BOTANY - BIO 2500 -- LECTURE 19
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20
Lower Vascular Plants - Ferns and Allies


Lower Vascular Plants  Kean Lab Help   Help find a Lower Vascular Plant for lab

still under construction
Psilotum Lycopodium Equisetum Fern Selaginella

quiz quiz Survey

Migration to Land Hypothesis
  1o vs 2o invaders (fungi)

Green Algae Land Plants
 
 

Major Problems
 
1. Obtaining reliable source of H2O Absorb
2. Retaining H2O Dessication
3. Transport H2O, ions and food Conduct
4. Gravity Support, no bouyancy
5. Protect and dispersal  air borne, later animals
Also:
1. greater range of temperature fluctuation
2. more light

Strategies

  • 1. Avoid  - e.g. live in wet areas on land  -  liverworts
  • 2. Evade - e.g. short life cycle, dormant
  • 3. Cope
  • Dual environment  soil -- air
  • Adaptations
  • Adaptations of Green Land Plants
    1. Roots and/or rhizoids  absorb water
    2. Cuticle  + stomates  retain water 
    3. Vascular Tissues   transport water and nutrients
    4. Lignin + highly refined geotropism support
    5. Gametes in jacket of sterile cells  protect
        Egg retained (Fertilized within sex organ)
        Embryo -- formed and held in parent tissue
       Cutinized air borne spores or seeds disperse

    Why selected for ?
    What adaptive significance? selection pressure ?
     

    Not Pre-adaptation !


    Adaptations that help water plants live in water that also made land possible

    Analogy -- space technology suited to land

    No adaptive significance in normal conditions
         but
    Might be significant in special conditions

    Example:

    Seasonal drought
    H2O level drops
    Small ponds dry completely
        Plants die
        Must reinvade


    Waterproof covering (cuticle)
           last longer --- out produce
          survive mild drought (head start following season)
    Windblown spores
          Move to larger ponds or wet areas
     



     
     
     
    . Green Algae "Bryophytes" Vascular Plants
    Structure . . .
       Root, stem, leaf - - +
       Vascular tissue - - +
       Tissue systems - - +
    H2O Conservation . . .
       Cuticle - some mosses +
       Stomates - sporophytes of some mosses +
    Reproduction . . .
       2N dominant - - +
       Heterogamy - + +
       Multicell sex - + +
       Embryo - + +

     
     

    Lower Vascular Plants

    Like the Bryophytes

  • Multicell sex with sterile cells antheridia  + archegonia
  • Flagellated, free-swimming sperm (Land -- but still dependent on free H2O)
  • Non-motile egg
  • Embryo
  • 2N retained in early development
  • Nourished
  • Protected
  • Alternation of multicellular sporophyte and gametophyte
  • Most are homosporous (Selaginella is heterosporous)
  • Differ from Bryophytes
  • Most have root, stem and microphyllous "leaves" (megaphyll in fern)
  • Vascular tissues - xylem and phloem
  • 2N Dominant
  • 2N free-living at maturity (N also free living, non-green saprophyte in some)
  • Differ from higher vascular plants
  • Homospory (in most)
  • No seeds
  • Lack cambium

  • Lower Vascular Plants - Ferns and Allies
      Vascular tissue
      2N Dominant
      Most homosoporous
      No seeds
      Lack cambium
    Division Psilophyta Lycophyta Sphenophyta Pterophyta
    . Whisk Fern Club Mosses Horse Tail Ferns
    . Psilotum Lycopodium Equisetum Polypodium
    Root -   *rhizoid root root root
    Leaf +,-
    microphyll
     microphyll microphyll,
    whorls
    megaphyll, alternate
    Stem dichotomous . jointed, ridged .
    Sporangia short branch or branch tip,3 lobes,
    3 chambers,
    synangium
    axillary or upper base of leaf sporangiophore sori
    .
    Selaginella
    Gametophyte subterranean subterranean
    or green
    subterranean 
    or green
    green
    Sperm multiflagellate biflagellate multiflagellate multiflagellate
    Life Cycle Psilotum Lycopodium
    Selaginella
    Equisetum Fern
    *rhizome with endomycorrhizal zygomycete   Table of characteristics- Konig   Key
    Phylum directory
     
     
     
     
     
     

