower:
  • Found in clusters and contains yellow anthers; lacks female reproductive parts.
  • Emits a pleasant scent to attract pollinators.
• Female Flower:
  • Different shape with a prominent ovary and style.
  • Characterized by a curly stigma to facilitate pollen capture from visiting insects.