Angiosperms 1 Bio 1B Fall 06 Professor Thomas Carlson tcarlson berkeley edu 11 11 03 Bryophytes Pteridophytes Alternation of Generations X X Haploid Dominant X X Sporophyte dependent on gametophyte Water required for fertilization X Diploid Dominant Tracheids or vessels Gametophyte dependent on sporophyte Wind or animal fertilization Pollen Seeds Flowers Fruits Double Fertilization Triploid Endosperm X 2 3 4 Angiosperms X X X Independent sporophyte gametophyte Heterosporous Gymnosperms 1 X X X tracheids Aquatic ferns X X tracheids vessels X X vessels tracheids X X X X X mainly wind X X X animals wind X X X X 5 6 7 9 8 10 11 ANGIOSPERM LIFE CYCLE Fig 30 10 Flowering Plant Flowering Plant Flower Flower Carpel megasporophyll Stamen microsporophyll Ovule megasporangium Anther with 4 chambers 4 microsporangia Megasporocyte Mother cell Diploid precursor cell Microsporocyte Father cell Diploid precursor cell Megaspore Microspore Megagametophyte 7 cells with 8 nuclei Microgametophyte 3 celled pollen grain Egg with 2 synergid cells near micropyle Two polar nuclei cell Generative cell in pollen grain tube Egg ovum Sperm 12 Angiosperms enclosed seed Importance of flowering plants Pollen Double fertilization Triploid endosperm Ovules in flowers enclosed by carpel Seeds in fruits enclosed by carpel Xylem contains vessel elements fibers Phloem contains companion cells Complex leaves Most species rich group of plants at least 250 000 Source of most human food Rice wheat and corn are fruits of angiosperms 13 14 Gymnosperm naked seed Diversity in angiosperms Figs 30 3 30 6 Gymnosperm ovules are naked exposed to air when the ovuliferous scales of conifers separate to let pollen in Eucalyptus trees 100s of feet tall Aquatic duckweed 1 mm in diameter Angiosperms enclosed seed Epiphytes Fig 30 10 38 7 38 8 38 9 Ovules surrounded by sporophytic tissues which create a barrier to outside world Sperm reach eggs via pollen tubes growing through parental sporophyte tissue Non photosynthetic parasites Insectivorous plants 15 Angiosperms Double fertilization Fig 30 10 38 6 Campbell One sperm fertilizes egg to form zygote Other sperm joins with two nuclei in the megagametophyte to form triploid 3n tissue called endosperm The triploid endosperm becomes the source of nutrients for the developing embryo 17 16 18 Major Angiosperm Clades Fig 30 12 Judd et al 2002 Basal Families pollen usually monocolpate usually have monocolpate pollen grains with single long grooved aperture some lack vessels or have primitive vessels Magnoliid Complex Monocots monocolpate pollen Eudicots tricolpate pollen tricolpate pollen grains have 3 long grooved apertures each with a central pore 19 Primitive Angiosperm Clades Fig 30 12 Basal Families earliest flowering plants pollen usually monocolpate with one furrow or pore Amborellaceae 1 species in New Caledonia it lacks vessels Nymphaeaceae water lilies lacking or with primitive vessels Illiciaceae e g star anise Illicium verum is source of the Tamiflu drug to treat avian influenza Magnoliid Complex select families listed below Magnoliaceae magnolias Lauraceae cinnamon camphor California bay laurel Piperaceae black pepper kava betel leaf 21 20 22 Monocots 23 Monocots Fig 30 12 Examples of monocot families Usually monocolpate pollen has one furrow or pore Liliaceae lilies Floral parts usually in multiples of 3s Leaf venation is usually parallel One cotyledon in embryo Zingiberaceae gingers Dioscoreaceae yams cotyledon small leaf of plant embryo that stores nutrients and can be photosynthetic First root in cotelydon is short lived Arecaceae palms e g coconut betel nut Stems with scattered vascular bundles no secondary growth Poaceae grasses e g rice wheat corn Orchidaceae orchids vanilla 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 Eudicots 67 68 Examples of Eudicot families Examples of Eudicot families Ranunculaceae basal eudicot family buttercups goldenseal Papaveraceae morphine codeine from opium poppy Caryophyllaceae carnations Vitaceae grapes Fabaceae beans peas Brassicaceae kale cabbage brussel sprouts broccoli cauliflower 69 Rosaceae roses apples pears peaches almonds strawberries raspberries Cucurbitaceae pumpkins squash cucumbers Solanaceae tomato potato eggplant chili pepper atropine from Atropa belladonna Lamiaceae peppermint spearmint catnip basil sage rosemary thyme Apiaceae carrots anise celery fennel Asteraceae sunflowers Echinacea Calendula 70 EUDICOTS Fig 30 12 Tricolpate pollen Floral parts usually in multiples of 4 or 5 Leaf venation is reticulate or netlike Two cotyledons in embryo Stems with vascular bundles in circular pattern with secondary growth First root of dicot embryo is long lived develops into taproot system 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 Angiosperms Flower contributes centrally to the development of the diversity in this group Flowers Adaptations that enhance pollination Tremendously diverse in size shape color fragrance 103 104 Flower Structure Fig 30 7 30 12 30 13 38 2 38 3 Unit for sexual reproduction in angiosperms Developed from shoots that have been modified for reproduction 105 106 Flower Parts Figs 30 7 30 12 30 13 38 2 38 3 Pedicel stalk of flower Recepticle portion of pedicel to which floral parts are attached Four kinds of floral appendages arranged in series of whorls Sepals outer lowest on axis usually green Petals often large colorful to attract pollinators Stamens male Carpels female inner highest on axis 107 108 Floral appendages Floral appendages Fig 30 7 30 12 30 13 38 2 38 3 Fig 30 7 30 10 38 4 Sepals collectively the calyx outer most lowest appendage usually green Stamens microsporophylls male structures that consist of Petals collectively the corolla large and often non green bright colors base of petal may contain a nectary which produces the sugar rich nectar filament supporting stalk four chambered anther in which pollen is produced Perianth collectively made up of sepals petals each chamber in anther is equivalent to a microsporangium 109 110 Male Gametophyte Production Fig 30 7 30 10 38 4 Anther chambers microsporangia are lined with the tapetum which is a layer of cells that supplies nutrients to the developing pollen grains Shortly before pollen is released the tapetum breaks down and covers pollen with proteins Proteins on the pollen grains 111 can cause hay fever allow stigma
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