introduction to botany. lecture 30 -...
TRANSCRIPT
Introduction to Botany. Lecture 30
Alexey Shipunov
Minot State University
November 17, 2017
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Outline
1 Questions and answersQuiz
2 Phylum PteridophytaClassis Equsetopsida, horsetailsHeterosporyMore “ferny” ferns
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Outline
1 Questions and answersQuiz
2 Phylum PteridophytaClassis Equsetopsida, horsetailsHeterosporyMore “ferny” ferns
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Questions and answers Quiz
Questions and answersQuiz
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Questions and answers Quiz
Final question (3 points)
Why are mosses “evolutionary dead end”?
Their (parazitic) sporophyte “interests” conflict with gametophyte“interests”.
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Questions and answers Quiz
Final question (3 points)
Why are mosses “evolutionary dead end”?
Their (parazitic) sporophyte “interests” conflict with gametophyte“interests”.
Shipunov (MSU) Introduction to Botany. Lecture 30 November 17, 2017 4 / 35
Phylum Pteridophyta
Pteridophyta classes
Subphylum Lycopodiophytina (lycophytes)[Microphyllous]
Class Lycopodiopsida
Subphylum Pteridophytina (monilophytes)[Megaphyllous]
Class Equisetopsida (horsetails)Class Psilotopsida (whisk ferns)Class Ophioglossopsida (ophioglossalean ferns)Class Marattiopsida (giant, or marattialean ferns)Class Pteridopsida (“true” ferns)
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Phylum PteridophytaClassis Equsetopsida, horsetails
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Equisetopsida
Small group of one genus, Equisetum with ≈ 30 speciesLeaves are reduced into scales, stems are segmented,photosynthetic. Have specific stele—artrostele with specificcentral and peripheral canals (similar to stele of some grasses)Sporangia associated with specialized leaves—sporangiophores.Spores have attached elaters. Gametophyte minute, usuallydioecious but plants are homosporous
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Strobili and sporangiophores of Equisetum arvense
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Equisetum giganteum
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Equisetum sp. elaters
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Artrostele
(please ignore labels)
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Phylum Pteridophyta Classis Equsetopsida, horsetails
Horsetail gametophytes
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Phylum Pteridophyta Heterospory
Phylum PteridophytaHeterospory
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Phylum Pteridophyta Heterospory
Horsetails start it: spores same, gametophytesdifferent
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Phylum Pteridophyta Heterospory
Heterosporic cycle: differences
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Phylum Pteridophyta Heterospory
Heterospory
Heterosporous ferns (lycophytes Selaginella and Isoëtes,monilophytes Salvinia, Marsilea, Pilularia, Regnellidium and Azolla)went one step further and made their spores different too. It will allowthe better allocation of resources and will restrict the self-fertilization.
Terms covered:
Male gametophyte, female gametophyteMicrospores and microsporangiumMegaspores and megasporangium
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Phylum Pteridophyta Heterospory
Life cycle of land plants
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Phylum Pteridophyta Heterospory
Heterosporic cycle: differences
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Phylum Pteridophyta More “ferny” ferns
Phylum PteridophytaMore “ferny” ferns
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Phylum Pteridophyta More “ferny” ferns
Psilotopsida
Small tropical group of two genera, Psilotum and Tmesipteris and7 speciesHave protostele (like lycophytes), underground long-livedgametophytes but multiflagellate spermatozoa (like horsetails andall “higher” ferns). Sporangia unite into synangia. Leaves mayabsent (Psilotum) and replaced with enatia.Externally remain fossil rhyniophytes, the oldest extinctPteridophyta
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Phylum Pteridophyta More “ferny” ferns
Hawaiian Psilotum complanatum
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Phylum Pteridophyta More “ferny” ferns
New Zealand Tmesipteris tannensis with doublesynangium
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Phylum Pteridophyta More “ferny” ferns
Ophioglossopsida
Small group (Ophioglossum, Botrychium, Mankyua andHelminthostachys) and ≈ 75 speciesAlways have underground rhizome and aboveground bisectedleaves: one half is the leaf blade and other half issporangiophore. Gametophytes grow underground.Some (namely, Botrychium, grape fern) have secondarythickening of underground rhizome.Ophioglossum vulgatum, adder’s tongue fern, has 2n = 1360, thelargest chromosome number ever.
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Phylum Pteridophyta More “ferny” ferns
Ophiloglossum vulgatum, 2n = 1360 hero
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Phylum Pteridophyta More “ferny” ferns
Helminthostachys zeylanicum (Ophioglossopsida)
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Phylum Pteridophyta More “ferny” ferns
Mankyua chejuense (Ophioglossopsida)
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Phylum Pteridophyta More “ferny” ferns
Marattiopsida
Tropical ferns, several genera with ≈ 100 speciesBiggest ferns, one leaf (frond) could be 6 m length, but stems aresmaller. Leaves with stipules.Sporangia (eusporangia like in all other Pteridophyta except“true” ferns) usually unite in synangia, gametophytes 1-2 cm indiameter, photosynthetic, terrestrial, usually long-lived.In a past, also were dominants of Carboniferous swamp forests.
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Phylum Pteridophyta More “ferny” ferns
Angiopteris sp. (Marattiopsida)
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Phylum Pteridophyta More “ferny” ferns
Synangia of Danaea nodosa (Marattiopsida)
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Phylum Pteridophyta More “ferny” ferns
Pteridopsida
“True” ferns, about 10,000 species.Leaves are fronds, with apical growth. Young leaves are coiled infiddleheads.Sporangia have one-celled wall (leptosporangia) and grouped insori (often covered with indusium)Gametophyte minute, grow aboveground. Some genera of fernsare heterosporous.Bracken fern, Pteridium acquilinum, is the most widespread plantof the world.Many ferns have various vegetative reproduction.
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Phylum Pteridophyta More “ferny” ferns
Sorus, indusium, leptosporangium and annulus
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Phylum Pteridophyta More “ferny” ferns
Heterosporous fern Marsilea quadrifolia,the Shamrock. Well, almost...
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Phylum Pteridophyta More “ferny” ferns
Young leaves of bracken fern: Korean “gosari”
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Phylum Pteridophyta More “ferny” ferns
Final question (3 points)
Why heterospory “is better”?
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Phylum Pteridophyta More “ferny” ferns
Final question (3 points)
Why heterospory “is better”?
Shipunov (MSU) Introduction to Botany. Lecture 30 November 17, 2017 34 / 35
Phylum Pteridophyta More “ferny” ferns
For Further Reading
A. Shipunov.Introduction to Botany [Electronic resource].Mode of access:http://ashipunov.info/shipunov/school/biol_154
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