BY5.3 Flower Structure

Plant Reproduction

flowering plants are called angiosperms

flower structure:

• diploid
• meiosis occurs to produce haploid spores

• meiosis in the anther occurs to produce pollen which contains hapolid gametes
• ovules are made in the ovary, the female gametes develop inside the ovule

• pollen grains are transferred from one plant to the female part of a plant in the same species - this is known as pollination
• pollen grains: tough resistant wall to prevent it from drying out during transfer
• male and female gametes fuse during fertilisation
• fertilised ovule becomes the seed

• the structure of the plant depends on the pollination method

Insect pollinated plants:

Sepal:

• green
• protect the flower bud

Petals:

• brightly coloured
• scented
• produce nectar

Stamens:

• consists of an anther and a filament
  • anther:
    • produces pollen
    • made up of four pollen sacs in pairs, side by side
    • when mature, the sac splits to release pollen
  • filament:
    • contains vascular tissue that transports material neccessary for the production of pollen

Carpel:

• closed structure in which the ovule develops
• consists of an ovary, a style and a stigma
  • ovary:
    • lower part that surrounds the ovule
  • …