RHS Level 2 Certificate Year 1 Week 9 overview

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RHS Level 2 Certificate Year 1 Week 9 overview

  1. 1. RHS Level 2 Certificate Week 9 – Germination and seed dormancy; Introduction to propagation by seed
  2. 2. Learning outcomes <ul><li>Identify three methods of seed dispersal </li></ul><ul><li>Describe ideal conditions for storage of seed </li></ul><ul><li>Name the stages of germination </li></ul><ul><li>State the factors affecting germination of a seed and how dormancy may be broken. </li></ul><ul><li>Define the terms: ‘viability’ and ‘dormancy’. </li></ul><ul><li>Define: ‘epigeal’ and ‘hypogeal’ germination </li></ul><ul><li>Outline the steps to be taken when sowing seeds into a seed tray </li></ul>
  3. 3. Parts of the Seed - review <ul><li>Seed – formed from the mature fertilized ovule and containing the embryo and stored food. </li></ul><ul><li>Parts of the seed – review vocabulary and structure. (Testa, plumule, cotyledons, micropyle, radicle) </li></ul>
  4. 4. Seed Dispersal <ul><li>Animal or bird </li></ul><ul><li>Wind </li></ul><ul><li>Water </li></ul><ul><li>Mechanical </li></ul><ul><li>Enables the seed to germinate away from competition from the parent plant. </li></ul>
  5. 5. Seed Storage <ul><li>Slow rate of respiration within the dormant seed. </li></ul><ul><li>Viable seed is able to germinate if the right conditions are present. </li></ul><ul><li>Seed remains viable for variable periods of time depending on storage conditions and genus/species. </li></ul><ul><li>Successful storage means controlling the limiting factors of respiration to keep the rate within the seed slow. </li></ul>
  6. 6. Germination <ul><li>Stage one (Imbibition phase) – water enters the seed (imbibition). The seed swells and the testa splits </li></ul><ul><li>Stage 2 (Lag phase)– respiration begins to speed up, the food in the cotyledons/endosperm is broken down. Called the ‘lag phase’ because nothing obvious is happening. </li></ul><ul><li>Stage 3 (Emergence phase) – the radicle emerges followed by the hypocotyl and the shoot begins to grow. The process of germination ends when the shoot reaches the surface and begins to photosynthesise. </li></ul>
  7. 7. Key factors for germination <ul><li>Water </li></ul><ul><li>Light </li></ul><ul><li>Temperature </li></ul><ul><li>Oxygen </li></ul><ul><li>Food </li></ul><ul><li>Time </li></ul>
  8. 8. Seed dormancy <ul><li>Dormant – a seed which is viable but unable to germinate, either because the external conditions are not correct or because of factors within the seed itself </li></ul><ul><li>Examples- ‘after ripening’, chemical inhibition, temperature, light (presence or absence), thick seed coat or chemical triggers for germination. </li></ul>
  9. 9. Sowing seeds <ul><li>Equipment needed – seed tray, striking board, presser board, seed compost, sieve, label, indelible pen …and seeds </li></ul><ul><li>Suitable compost? Characteristics </li></ul><ul><li>To cover or not to cover? </li></ul><ul><li>Watering </li></ul>
  10. 10. Learning outcomes <ul><li>Identify three methods of seed dispersal </li></ul><ul><li>Describe ideal conditions for storage of seed </li></ul><ul><li>Name the stages of germination </li></ul><ul><li>State the factors affecting germination of a seed and how dormancy may be broken. </li></ul><ul><li>Define the terms: ‘viability’ and ‘dormancy’. </li></ul><ul><li>Define: ‘epigeal’ and ‘hypogeal’ germination </li></ul><ul><li>Outline the steps to be taken when sowing seeds into a seed tray </li></ul>

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