1Angiosperms #1Bio 1B Fall ’07Professor: Thomas Carlson2345XXXDiploid DominantXXGametophytedependent onsporophyteX animals & windX mainly windPollinationXX GnetophytesVesselsXXXTracheidsXDouble fertilization &Triploid EndospermXXAntheridiumXXXArchegoniumXFlowers/FruitsXXSeedsXXPollenXX X Aquatic fernsXHeterosporousXIndependentsporophyte &gametophyteXXWater required forfertilizationXSporophytedependent ongametophyteXHaploid DominantX XXXAlternation ofGenerationsAngiospermsGymnospermsPteridophytesBryophytestcarlson@berkeley.edu8/28/076789101112ANGIOSPERM LIFE CYCLE (Fig 30.10) Flowering Plant Flower Carpel (megasporophyll) Ovule (megasporangium) Megasporocyte = Mother cell = Diploid precursor cell Megaspore Megagametophyte (7 cells with 8 nuclei) Egg with 2 synergid cells near micropyle Two polar nuclei cell Egg (ovum) Flowering Plant Flower Stamen (microsporophyll) Anther with 4 chambers (4 microsporangia) Microsporocyte = Father cell = Diploid precursor cell Microspore Microgametophyte (2 celled pollen grain with 1 vegetative cell & 1 generative cell) Pollen tube develops from vegetative cell & 2 sperm develop from generative cell Sperm13Angiosperms (enclosed seed)• 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 leaves14Importance of flowering plants• Most species rich group of plants(at least 250,000)• Source of most human food• Rice, wheat, and cornare fruits of angiosperms15Diversity in angiosperms• Eucalyptus trees 100s of feet tall• Aquatic duckweed 1 mm in diameter• Epiphytes• Non-photosynthetic parasites• Insectivorous plants16Gymnosperm (naked seed)(Figs 30.3, 30.6)• Gymnosperm ovules are naked & exposed to airwhen the ovuliferous scales of conifers separate tolet pollen inAngiosperms (enclosed seed)(Fig 30.10, 38.7, 38.8, 38.9)• Ovules surrounded by sporophytic tissues whichcreate a barrier to outside world• Sperm reach eggs via pollen tubes growingthrough parental sporophyte tissue17AngiospermsDouble fertilization (Fig 30.10, 38.6 Campbell)• One sperm fertilizes egg to form zygote• Other sperm joins with two nuclei in themegagametophyte to form triploid (3n) tissuecalled endosperm• The triploid endosperm becomes the source ofnutrients for the developing embryo1819Major Angiosperm Clades(Fig 30.12) (Judd et al., 2002)• Basal Families (pollen usually monocolpate)– usually have monocolpate pollen grains with singlelong 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)2021Primitive 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 lacksvessels)– Nymphaeaceae (water lilies, lacking or with primitivevessels)– Illiciaceae (e.g., star anise, Illicium verum is source ofthe 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)222324Monocots25Examples of monocot families• Liliaceae (lilies)• Zingiberaceae (gingers)• Dioscoreaceae (yams)• Arecaceae (palms e.g., coconut, betel nut)• Poaceae (grasses e.g., rice, wheat, corn)• Orchidaceae (orchids, vanilla)26Monocots (Fig 30.12)Usually monocolpate pollen (has one furrow or pore)• Floral parts usually in multiples of 3s• Leaf venation is usually parallel• One cotyledon in embryo(cotyledon = small leaf of plant embryo that stores nutrientsand can be photosynthetic)– First root in cotelydon is short lived• Stems with scattered vascular bundles& no secondary growth272829303132333435363738394041424344454647484950515253545556575859606162636465666768Eudicots69• Ranunculaceae {basal eudicot family}(buttercups, goldenseal)• Papaveraceae (morphine & codeine from opiumpoppy)• Caryophyllaceae (carnations)• Vitaceae (grapes)• Fabaceae (beans, peas)• Brassicaceae(kale, cabbage, brussel sprouts, broccoli,cauliflower)Examples of Eudicot families70Examples of Eudicot families• Rosaceae(roses, apples, pears, peaches, almonds,strawberries, raspberries)• Cucurbitaceae (pumpkins, squash, cucumbers)• Solanaceae (tomato, potato, eggplant, chilipepper, atropine from Atropa belladonna)• Lamiaceae(peppermint, spearmint, catnip, basil…sage,rosemary & thyme)• Apiaceae (carrots, anise, celery, fennel)• Asteraceae (sunflowers, Echinacea, Calendula)71EUDICOTS (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 circularpattern with secondary growth• First root of dicot embryo is long-lived &develops into taproot system72737475767778798081828384858687888990919293949596979899100101102CactaceaeFlower Morphology103104105Angiosperms• Flower contributes centrally to the development ofthe diversity in this groupFlowers• Adaptations that enhance pollination• Tremendously diverse in size, shape, color,fragrance106Flower Structure(Fig 30.7, 30.12, 30.13, 38.2, 38.3)Unit for sexual reproduction in angiospermsDeveloped from shoots that have beenmodified for reproduction107108Flower Parts(Figs 30.7, 30.12, 30.13, 38.2, 38.3)• Pedicel = stalk of flower• Recepticle = portion of pedicel to which floralparts are attached• Four kinds of floral appendagesarranged in series of whorls:Sepals: outer & lowest on axis; usually greenPetals: often large & colorful to attract pollinatorsStamens: maleCarpels: female (inner & highest on axis)109110Floral appendages(Fig 30.7, 30.12, 30.13, 38.2, 38.3)• Sepals (collectively the calyx):outer most, lowest appendage, usually green• Petals (collectively the corolla):large and often non-green bright colors(base of petal may contain a nectary whichproduces the sugar-rich nectar)• Perianth: collectively made up of sepals &petals111Floral appendages(Fig 30.7, 30.10, 38.4)• Stamens = microsporophylls/male structuresthat consist of:– filament (supporting stalk)– four-chambered anther in which pollen is produced– each chamber in anther is equivalent
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