IB DP Biology: HL复习笔记9.4.3 Skills: Drawing Plant Structures

• A seed consists of several parts which can be shown in a labelled diagram
  • Testa
    • The seed coat
  • Cotyledon or cotyledons
    • The leaf or leaves of the embryo which sometimes contain the food source for the growing embryo
    • Some plants have one cotyledon and are known as monocotyledonous, and some have two and are dicotyledonous
    • In some plants the food source is separate from the cotyledons and is called the endosperm
  • Embryo plant
    • Consisting of the embryo root and embryo shoot
  • Micropyle
    • A hole through the testa found near the scar tissue where the seed was attached to the parent plant

The internal and external structure of a bean seed

• Animal pollinated flowers have several features in common which should be included in a labelled diagram
  • Nectary
    • Nectar secreting glands to attract pollinators
  • Petals
    • Brightly coloured to attract pollinators
  • Sepals
    • Protect the unopened flower
  • Stamen, which consists of
    • The anthers which produce and release pollen
    • The filaments which hold the anthers in position
  • Carpel, which is made up of
    • The stigma which receives the pollen
    • The style which connects the stigma to the ovary
    • Ovary which contains the ovules
      • Ovules contain the female sex cells

Animal pollinated flowers have structures that attract pollinators and aid the process of pollination