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Extreme Plants

Too hot, too cold or just right? See how these plants adapt to extremes

Australian Curriculum links

  • Science > Biological sciences > Year 5 > ACSSU043
  • Science > Biological sciences > Year 6 > ACSSU094

You’ll need

  • Three types of seedlings
    • These can be from a previous activity, seeds, a living herb pot from the supermarket vegetable aisle or the nursery
  • Potting mix
  • Sand
  • Six pots or empty seedling punnets
  • Plastic trays to collect dripping water
  • A spray bottle
  • Access to: a freezer, fan, heater or heat lamp

Try this

  1. Pot up one of each type of seedling into six pots or punnets using the potting mix and mist with water. You might like to allow your seedlings to settle for one week in a mild light, misting with water every second day. Leave one tray of plants in this position
  2. Place one tray in the freezer overnight, return to the mild light, mist with water every second day and observe what happens.
  3. Place one tray in front of a heating outlet, heat lamp or very warm sun (depending on your climate). Leave here for the duration of the activity, misting with water every second day.
  4. Place one tray in front of a fan or ventilation system outlet that is regularly blowing air. Leave here for the duration of the activity, misting with water every second day.
  5. Place two trays in mild light. Mist one with water twice a day, but mist the other every four days. Be careful not to confuse the two!
  6. Allow the plants to grow for at least two weeks, comparing the differences. Allow them to grow for longer if possible.

Further investigation

  • Try different seedlings and observe how they grow in each of the extreme situations.
  • Can you think of other extreme conditions that plants grow under (e.g. in rocky or sandy ground, acidic soil)? Can you test how plants would grow in these conditions?
  • There is evidence that plants communicate with each other. How could you test if plants grow better closer to each other or further away? Do some plants mix better with others?

Real world links

Plants can grow in some very extreme situations. In the Lake Taupo volcanic region in New Zealand, the dwarf swan neck moss grows at 72°C in very acidic and metallic soils. In soils just a few degrees cooler, there are other mosses and even a shrub that grow at 68°C. These plants adapt to the hot soils by having very short root systems because the soil becomes hotter the deeper they grow.