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Great Oaks from Little Acorns Grow It all starts with a seed

Great Oaks from Little Acorns Grow It all starts with a seed. I Can … Explain the process of seed germination. I Will … Describe conditions for maintaining dormancy and promoting germination List the steps of seed germination. Seed Dormancy Stasis prior to germination Metabolism falls

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Great Oaks from Little Acorns Grow It all starts with a seed

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  1. Great Oaks from Little Acorns Grow It all starts with a seed I Can… Explain the process of seed germination. • I Will… • Describe conditions for maintaining dormancy and promoting germination • List the steps of seed germination

  2. Seed Dormancy • Stasis prior to germination • Metabolism falls • Number of organelles per cell falls • Dehydration – water content falls • Vacuoles in cells deflate • Food reserves become dense and crystalline

  3. Maintaining Dormancy • Physical barriers • Seed coat / Testa is waxy • Waterproof • Impermeable to oxygen • Physical state – dehydrated • Chemical inhibitors present • Salts, mustard oils, organic acids, alkaloids • Growth promoters absent

  4. Seed Viability • Viability: When a seed is capable of germinating after all necessary environmental conditions are met. • Average life span of a seed is 10 – 15 years • Some very short-lived • e.g. willow (< 1 week) • Some very long-lived • e.g. mimosa 221years • Conditions important for longevity: • Cold, Dry, Anaerobic • Conditions maintained in seed banks

  5. Svalbard International Seed Vault • AKA – Doomsday Vault • 2008 • Deep in the side of a frozen artic mountain in Longyearbyen, Norway

  6. Seed Germination – The breaking of dormancy; growth of embryo and its penetration of the seed coat. Breakdown Barriers Abrasion of seed coat (soil particles) Decomposition of seed coat (soil microbes, gut enzymes) Cracking of seed coat (fire) Change in Physical State Rehydration Destruction and Dilution of Inhibitors Light, temperature, water Production of Growth Promoters jump

  7. Kopi Luwak ~Catgut coffee • Refers to the beans of coffee berries once they have been eaten and excreted by the Asian Palm Civet • Can sell for between $100 - $600 per pound Back

  8. Germination Steps: Seed coat breaks down Radicle becomes root Hypocotyl and epicotyl become stem and growth tip Plumule become first photosynthesis leaves

  9. Great Oaks from Little Acorns Grow It all starts with a seed Learning Check: Why does seed viability vary from just a week to hundreds of years in different plant species? Consider environmental factors in your answer.

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