bryophytes Flashcards

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1
Q

Land plants differ from Charophyceae by

A
  • Male and female gametangia called antheridia and archegonia that have a protective layer (sterile jacket layer)
  • Zygote and developing embryo are retained within the archegonium on the female gametophyte
  • Sporophyte is multicellular=>increases the number of meiosis and the number of spores produced per single fertilization event
  • Spores with walls containing sporopolleninresist decay and drying
  • Tissues produced by apical meristem
    o Meristem = region of embryonic cells that makes new cells; like stem cells
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2
Q

features

A
  • No vascular plants
    o Lack water (xylem) and food tissues (phloem)
    o So they’re flat to compensate for this
  • Lack true leaves, stems, and roots
  • Have superficial cuticle and pores—liverworts
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3
Q

structure

A
  • Thallose
  • Flat and thin gametophyte—undifferentiated
    o Helps with uptake water and CO2
    o Leaves small w/o veins
    o Stems w/ conducting cells
    o Rhizoids for fixation
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4
Q

asexual reproduction

A
  • Fragmentation or producing gemmae
    o Small pieces of gametophytes are detached and then regenerate an entire gametophyte (identical)
     Liverworts gametophyte produces gemmae in cups and rain helps with dispersal
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5
Q

sexual reproduction

A
  • Gametophytes can be dioecious (male/female) or monoecious (both sex present but separate)
    o Flagellated sperms (n) produced in antheridia
    o Eggs (n) produced in archegonia
     Venter and neck
  • After fertilization the zygote (2n) attached to female develops sporophyte (2n)
    o Female gametophyte (n) provides sugars AA’s = matrotrophy
    o Placenta is transfer of cells with highly branched cell wall ingrowth. Incr. SA
  • Mature sporophyte, meiosis produces spores (n)
    o Spores released from sporangia and dispersed by winds
    o Spores germinate into gametophyte
    o Directly or through protonema in all mosses and some liverworts
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6
Q

Marchantiophyta (Liverworts)

A
  • Leafy and thallose species
  • Gametophyte grows directly from the spore
  • Thin thallus with single celled rhizoids and scales for fixation to rocks and moist soils
  • Gametangia born on gametophores
  • Sporophyte dominant in alga
  • Spore dispersion
    o Released form sporangia and dispersed by wind
    o Elaters are elongated cells that help with dispersion
     Sensitive to humidity
     Twist
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7
Q

Sphagnum Moss

A
  • Abundant
  • Peat is accumulation and compression of sphagnum moss in cold wet places
  • Sphagnum differs from other bryophytes
    o Protonema one layer thick
    o Leaves made of dead cells surrounded by small living cells
    o Absorbs water
    o Explosive operculum
     Burst and spores released
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8
Q

Bryophyta (mosses)

A
  • Leafy gametophytes that develop from buds on filamentous protonemata
  • Have specialized cells for water and food conduction
    o Handrom (central strand) Leptom (surrounds hadrom)
    o Hydriods—transport water/minerals, are elongate cells with end walls , permeable to water , no living protoplasm (DEAD CELLS)
    o Leptoids—conduct sap (water +sugar), elongate cells with end walls, protoplast present at maturity but nucleus is degenerate (LIVING CELLS)
  • Gametangia produced at tip of main axis/lateral branches
  • Sporophytes born on female gametangia
    o Sporophyte grows, venter of archegonium enlarges = calyptra falls off, operculum open to expose peristome
  • stomata
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9
Q

Anthocerophyta (Hornworts)

A
  • Resemble thallose liverworts
  • Symbiotic relationship with cyanobacteria
  • stomata
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10
Q

MABS

A

MARCHANT–LIVERWORTS
ANTHO–HORNWORTS
BRYO–MOSS
SPAGNUM–MOSS

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