Bryophytes 1

Bryophytes (include what)

• Liverworts

• Hornworts

• Mosses

Will form relationship with lichens

Lichens (basic characteristics)

• Sensitive to air pollution

• Also important for storing carbon

• colonizers of bare rock, soil surfaces

Transitional between charophyte green algae and vascular plants

• Retained features of mitosis: breakdown of nuclear envelope persistent spindle or pheagmoplast during cytokinesis.

Embryophytes

Are called True plants

Embryophytes (general life cycle)

Alternating heteromorphic generations (sporic)

Embryophytes (Forms)

• Thallus (uniform thin flat bodies (no roots, leaves, stem))

• Plant like forms (leafy, no vascular tissue (xylem/phloem))

Bryophytes (characteristics)

Gametophyte larger and free-living

• Sporophyte smaller and permanently attached to gametophyte

Vascular plants (in comparison to bryophytes)

Sporophyte larger than gametophyte and free-living.

Bryophytes (Gametophytes anchored how)

Anchored to substrate by rhizoids.

• Unicellular in liverworts or multicellular in mosses

• Anchoring structure ONLY (NO roots)

Bryophytes (Interconnected cells)

Interconnected by plasmodesmata

Bryophytes (symbiotic relationship)

Can house fungal or cyanobacteria

• Acquisition of mineral nutrients.

Bryophytes (Asexual Reproductive)

Fragmentation + gemma

Gemmae

Multicellular bodies that give rise to gametophytes

Bryophytes (Sexual reproduction parts)

• Antheridia

• Archegonia

Antheridia (look like)

Spherical, elongated, stalked

Antheridia (Consist of)

Sterile jacket layer surrounding spermatogenous cells.

Each spermatogenous cell produces biflagellate sperm

Archegonia (look like)

Flask-shaped, long neck-swollen base

Archegonia (Structure consists of)

• Outer layer: sterile + protective

• neck canal cells break down when egg is mature.

Bryophytes sexual reproduction

Sperm swim to egg in fluid-filled canal (chemicals released to attract sperm (chemotaxis))

After Fertilization (bryophytes)

• Zygote remains in archegonium (which is nourished by sugars and amino acids)(matrotrophy)

• Zygote undergoes multiple mitotic divisions (multicellular embryo which will develop into a sporophyte)

Sporophyte (Bryophytes)

• Nutrient transport between gametophyte + sporophytes

• Transfer cells at interface (placenta)

• Venter becomes calyptra

• Sporophyte is the foot, stalk (seta), capsula (sporangium)

Liverworts: Phylum Marchantiophyta (Characteristics)

• Upper surface of gametophyte thallus has pores

• Thalloid forms:

  • Chlorophyll rich upper portion

  • Rhizoids and scales (lower portion)

Liverwort (examples)

Marchantia

• Gametophytes (unisexual)

• Sporangium produces spores + elaters

Hornworts: Phylum Anthocerophyta (Gametophyte)

Resembles ‘superficially’ thalloid liverworts (rosette-like morphology)

Hornworts (Cavities - Intercellular spaces)

Contain filamentous cyanobacteria Nostoc.

• Nostoc suppled nitrogen to host

• Pores on thallus filled with mucilage (for entry of Nostoc).

Hortworts (Reproduction/gametophytes)

Most gametophytes:

• Unisexual

• Antheridia + Archegonia are sunken in chambers on dorsal surface

Hortworts (Reproduction/Sporophytes)

Green/Photosynthetic

• Dehiscent sporangium splits longitudinally

Hortworts (example)

Anthoceros

• Sporophyte (foot + long capsule)(NO seta)

• Meristematic zone between foot and sporangium.