9/24/13 1 EVOLUTION AND DIVERSITY OF VASCULAR PLANTS
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EVOLUTION AND DIVERSITY OF VASCULAR PLANTS
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WHAT IS A TRACHEOPHYTE (VASCULAR PLANT)?
A Land Plant (embryophyte) with:
vascular tissue (xylem & phloem)
-functions in conduction of water/sugars
TRACHEOPHYTES ALSO HAVE:
Sporophyte dominant & independent
Supportive tissue (lignified 2˚ cell walls;
sclerenchyma)
Roots
Shoots (w/ sporophytic leaves)
}
extant
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LIGNIN ¢ Polymer of complex compound ¢ Incorporated into secondary wall
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SECONDARY CELL WALL - CELLULOSE + LIGNIN -FORMS BETWEEN 1˚ CELL WALL AND PLASMA MEMBRANE - ADDS STRUCTURAL SUPPORT - FOUND IN TRACHEIDS, VESSELS, FIBERS (ALL DEAD CELLS)
LIGNIFIED SECONDARY CELL WALL
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Sclerenchyma ¢ Secondary cell wall (+ primary)
¢ Dead at maturity (usually)
1. Fibers
Elongate, sharply tapering
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FIBERS
¢ Mechanical support ¢ Occur in groups or bundles ¢ Components of vascular tissues
Sclerenchyma • Permits the plant to attain greater stem of height
2. Sclereids - Isodiametric to irregular - Branched
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What is the function of tracheary elements? In what tissue are the tracheary elements found?
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TRACHEARY ELEMENTS
Tracheids - Imperforate Vessels - Perforate
Angiosperms (most)
Gnetales
A few Monilophytes
SIEVE ELEMENTS Sieve cells - No sieve plates
Sieve tube members - Sieve plates
=Apomorphy of Angiosperms
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Endodermis Casparian Strip: forces fluids from outside
through plasma membrane = selective absorption
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
“Bryophytes”: Gametophyte dominant, long-lived
BRYOPHYTES (LIVERWORTS, HORNWORTS, MOSSES): GAMETOPHYTES ARE DOMINANT, LONG-LIVED
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GAMETOPHYTE(n)
Egg (n)
Sperm (n)
Zygote
(2n)
HAPLODIPLONTIC("Alternation ofGenerations")
SPOROPHYTE(2n)
Embryo(2n)
Spores(n)
lost by reduction and modificationin the Angiospermsand some Gnetales
Sporangium(2n)
Archegonium(n)
Antheridium(n)
fertilization
mitosismitosis
meiosis
mitosis
}(Sperm non-flagellate in Conifers, Gnetales, and Angiosperms)
Sporocyte(2n)
produce
Alternation of Generations: Haploid (n) & Diploid (2n) adult phases
Vascular Plants: Sporophyte dominant, long-lived
VASCULAR PLANTS: SPOROPHYTES ARE DOMINANT
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lateral branch
root
shoot
axillarybud
shootapex
lateralbranch
nodeinternode
root tip
root apicalmeristem
root cap
root hairs
shoot tip
shoot apicalmeristem
budprimordium
lateral roots
SPOROPHYTIC LEAVES AND SHOOTS
Leavesà The same with Mosses and Liverworts?
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Do bryophytes have roots?
DIVERSITY OF VASCULAR PLANTS
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VASCULAR PLANTS
¢ Rhyniophytes ¢ Lycopodiophyta ¢ Euphyllophytes
� Equisatales � Marattiales � Polypodiales � Ophioglosalles � Psilotales � Seed plants
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Rhynia - one of earliest vascular
plants (ca. 400 million years
ago) - lacked roots and leaves
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LYCOPODIOPHYTA
¢ Lycophyll ¢ Stem Exarch ¢ Root Endarch
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Lepidodendron
EXTINCT LYCOPODS WERE TALL TREES: MAKE UP SOME OF COAL DEPOSITS
LYCOPODS ALIVE TODAY ARE SMALL - ALL HAVE LYCOPHYLLS / MICROPHYLL - (1 VEIN, INTERCALARY MERISTEM)
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EXTANT LYCOPHYTES
¢ Lycopodiaceae = club mosses ¢ Sellaginellaceae = spike moss ¢ Isoetaceae
� monotypic
Sporophylls- contain sporangium
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Lycopodiaceae ¢ Homosporous
Selaginellaceae and Isoetaceae ¢ Heterosporous ¢ Leaf ligules ¢ Endosporic
� Gametophyte develops within the original spore wall
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Lycopodium clavatum
Lycopodium lucidulum
Lycopodium digitatum Lycopodium squarrosum
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SELAGINELLACEAE
¢ Leaves are isomorphic or dimorphic (Selaginella)
“ligulate” lycophytes - heterosporous
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SOME LYCOPODS HAVE DIMORPHIC LEAVES
Selaginella apoda
2 rows large leaves
Selaginella apoda
2 rows small leaves
Some Lycopods
have dimorphic
leaves
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HETEROSPORY ¢ Microspores- microsporangium
� numerous; relatively smaller
¢ Megaspores- megasporangium � Fewer; relatively larger
“ligulate” lycophytes - heterosporous
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Selaginella spp.
Selaginella cinerascens
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Lycopods Isoetes Merlin’s Grass
Isoetaceae - Acicular leaves -shallow aquatics
Isoetes orcuttii
Isoetes howellii
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EUPHYLOPHYTES
¢ Exarch protoxylem ¢ Euphylls/ megaphyll
- apical meristem derived; associated leaf gap
¢ cp DNA inversion A. Monilophytes (ferns s.l.) B. Seed plants
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EQUISETOPHYTES (EQUISETUM) - SCOURING RUSHES / HORSETAILS
¢ Have ridged stems
¢ Whorled microphylls
¢ Silica in cell walls
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Equisetum hyemale Common Scouring-Rush
Equisetum laevigatum Smooth Scouring-Rush
Whorled microphylls
Cone (strobilus)
Equisetum arvense Common Horsetail
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PSILOPSIDS - E.G., PSILOTUM NUDUM WHISK BROOM
¢ Microphylls or enations (no veins)
¢ Dichotomously branched, green stems
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Psilotum nudum
dichotomous branching
Psilotum nudum
enations
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Psilotum nudum
synangium
bifurcate (“forked”) appendage
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MARATTIALES- POLYCYCLIC SIPHONOSTELE
Marattia Eusporangia
- Relatively large; derived from several epidermal cells; sporangial wall surrounded by many layers of cell
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Ophioglossaceae Ophioglossum californicum Calif. Adder’s
Tongue
fertile
sterile
LEPTOSPORANGIATE FERNS = POLYPODIALES
Leptosporangium:
- Develops from one cell
- one cell thick
- spores ejected
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spor ophyte(2n)
gametophyte(n)
youngspor ophyte(2n)
sperm cell(n)
egg cell(n)
archegoniumantheridium
spore(n)
rhizomesori
leptosporangium
gametophyte(n)
annulus
spores(n)
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frond
stipe
pinna
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antheridium
archegonium
egg
sperm
Fern leaf development
fiddle head/ crozier
Circinnate vernation= shared with Marattiales and cycads
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Nephrolepis
Adiantum
Lygodium Climbing Fern - a vine
Cyathium a tree fern
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Coastal Wood Fern
indusium covering
sorus
California Polypody
sorus -group of
leptosporangia
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Adiantum reniformis California Maidenhair Fern
Platycerium Staghorn Fern
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Aquatic ferns
Marsilea Salvinia Azolla
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Azolla Mosquito Fern - symbiotic relationship with blue green bacteria - “seeded” in rice paddies for nitrogen fixation