Bis2CF10.Lecture19

Bis2CF10.Lecture19 - Lecture 19 GYMNOSPERMOUS SEED PLANTS...

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Unformatted text preview: Lecture 19 GYMNOSPERMOUS SEED PLANTS Last: ferns, origin & basic features of seed plants Cycads: primitive seed plant reproduction Conifers and Ginkgo Gnetophytes Next: origin of angiosperms, place in seed plants Stomata Lycophyta Overtopping Psilophyton Stomata Lycophyta Overtopping Secondary growth Archaeopteris: Late Devonian “progymnosperm” fertile appendages secondary xylem Branch system with dichotomously veined simple leaves Pollen with male gametophyte (microgametophyte) Ancestral seed plant life cycle micropyle megaspore integument megasporangium primary root embryo female gametophyte cotyledons OVULE female gametophyte (megagametophyte) archegonium with egg MATURE SEED Carboniferous “seed ferns” Lyginopteris compound leaf woody trunk Medullosa Carboniferous “seed ferns” Lyginopteris compound leaf Free integument lobes Early Carboniferous seeds, Scotland (Long 1959-1961) Carboniferous “seed ferns” Lyginopteris compound leaf Archaeopteris Late Devonian “progymnosperm” Branch system with simple leaves Callistophyton Carboniferous “seed fern” axillary bud, with bud scales axillary branch bud scale Lycophytes Euphyllophytes Pteridophytes Seed plants Pine Fern Lycopodium leptoaxillary sporangia sporangia microphylls roots Psilotum loss of roots reduced leaves cylindrical gpts fernlike leaves? Ophio. reduced leaves whorled leaves “progymnosperms” multiflagellate sperm overtopping roots axillary branching seeds compound leaves Equisetum Zosterophyllum lateral sporangia Aglaophyton typical tracheids branched sporophyte vascular tissue secondary growth (2o xylem, phloem, & periderm = Heterospory (naked seeds) (also no flowers) Secondary growth Net-veined leaves 2+2 microsporangia Carpel: ovules enclosed Two integuments Reduced gametophytes Double fertilization CARPEL seeds enclosed Elkinsia Lyginopteris Medullosans Taxaceae Cephalotaxus Taxodiaceae Araucariac Podocarpac CONIFERS GNET Medullosan seed fern (Carboniferous) Doyle 2008 Status 8 steps Dollo Pinaceae Ephedra Welwitschia Gnetum Emporia Ginkgoales Cordaitales Corystosperms Autunia Peltaspermum Callistophyton Cycadales Glossopterids Pentoxylon Bennettitales Caytonia Amborella Nymphaeales Hydatellaceae Schisandrac Illicium Trimenia Austrobaileya Chloranthac ANGIOSPERMS Morphology with molecular backbone One of 18 trees fossil living fossil living “seed ferns” Winteraceae Asaroideae Saururaceae Encephalartos Zamia Cycads CYCADS microsporophyll Cycas Megasporophyll with ovules/seeds broken female cone MALE CONE = microsporangiate Zamia Cycad seeds, male gametophytes & motile sperm = megasporangium female gpt pollen tubes integument male gametophytes female gpt egg Cycad seeds, male gametophytes & motile sperm = megasporangium female gpt pollen tubes integument male gametophytes Monosulcate pollen Single furrow for pollen tube germination female gpt egg Cycad seeds, male gametophytes & motile sperm = megasporangium female gpt pollen tubes integument male gametophytes female gpt multiflagellate sperm egg Simple, one-veined leaves Conifers (Pinus) Early Permian conifer Carboniferous coal swamp Northernmost spruce forest (Picea), Alaska Sequoia Sequoiadendron Pinus longaeva Conifers (Pinaceae): male & female cones (strobili) Pinus cone scale bract = modified leaf female cone Pollen with air sacs seed male cones Pseudotsuga: protruding bracts Female cone = compound strobilus (stem with leaves, fertile branches) Male cone = simple strobilus (stem with sporophylls) Permian conifers female cone sporophyll scale leaf bract male cones Bract and axillary fertile shoot Seed with dormant embryo Conifers: pollen tube transfers nonmotile sperm to egg integument Pine pollen in pollen chamber megasporangium pollen tube egg micropyle apex of megasporangium female gametophyte integument DIVERSITY IN CONIFERS Cupressaceae Juniperus Taxaceae Taxus (yew) Araucariaceae: Araucaria (Chile) Simple leaf dichotomous veins Ginkgo biloba female strobili Ginkgo biloba seeds male strobili motile sperm female strobili Ginkgo biloba Baiera: Jurassic ginkgophyte male strobili Elkinsia Lyginopteris Medullosans Taxaceae Cephalotaxus Cupressaceae Araucariaceae Podocarpaceae COMP > SIMPLE CONIFERS GNET Carboniferous seed fern COMPOUND LEAVES Pinaceae Ephedra Welwitschia Gnetum Emporia Ginkgoales Cordaitales Corystosperms Morphology with molecular backbone Doyle 2008 Autunia Peltaspermum Callistophyton Cycadales Glossopterids Pentoxylon Bennettitales Caytonia Amborella Nymphaeales Hydatellaceae Schisandraceae Illicium Trimenia Austrobaileya Chloranthaceae palmate Leaf type Reconstruction 2 10 steps unordered uncertain one veined dichotomous simple pinnate pinn compound ANGIOSPERMS Winteraceae Asaroideae Saururaceae Simple leaves = Heterospory Nonmotile sperm naked seeds (also no flowers) Secondary growth Net-veined leaves 2+2 microsporangia Carpel: ovules enclosed Two integuments Reduced gametophytes Double fertilization carpel seeds enclosed Gnetophytes Ephedra GNETOPHYTES opposite leaves Ephedra Gnetum GNETOPHYTES Welwitschia (Namib Desert, SW Africa) V Ephedra wood with vessels Conifer wood with tracheids V vessel elements with perforations Ephedra wood with vessels Ephedra male female outer “integument” microsporophylls ovule inner integument scale leaf Simple leaves = Heterospory Nonmotile sperm naked seeds (also no flowers) Opposite leaves Vessels Secondary growth Net-veined leaves 2+2 microsporangia Carpel: ovules enclosed Two integuments Reduced gametophytes Double fertilization carpel seeds enclosed ...
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This note was uploaded on 04/19/2011 for the course BIOLOGY BIS 2C taught by Professor Doyle during the Fall '10 term at UC Davis.

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