Seed structure

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Seed structure

  1. 1. Notes:Seeds
  2. 2. What is a seed?• A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food.• The formation of the seed completes the process of reproduction in seed plants.
  3. 3. Why are seeds advantageous for plants?• maintain dormancy until better environmental conditions arise• afford protection to young plant at vulnerable developmental stage• contain adequate food supply until photosynthesis is possible• dispersal of plants
  4. 4. SEED STRUCTURE• External – Seed coat (testa) – Hilum• Embryo – Cotyledon – Epicotyl / Hypocotyl – Pumule – Radical
  5. 5. Seed Coat• AKA testa• The seed coat protects the embryo• Can be of varying thicknesses, depending on the seed type.
  6. 6. Hilum• Scar from the seed being attached to the parent plant
  7. 7. Embryo• The embryo is what forms the new plant once the opportune conditions are present.
  8. 8. Cotyledon• The cotyledon is the first leaf that germinates.• It is filled with stored food that the plant uses before it begins photosynthesis.• Some plants have 1 cotyledon (monocot) and some have 2 cotyledons (dicot).
  9. 9. Epicotyl /Hypocotyl• The basis for the plant’s stem.• It is known as the epicotyl above the cotyledon and a hypocotyl below the cotyledon.• These grow upward in response to light.
  10. 10. PlumuleThe shoot tip with a pair of miniature leaves.
  11. 11. The Radicle• The part of the seed where the root develops.
  12. 12. SEED STRUCTURE• Seed coat (testa)• Embryo – Cotyledon – Epicotyl / Hypocotyl – Pumule – Radical
  13. 13. SEED DISSECTION• MATERIALS – Soaked pinto seed – Dissecting microscope – Tweezers – Ruler
  14. 14. SEED DISSECTION• EXTERNAL • INTERNAL – Draw the external pinto – Carefully remove the seed bean coat. – Label structures from – Gently pull apart the two notes halves of the seed. – Examine each half with the dissecting microscope – Draw what you see inside the bean – Label structures from notes REVIEW THE RULES FOR LAB DRAWING IN YOUR STUDENT GUIDEBE SURE YOU MEASURE AND RECORD THE LENGTH OF YOUR SEED
  15. 15. Plumule Epi c y HypocottyllEmbryo Cotyledon Radicle

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