Seedless Plants Slides PDF

BIOL 1108K Lab: Seedless Plants Seedless plant origins Part I: Alternation of Generations and Lifecycle Notes Generalized Alteration of Generation present in land plants Haploid multicellular organism (gametophyte) Mitosis...

BIOL 1108K Lab: Seedless Plants Seedless plant origins Part I: Alternation of Generations and Lifecycle Notes Generalized Alteration of Generation present in land plants Haploid multicellular organism (gametophyte) Mitosis Mitosis Spores Gametes MEIOSIS FERTILIZATION Zygote Mitosis Diploid multicellular organism (sporophyte) Alternation of generations in a moss Sperm Antheridia Key Male gametophyte Haploid (n) (n) MITOSIS MITOSIS Diploid (2n) Egg Spores Gametophore Spore Archegonia dispersal Female gametophyte (n) Rhizoid Sporangium FERTILIZATION Seta Zygote (within archegonium) MEIOSIS Capsule (2n) Mature sporophytes (sporangium) Foot Embryo Archegonium Young 2 mm sporophyte MITOSIS (2n) Female gametophytes Figure 29.12 Alternation of generations in a fern MITOSIS Haploid (n) Diploid (2n) Spore Young Antheridium Spore (n) gametophyte MEIOSIS dispersal Rhizoid Sporangium Sperm Underside of mature gametophyte Archegonium MITOSIS Mature (n) Egg sporophyte New Sporangium (2n) sporophyte Zygote FERTILIZATION Sorus (2n) MITOSIS Gametophyte Fiddlehead (young leaf) © 2017 Pearson Education, Inc. Part II: Nonvascular plants Nonvascular plants Gametophytes are dominant generation No vascular tissue; no true tissues, leaves or roots ○ Rhizoids Small in size Dependent on water Bryophyta Mosses large group; 15,000 species setae & stomata present survive in diverse habitats Sphagnum Longitudinal section of mature moss capsule Hepatophyta Liverworts large group; 9,000 species setae present; stomata absent tiny sporophytes Plagiochila deltoidea, a “leafy” liverwort Conocephalum conicum (greater scented liverwort) Marchantia, a “thalloid” liverwort Microscopic cross section of a Marchantia sporophyte Anthocerophyta Hornworts small group; 100 species stomata present; setae absent symbiosis with nitrogen-fixing cyanobacteria ex) Nostoc Microscopic longitudinal section of Anthoceros sporophyte Part III: Vascular Seedless Plants Seedless vascular plants Sporophytes are dominant generation Well developed vascular tissue; true tissues, leaves and roots ○ xylem & phloem Sporophylls – leaves that bear sporangia  Seedless vascular plants - homosporous – 1 type of sporangium producing one type of spore - heterosporous – 2 types of sporangia producing 2 types of spores - megaspore – develop into female gametophyte - microspore – develop into male gametophyte Homosporous spore production Eggs (*most seedless Typically a Sporangium Single bisexual vascular plants) on sporophyll type of spore gametophyte Sperm Heterosporous spore production Female (*all Megasporangium gametophyte Eggs Megaspore seeded on megasporophyll plants) Microsporangium Microspore Male Sperm on microsporophyll gametophyte Lycophyta Club mosses, spike mosses, quillworts 1200 species Club mosses are Selaginella moellendorffii, Isoetes gunnii, a quillwort homosporous a spike moss Spike mosses & quillworts are Strobili heterosporous (clusters of sporophylls) In some species, sporophylls are clustered into club-shaped cone called a strobilus Diphasiastrum tristachyum, a club moss  Club mosses Foxtail club moss Shining club moss Running pine Life cycle of Selaginella, a spike moss Microscopic longitudinal sections of Selaginella strobilus Monilophyta Ferns, horsetails, whisk ferns 12,000 species Most species are homosporous Ferns – most widespread of group ○ possess megaphylls Horsetails – jointed plants” ○ - small rings of leaves or branches encircle stem Whisk ferns - “living fossils” ○ - lack true roots & stems ○ - mainly tropical epiphytes Psilotum, a whisk fern Microscopic cross section of Psilotum sporangium Microscopic cross section of Psilotum aerial stem phloem xylem Life cycle of Equisetum, a horsetail Microscopic longitudinal section of Equisetum strobilus Ferns Christmas fern Cinnamon fern Interrupted fern Circinate vernation pattern of leaf development  Fern sori Cross section of sporangium Cross section of sorus Fern gametophyte (prothallus) Fern gametophyte (under dissecting scope) Fern gametophyte and immature sporophyte (under dissecting scope)