Plant Biology Notes

Plant Families

Nonvascular Plants

  • Require close association with water.
  • Lack a method of transportation up and down the plant, necessitating a location on moist ground.
  • Reproduce via alternation of generations, with the gametophyte generation being dominant.
  • Antheridium: Male reproductive structure.
  • Archegonium: Female reproductive structure.
  • Bryophytes: Mosses.
  • Hepaticophyta: Liverworts.
  • Anthocerophytes: Hornworts.

Seedless Vascular Plants

  • Possess vascular tissue for transporting materials up and down the plant.
  • Reproduce with alternation of generations, where the sporophyte generation is the dominant form.
  • A strobilus releases spores that grow into gametophytes.
  • Lycophytes: Club and spike mosses.
  • Arthrophytes: Horsetails.
  • Pteridophytes: Ferns.

Monocots vs Dicots

  • Seed leaf: Cotyledon.
  • Seeds can be monocotyledon or dicotyledon.
  • Monocots:
    • Have one seed leaf.
    • Leaves and flowers with multiples of 3 petals.
  • Dicots:
    • Have two seed leaves.
    • Flowers with multiples of 4 or 5 petals.

Plant Hormones

  • Auxins: Plant hormones that promote cell elongation.
  • Gibberellins: Promote plant growth.
  • Cytokinins: Stimulate cell division.
  • Ethylene: Gas that promotes ripening.

Plant Tropism

  • Phototropism: Plants grow towards sunlight.
  • Geotropism: Stems grow up and roots grow down.
  • Thigmotropism: Growth response to touch.
  • Hydrotropism: Roots grow toward a water supply.

Seeds

Advantages of Seeds

  • A seed consists of an embryo and its food supply enclosed in a protective coat.
  • Seeds contain enough food to nourish the embryo and plant during early growth stages.
  • The embryo is protected during harsh conditions.
  • Seeds can be easily dispersed to new areas.

Photosynthesis

Chemical Equation for Photosynthesis

  • 6CO2 + 6H2O \rightarrow C6H12O6 + 6O2
  • Products: Glucose (C6H12O6).
  • Reactants: Carbon dioxide (CO2) and water (H2O).