Duration and Setting 45 minutes for initial set up and 3 weeks overall.

Summary
This activity enables students to understand that different indigenous seeds require special conditions to germinate through a hands-on comparison of different seed pre-treatment techniques.

Student outcomes
Students will be able to:

• Analyse what is needed for living things to survive, thrive or adapt.
• Improve their knowledge of indigenous seed biology and the germination process.
• Draw conclusions about which pre-treatment technique is best for successful wattle seed germination.
• Conduct an experiment using scientific method with variables and a control.

Background notes for teachers
The seeds of acacias (wattles) possess a thick seed coat. This prevents entry of water and protects the seed from predators until conditions are right for germination. In nature, this may occur following a bushfire. Fire can be used in bushland areas to promote germination of wattles; however care must be taken to avoid damage to other fire-sensitive and juvenile plants. Scarification can also be used to damage the seed coat of a wattle to encourage germination.

The seed of most wattles will require pre-treatment to damage the seed coat (dark black outer layer) for successful propagation. To do this there are various options. The most widely used treatment for medium quantities of seed is placing in hot water and then let stand until cooled. This imitates the natural heating of a fire. Note that some species do not require heat treatment and others are sensitive to prolonged heating. A sample of each seed lot should be tested for germination before treating the entire batch. Nicking the seed coat with a single-sided razor-blade is suitable for small quantities. Other treatments include acid scarification (H2SO4, 20 minutes), microwaving (2 minutes), sand papering for scarification and machine scarification.

Materials

• Labels
• Trowels
• Hyco trays
• Batches of 'Blackwood' Acacia seeds - approximately 50 seeds per group
• Beakers or cups for each seed sample treatment (5 per group)
• Sandpaper
• Potting mix [Safety alert: Wash hands after use and avoid inhalation]

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