Kingdom Plantae

Characteristics: Multicellular, Eukaryotic, Autotrophic (Photosynthetic). Cell wall made of Cellulose.

Alternation of Generations: Life cycle alternates between two generations:

• Sporophyte (2n): Diploid, produces spores by meiosis. Dominant in higher plants.
• Gametophyte (n): Haploid, produces gametes by mitosis. Dominant in Bryophytes.

Called 'Amphibians of the Plant World' (need water for fertilization).

• General: No vascular tissue (xylem/phloem). Gametophyte is dominant. Sporophyte is dependent.
• Life Cycle of Moss (Funaria):
  • Spore germinates into filamentous Protonema.
  • Protonema forms leafy Gametophyte bearing Antheridia (Male) and Archegonia (Female).
  • Sperm swims to Egg → Zygote → Sporophyte (Foot, Seta, Capsule) grows on Gametophyte.
  • Capsule releases spores (meiosis).

Have vascular tissues (Xylem/Phloem). Sporophyte is dominant and independent.

Evolution of Leaf:

1. Microphylls: Small leaves with single vein (e.g., Club mosses). Evolved by simple outgrowth.
2. Megaphylls: Large leaves with webbed veins (e.g., Ferns, Seed plants). Evolved from branching systems by: Overtopping (unequal branching) → Planation (flattening) → Webbing (tissue filling spaces).

Include Ferns (e.g., Adiantum).

• Sporophyte: Differentiated into Roots, Stem (Rhizome), and Leaves (Fronds). Bear Sori (clusters of sporangia) on underside of leaflets.
• Gametophyte: Small, heart-shaped, photosynthetic thallus called Prothallus. Independent.

Seed habit success is due to 3 steps:

1. Heterospory: Production of two spore types: Microspores (Male) and Megaspores (Female).
2. Retention of Megaspore: Megaspore is retained inside the Megasporangium (Nucellus).
3. Development of Integument: Protective layers around megasporangium forming the Seed Coat (Testa) after fertilization.

e.g., Pinus. Seeds are exposed on cones (no fruit).

• Cones: Male cones produce Pollen. Female cones produce Ovules.
• Pollination: By Wind (Anemophily).
• Life Cycle: Sporophyte (Tree) is dominant. Gametophytes are highly reduced and dependent.

Seeds enclosed in Fruit.

• Flower: Reproductive part. Sepals, Petals, Stamens (Male), Carpels (Female).
• Double Fertilization: Unique to Angiosperms.
  • 1 sperm + Egg → Zygote (2n).
  • 1 sperm + Secondary Nucleus (2n) → Endosperm Nucleus (3n) (Food storage).
• Classes:
  • Monocots: 1 Cotyledon, Parallel venation, 3-merous flowers (e.g., Grass, Maize).
  • Dicots: 2 Cotyledons, Reticulate venation, 4/5-merous flowers (e.g., Rose, Bean).