    Psilotum
     

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Psilophyta/Psilotum_habit

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Psilophyta/
    Psilotum_enations_and_sporangia

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Psilophyta/Psilotum_sporangium_d
    Life Cycle Diagram

    Lycopodium

    http://www.csdl.tamu.edu/
    FLORA/Fern&Gym/
    F&G004.jpg


    gopher://wiscinfo.wisc.edu:2070
    /I9/.image/.bot/.130/Fern_Allies/
    Lycophyta/Lycopodium/
    Plant_with_Strobilus_d

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Fern_Allies/Lycophyta/
    Lycopodium/Sporophylls_d

    gopher://wiscinfo.wisc.edu:2070
    /I9/.image/.bot/.130/
    Fern_Allies/Lycophyta/
    Lycopodium/Strobilus_d

    Equisetum

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/Fern_Allies/
    Sphenophyta/Equisetum/
    Equisetum_arvense_d

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/Fern_Allies/
    Sphenophyta/Equisetum/
    E._laevigatum_KS

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Sphenophyta/Equisetum/
    Strobilus_sporangiophores_d

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/Fern_Allies/
    Sphenophyta/Equisetum/
    Strobilus_composite_d

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Fern_Allies/Sphenophyta/
    Equisetum/Equisetum_spores

    Fern
     

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Ferns/Gametophyte_Images/
    Composite_view_d

    http://raider.grcc.cc.mi.us/
    biosci/pictdata/bi103/560-ml.jpg
    fern sperm
      sperm

    http://raider.grcc.cc.mi.us/
    biosci/pictdata/bi103/560-fl.jpg

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Ferns/Gametophyte_Images/
    Antheridium_ls_d_130

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/Ferns/
    Gametophyte_Images/
    Sperm_and_achegonium_d

     


    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Ferns/Sporophyte_images/
    Fern_labeled

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Ferns/
    Sporophyte_images/
    Circinate_Vernation/
    Osmunda_cinnamomea_KS
    Circinate vernation

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Ferns/
    Sporophyte_images/
    Adiantum_rhizome_leaf_gap_c

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Ferns/Sporophyte_images/
    Dicksonia_rhizome_400_x_d

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Ferns/Sporophyte_images/
    Cyrtonium_indusium_xs_d

    gopher://wiscinfo.wisc.edu:2070
    /I9/.image/.bot/.130/Ferns/
    Sporophyte_images/
    Cyrtomium_sori_with_indusia_d

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Ferns/
    Sporophyte_images/
    Sporangium_transverse_annulus_d

    http://www.umanitoba.ca/
    faculties/science/
    biological_sciences/
    lab7/images/sori.gif

     
    Ferns
     

    Ferns - life cycle,
    relationships


    http://www.umanitoba.ca/
    faculties/science/
    biological_sciences/lab7/
    images/ferngamwspor.gif
    Life cycle

    Circinate vernation
    Circinate -- rolled in coil on its axis with apex in center  cir = round
    Vernation --- arrangement of leaves in a bud              vern = spring
     

    Heterospory vs Homospory
     
     
    Homospory Heterospory
    Most Ferns, Psilophyta, Sphenophyta, some Lycophyta Selaginella, a few ferns (Salvinia, Marselia), all *seed plants
    one type of spore two types of spoes, often large + small
      Megaspores
      Microspores
    one type of sporangium two types of sporangia
      Megasporangia
      Microsporangia
    one kind of gametophyte two types of gametophytes
      megagametophyte
      microgametophyte
    bisexual gametophyte Unisexual gametophyte
       most important distinction
    * seed plants are functionally heterosporous (megaspore size may be <, > or = microspore)
      Megaspore size reduced when became permanently retained in sporangium

    Selaginella Lycophyta-Selaginellales-1    nice information and images

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Lycophyta/Selaginella/
    Selaginella_apoda_KS

    gopher://wiscinfo.wisc.edu:2070/I9/
    .image/.bot/.130/Fern_Allies/
    Lycophyta/Selaginella/
    Selaginella_branch

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Fern_Allies/Lycophyta/
    Selaginella/Strobilus_d

    http://www.botany.hawaii.edu/
    faculty/webb/BOT201/
    Selaginella/LeafCloseUp-3-Lab.jpg

    http://home.uleth.ca/
    bio/bio1020/images/sel4b6.jpg

    gopher://wiscinfo.wisc.edu:2070/
    I9/.image/.bot/.130/
    Fern_Allies/Lycophyta/
    Selaginella/Sporophylls_d

