Conifers BIOL 1407. Seed Plants Vascular Tissue Produce seeds –Dispersal of offspring Produce pollen Sperm transfer without water

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  • ConifersBIOL 1407

  • Seed PlantsVascular TissueProduce seedsDispersal of offspringProduce pollenSperm transfer without water

  • Seed PlantsSporophyte dominantGametophytesGreatly reduced in sizeDependent on sporophyte

  • Seed PlantsHeterosporousMegasporeGrows into female gametophyte eggsMicrosporeGrows into male gametophyte spermPhoto Credit for Ovulate Cone: Dr. Stephen Bostic, ACCCircled area: Ovule

  • Pollen ProductionPollen cones have microsporophyllsEach microsporophyll has microsporangiaPhoto Credit for Immature Male Pine Cones: Menchi, Wikimedia Commons

  • Pollen ProductionMeiosis occurs within microsporangia microsporesPhoto Credit for Staminate Cone: Dr. Stephen Bostic, ACCMicrosporangium circled in redMicrosporophyll at tip of yellow pointerMicrospores circled in pink

  • Pollen ProductionMicrospores grow into male gametophytesMale gametophyte = pollen grain

  • PollinationPollen is released Travels from male to femalePollination occurs when pollen grain lands on female

  • Pollen GerminationAfter landing pollen coat breaks open1 cell produces pollen tubePhoto Credit: Dr. David Byres, Florida Community College at Jacksonville

  • Pollen GerminationA different cell produces 2 sperm cells by mitosisThey will move down pollen tube as it growsPhoto Credit: Dr. David Byres, Florida Community College at Jacksonville

  • Pollen GerminationPollen tube digests its way through female tissues to reach the egg

  • OvulesOvulate cones have megasporophyllsEach megasporophyll has ovules containing megasporangiaPhoto Credit for Immature Female Ponderosa Pine Cones: Susan McDougall @ USDA-NRCS PLANTS Database

  • OvulesMeiosis occurs within megasporangium forms 1 megaspore and 3 haploid nuclei (degenerate)Photo Credit: Dr. Stephen Bostic, ACCMegasporangium circled in redMegasporophyll at tip of yellow pointer

  • OvulesMegaspore grows into female gametophyteFemale gametophyte makes 1-2 eggs by mitosis

  • OvulesInteguments surround female gametophyteMicropyle lets pollen reach female gametophyte

  • Ovules SeedsInteguments seed coatFemale gametophyte food supplyFertilized egg embryo

  • SeedsDispersed by:WindAnimalsWaterMechanicalPhoto Credit for Pitch Pine Seeds: Steve Hurst @ USDA-NRCS PLANTS Database

  • Types of Seed PlantsGymnospermsNaked SeedsNot enclosed in ovariesNo fruits or flowers

  • Types of Seed PlantsAngiospermsFlowering PlantsSeeds enclosed in ovariesFruits and flowers

  • Modern GymnospermsConifersOldest living plantsLargest living plantsWidespreadReproductive structure: Cones

  • Modern GymnospermsCycadsWiry leavesSago palmsGinkgosDeciduous treesOne speciesHerbal supplement

  • Modern GymnospermsGnetophytesEphedra (Mormon tea)Welwitschia

  • The EndUnless otherwise specified, all images in this presentation came from:Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.