Bryophytes quiz study

🌿 Study Guide: Bryophytes and Pterophytes

Domain & Kingdom

  • Domain: Eukarya

  • Kingdom: Plantae

🪴 Bryophytes (Non-Vascular Plants)

Divisions:

  • Marchantiophyta → Liverworts

  • Bryophyta → Mosses

  • Anthocerotophyta → Hornworts

Key Traits

  • Earliest diverging land plants.

  • Grow in moist environments — need water for sperm to swim to egg.

  • No vascular tissue (xylem/phloem).

  • No roots, only rhizoids (for anchoring).

  • Dominant generation: Gametophyte (n)

  • Dependent generation: Sporophyte (2n)

Alternation of Generations in Bryophytes

  1. Sporophyte (2n): Undergoes meiosis → produces haploid spores (n).

  2. Spores germinate → form gametophyte thallus (n).

  3. Gametophyte reproduces:

    • Asexually: via gemmae cups (containing gemmae clones).

    • Sexually: via gametangiophores.

  4. Fertilization: Sperm (from antheridia) → egg (in archegonia) → zygote (2n).

  5. Zygote → new sporophyte, dependent on gametophyte for nutrients.

Reproductive Structures

Structure

Function

Antheridiophore

Male structure; flat-topped with antheridia containing flagellated sperm.

Archegoniophore

Female structure; has hanging lobes with archegonia containing eggs.

Sporangium

Capsule where meiosis → haploid spores occur.

Gemmae Cups

Hold asexual propagules (gemmae) for cloning.

Rhizoids

Thread-like anchoring cells, not true roots.

Calyptra

Protective covering around developing sporophyte.

Examples

Marchantia (Liverwort)

  • Flat, green thallus (gametophyte).

  • Gemmae cups visible on surface (asexual).

  • Antheridiophores and archegoniophores arise from thallus (sexual).

Mnium (Moss)

  • Green leafy part = Gametophyte (n).

  • Brown stalk + capsule = Sporophyte (2n).

  • Archegonia face upward; sperm splashed by rain.

🌱 Pterophytes (Ferns and Allies)

Key Traits

  • Vascular plants → have xylem (water) and phloem (nutrients).

  • Dominant generation: Sporophyte (2n).

  • Small gametophyte (n) still depends on water for fertilization.

  • Examples of related divisions:

    • Sphenophyta (horsetails – Equisetum)

    • Lycophyta (club mosses – Lycopodium, Selaginella)

    • Psilophyta (whisk ferns – Psilotum)

Sporophyte (2n)

  • True roots, stems, and leaves called fronds.

  • Underground stem = rhizome.

  • Vascular tissue:

    • Xylem: thick-walled, water transport.

    • Phloem: thin-walled, food transport.

    • Sclerenchyma: support tissue.

  • Sporangia grouped in sori under fronds.

    • Each sorus may be covered by an indusium (protective flap).

    • Annulus: thick ring of cells that flings spores out when dry.

Gametophyte (n): Prothallus

  • Small, green, heart-shaped plant.

  • Anchored by rhizoids.

  • Antheridia (sperm) on edges.

  • Archegonia (eggs) near the cleft.

  • Requires water for sperm to swim to egg.

  • After fertilization → zygote → young sporophyte with roots and leaves.

Alternation of Generations in Pterophytes

  1. Sporophyte (2n) produces spores (n) in sporangia (by meiosis).

  2. Spores → gametophyte (prothallus) by mitosis.

  3. Antheridia + archegonia on prothallus produce gametes.

  4. Fertilization → zygote (2n) → new sporophyte.

Key Terms Summary

Term

Definition

Thallus

Flat, photosynthetic body of liverwort gametophyte.

Rhizoids

Root-like filaments for anchorage.

Gametophyte

Haploid (n) generation that produces gametes.

Sporophyte

Diploid (2n) generation that produces spores.

Antheridia

Male structures that make sperm.

Archegonia

Female structures that hold eggs.

Sporangium

Structure where spores are produced by meiosis.

Gemmae

Asexual reproductive discs in liverworts.

Sorus (sori)

Cluster of fern sporangia on the underside of fronds.

Indusium

Membranous covering over a sorus.

Annulus

Ring of cells that releases fern spores.

Prothallus

Fern gametophyte (heart-shaped).

Rhizome

Horizontal underground stem in ferns.

Xylem & Phloem

Water and nutrient transport tissues.