How do seeds disperse?

Seeds disperse through five primary methods: gravity, wind, ballistic, water, and animals. Some plants also exhibit serotiny, releasing seeds only in response to specific environmental triggers.

Here's a breakdown of each dispersal method:

• Gravity:

  • This is the simplest method. Heavy seeds simply fall to the ground beneath the parent plant.
  • Example: Apples, acorns.
  • Results in dense clusters of offspring near the parent plant.

• Wind:

  • Seeds are adapted to be lightweight and easily carried by the wind. Some have "wings" or fluffy structures.
  • Example: Dandelions, maple seeds.
  • Can disperse seeds over long distances.

• Ballistic:

  • Plants actively eject their seeds, often explosively.
  • Example: Witch hazel, squirting cucumber.
  • Helps distribute seeds away from the parent plant in a localized burst.

• Water:

  • Seeds are buoyant and can float on water.
  • Example: Coconuts, mangroves.
  • Important for plants near bodies of water.

• Animals:

  • Seeds are dispersed by animals in various ways:
    • Epizoochory: Seeds attach to the animal's fur or feathers. Example: Burdock.
    • Endozoochory: Animals eat the fruit containing the seeds, and the seeds are dispersed in their feces. Example: Berries, apples.
    • Myrmecochory: Seeds have elaiosomes (nutrient-rich appendages) that attract ants. The ants carry the seeds to their nests, providing dispersal and sometimes protection. Example: Bloodroot, trillium.

• Serotiny:

  • Seeds are retained in cones or fruits until triggered by environmental factors such as fire or drought.
  • Example: Lodgepole pine (fire), some eucalyptus species (drought).
  • Releases seeds strategically based on specific environmental conditions.

These dispersal methods are crucial for plant survival, allowing them to colonize new areas, avoid competition with parent plants, and escape unfavorable conditions.