Seed Notes

Requirements for germination:

  1. Water imbibition
  2. Oxygen
  3. Temperature
  4. Light (absence or presence)

Seed Dormancy

  1. Seeds will not always germinate immediately - dormancy
  2. Seed dormancy can be advantageous to a plant:
    1. Await better environmental conditions.
    2. Synchronize to the environment.
    3. Disperse external arrow to new habitats by wind, water, animals.
  3. There are two general categories of dormancy:
    1. seed coat dormancy
      1. Growth inhibitors in the seed coat.
      2. Impermeable seed coats may require scarification.
    2. embryo dormancy
      1. Further embryo development needed.
      2. Physiological dormancy due to growth inhibitors needing to be broken down.
  4. Breaking dormancy:
    1. Scarification - mechanically breaking the seed coat. (Serotinous plants require a fire - lodgepole pine).
    2. Stratification - cold moisture regime to simulate winter.
    3. Leaching - water to remove inhibitors.

Advantages of propagation by seed:

  1. Genetic diversity greater (also disadvantage)
  2. Lower costs
  3. Might be only method- vegetative propagation not possible.
  4. Can create many, many plants - annuals & biennials.
  5. Disease issues

Disadvantages of propagation by seed:

  1. Slower
  2. Disease issues