Lesson 3 ·Class 9 · Pollination and Fertilization · Match Lab
How Nature Forces Cross-Pollination
Devices that stop a flower fertilising itself.
Match each device to how it prevents self-pollination.
Matched 0/6
Free play — tap an item on the left, then its partner on the right; each link tells you why. Switch to when you're ready to test yourself.
They separate the sexes in space (unisexuality, heterostyly), in time (dichogamy), or chemically (self-sterility).
What this lesson covers
Challenges to clear
- Match every device.
- Connect protandry to what matures first — the trap here is protogyny.
The task
Match each device to how it prevents self-pollination.
What this lesson covers
- Unisexuality — The flower has only stamens or only carpels (With one sex missing, self-pollination is simply impossible.)
- Dichogamy — Anthers and stigma mature at different times (By the time the stigma is ready, the flower's own pollen is gone.)
- Protandry — The anthers mature before the stigma (As in sunflower and cotton — pollen is shed too early to be used.)
- Protogyny — The stigma matures before the anthers (As in custard apple — the stigma is receptive before pollen exists.)
- Heterostyly — Styles and stamens are of different lengths in different flowers (An insect picks up pollen at one height and deposits it at that height in the other form.)
- Self-sterility — The plant's own pollen fails to germinate on its own stigma (A chemical block — the last line of defence, as in tobacco.)
Hint
They separate the sexes in space (unisexuality, heterostyly), in time (dichogamy), or chemically (self-sterility).