    Gametophyte Development
    http://www.botany.hawaii.edu/
    faculty/webb/BOT201/
    Selaginella/
    Megagametophyte240Lab.jpg


    http://www.botany.hawaii.edu/
    faculty/webb/BOT201/Selaginella/
    GametoSporo240Lab.jpg

    http://home.uleth.ca/bio/
    bio1020/images/sel6b6.jpg

    http://www.botany.hawaii.edu/
    faculty/webb/BOT201/
    Selaginella/ArchClose400Lab.jpg
    Life cycle

    Life cycle - do it yourself


     
    Microphyll - no leaf gap Microphyll-  no leaf gap
    Sporophyll - spore bearing leaf Sporophyll - spore beariang leaf
    Megasporophyll Microsporophyll
      Megasporangium   Microsporangium
      Megaspore mother cell   Microspore mother cell
          meiosis       meiosis
     Megaspores
        large
        thick-walled
       1-4 per sporangium
       white to yellow
      Microspores
        smaller
        thin-walled
        numerous
        orange

     

    Selaginella
      Points of special note (for evolution toward land plants)

  • 1. Gametophytes retained with spore wall - -  endosporic
  • 2. Gametophytes reduced and dependent
  • 3. Gametophytes unisexual
  • 4. Less dependence on free water for fertilization
  • 5. Role of gametophyte reduced to protection and nutrition of embryo



  • Looking Ahead

    Preface to Seed Plant

    Greater adaptation to terrestrial life

    Increased protection of sporangia
       Megaspores retained
       Microgametophyte released, megagametophyte retained  (by parent sporophyte tissue -- within integument of ovule in gymnosperms, within integuments of ovule and wall of carpel in angiosperms)

    Reduction of gametophytes
      Size decreases
      Vegetative cells reduced, essentially lost
       Sterile jacket reduced or lost
       Increased protection (enclosed)

    Free water not needed for fertilization
      Free swimming sperm --> pollen tube + flagellated sperm  --> pollen tube + sperm nuclei

    Nutrition of embryo
         More reliable food source

    Resting stage (seed)
     



    Microphyll vs Megaphyll

    Microphyll Megaphyll
    "small" + "leaf" "large" + "leaf"
    Psilophytes (but not Psilotum), Lycopods, Horsetails Fern, Seed plants
    Usually small often large
    simple simple or compound (often blade & petiole)
    1 or no Vascular strand
      central
      unbranched
    1 or more vascular strands
      branched
    typically on protostele
     Equisetum has microphyll on eustele
    typically on siphonostele (hollow cylinder)
     or eustele (strands)
    mesophyll of uniform parenchyms often palisade and spongy
    may have stomates stomates typical
    No leaf gap leaf gap

     
     

    Find a lower vascular plant for Lab
     
  •  Where to look
  • At this time of year you may have difficulty collecting lower vascular plants growing outdoors. I  have several ferns growing in my yard that retain their foliage so that I can find them even after most other plants have lost their leaves. Spike mosses grow as weeds near one edge of my vegetable garden. Also, I know where I can collect club mosses on some land that I own. However, I suggest that you look for one of the many ferns that are grown as houseplants. Perhaps ask an aunt, grandparent or friend who does have ferns as houseplants if you can take one of the compound leaves for your class project.
     

    What to look for

    Ferns grow well as houseplants is the proper varieties are selected and provided with suitable conditions. Most ferns have compound leaves (fronds) that are highly dissected. Young fronds are curled and unroll as they mature. Stems are often short and coated with brownish "fuzz" or scales. Spore producing structures may be seen on the lower surface of some fertile fronds. If the fern has spores I will appreciate your bringing a leaf with spores to lab. 

    You need collect and bring to lab only a single leaf.

    If you have access to other lower vascular plants you may elect to bring a club moss, spike moss, etc. instead of a fern.
     


     
     
     
     
     
     
     
     
     
     

     
     
     




     
     
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    BOTANY - BIO 2500 -- LECTURE 19
         Principles of Botany
              Bio. 2500