BIO 1010 Ch. 25 & 9 - Angiosperms, Flowers, Fruits & Seeds FA23 PDF

Chapter 25: Angiosperms Chapter 25 Learning Objectives ❖ Summarize the features that distinguish flowering plants from gymnosperms ❖ Describe the ecological and economic significance of flowering plants. ❖ Distinguish between monocots and eudicots. Be able to give examples of each. ❖ Discuss some ev...

Chapter 25: Angiosperms Chapter 25 Learning Objectives ❖ Summarize the features that distinguish flowering plants from gymnosperms ❖ Describe the ecological and economic significance of flowering plants. ❖ Distinguish between monocots and eudicots. Be able to give examples of each. ❖ Discuss some evolutionary adaptations of flowering plants. ❖ Distinguish between basal angiosperms and core angiosperms. ❖ Briefly describe and distinguishing characteristics of the following flowering plant families. Be able to give plant examples from each. BIO 1010 Chapter 9: Flowers, Fruits, and Seeds Chapter 9 Learning Objectives ❖ Name the parts of a flower and describe the functions of each part. ❖ Distinguish between pollination and fertilization. ❖ Compare the general characteristics of flowers pollinated in different ways. ❖ Define coevolution and give examples of way in which plants and their animal pollinators have affected one another’s evolution. ❖ List and define the main parts of a seed. ❖ Distinguish among simple, aggregate, multiple and accessory fruits; give examples of each type and cite several different methods of seed and fruit dispersal. ❖ Summarize the influence of environmental factors on seed germination. Angiosperms – The Flowering Plants ❖ Phylum Anthophyta (Magnoliophyta): Flowering Plants ❖ Largest Phylum ❖ Heterosporous ❖ Sporophytes dominant and independent Female gametophytes wholly enclosed within and dependent on sporophyte Microspores are released to become mature male gametophytes following pollination. Important Adaptations Basal Angiosperms Proposed Plant Evolution Basal Angiosperms ❖ Amborella trichopoda 2nd oldest group – water lilies 3rd oldest group – star anise Magnoliids Monocotyledones (Monocots) Eudicotyledones (Eudicots) Differences Between Eudicots and Monocots Eudicots Monocots Two cotyledons One cotyledon Flower parts in multiples of four or five Flower parts in multiples of three Leaves with distinct network of veins Leaves with parallel primary veins Vascular cambium and cork cambium present Vascular cambium and cork cambium absent Vascular bundles of stem in ring Vascular bundles of stem scattered Pollen grains with three apertures Pollen grains with one aperture Monocots and Eudicots 15 Generalized Flower Morphology (b) Cutaway view of an Arabidopsis flower. Each flower has four sepals (two are shown), four petals (two are shown), six stamens, and one pistil. Fig. 9-1b, p. 177 Generalized Flower Morphology (Whorls) pistil 18 ❖ Seeds enclosed in carpel that resembles a leaf that has folded over and fused at the margins. Pistil composed of a single carpel, or two or more united carpels. ❖ Seed develops from ovule within carpel and ovary becomes a fruit. Development of the Female Gametophyte Development of the Female Gametophyte Development of the Male Gametophyte Anther with microspores Development of the Male Gametophyte Colorized SEM Angiosperm Pollen Grains Angiosperms – The Flowering Plants Mature male gametophyte = germinated pollen grain with its vegetative nucleus and two sperms within tube cell (a) Development of a male gametophyte (in pol l en grain) (b) Development of a female gametophyte (embryo sac) Microsporangiu (pollen sac) Megasporangium (211) Microsporocyte (2n)......- Integuments (2n) MEIOSIS 1. 4 microspores (n) Megasporocyte (211) Micropyle ,..._,.Survivin g megaspore (n) Generative cell (n) MITOSIS 3 antipodal cell s (11) Male gametophyte rn \-i........ - 2 polar nuclei (n) 1 egg (n) 2 synergids (n) lliiilaii Ragweed pollen grain Female Gametophyte (n) (embryo sac) Eachof4 microspores (n) Angiosperms – The Flowering Plants ❖ Pollination: Transfer of pollen grains from anther to stigma Pollination by insects, wind, water, animals or gravity. Self-pollination VS. Cross-pollination Can lead to fertilization n E Plant Cycles ❖ Plant Cycle = from seed germination to mature plant producing seeds Annual plants - Cycle completed in single season. Biennial plants - Cycle completed in two growing seasons. Perennial plants - Cycle takes several to many growing seasons or plant produces flowers on new growth, while other plant parts persist indefinitely. Short-lived, long-lived Angiosperms: The Flowering Plants: Apomixis ❖ Apomixis – clonal reproduction without fusion of gametes but with the normal structures otherwise being involved – Embryo from diploid nutritive cell or other diploid cell of ovule, instead of from zygote. o Results in a vegetative propagated plant Bryophyllum daigremontianum Vegetative apomixis in Poa bulbosa; bulbils form instead of flowers Angiosperms – The Flowering Plants Parthenocarpy - Fruits develop from ovaries with unfertilized eggs. – Results in seedless fruits (Navel oranges & bananas) Angiosperms Part 2: Flower Specializations Generalized Flower Morphology (Whorls) pistil 38 Angiosperms – The Flowering Plants ❖ ❖ Trends of specialization and classification in flowering plants: Specialized flowering plants: Flower parts fewer and definite in number. Spiral arrangements compressed to whorls Bilaterally symmetrical flowers = irregular Reduction and fusion of parts – Incomplete or imperfect flowers Inferior ovary Orchid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Other Flower Terminology Term Type ofFlower Complete AlI four parts (sepals, petals, stamens, and carpels) present Incomplete Lacks one or more of the four parts Perfect Has both stamens and (a) carpel(s) Imperfect Has stamens or (a) carpel(s), but not both Inflorescence A cluster of flowers Composite Appears to be a single flower but consists of a group of tiny flowers Complete Flower Incomplete Flower Perfect Flowers: Hibiscus Flowers Pistil with swollen Stigma Stamen (anthers in yellow) Imperfect Flowers Squash Flowers Staminate Flower (male) Pistillate Flower (female) Superior versus Inferior Ovaries Hypanthium - a cup-shaped or tubular body formed by the conjoined sepals, petals, and stamens. Hypogynous (superior ovary) Perigynous (superior ovary) Cherry (Prunus sp.) Epigynous (inferior ovary) Zucchini (Cucurbita pepo) Flower Inflorescences – arrangement of flower heads or clusters Copy,,tgM one McGraw-HIii comp anlea, Inc. 1P m1 alon required for reproaucuon or display. simple umbea Composite Rudbeckia sp. Raceme Catkin Alder False So omon's seal Smtlacina ,acemosa ge aniu Pela gonium sp. Tansy Tanacetum vulgare Corymb Water hemlock Cicu asp. Compo nd umbel Fireweed £pilobium angustifolium compou d umbel · chasium d From MooNt, Clark, and Vodopich, , Botany, 2nd edition.c 1H8 The McGraw HmCompanie. All ri h18 reeerved. Inflorescence: Composite Flower – composed of ray and disc flowers in one flower head Asters (Family Asteraceae) Sexual Manipulators and Drug Dealers – UV Spectrum Nectar (maybe) – Drugs o Pheromones and Fragrance « Violence! Pollination Ecology ❖ Pollinators have coevolved with plants. Twenty thousand bee species among current-day pollinators. Bee-pollinated flowers: – – Generally brightly colored, mostly blue or yellow Often have lines or other distinctive markings, which may function as honey guides to lead bees to nectar. o Bees see UV light (humans do not). « Some flower markings visible only in UV light. In ordinary light In UV light Vegas Baby! ❖ UV Spectrum Vegas Baby! ❖ UV Spectrum Vegas Baby! ❖ UV Spectrum Pollination Ecology ❖ Beetle-pollinated flowers: Strong, yeasty, spicy or fruity odor White or dull in color - Beetles do have keen visual senses. Some do not secrete nectar, but furnish pollen or food on petals in special storage cells. Pollination Ecology ❖ Fly-pollinated flowers: Smell like rotten meat Dull red or brown Odiferous Botanical Trickery! ❖ Pelican Plant (Aristolochia grandiflora) Odiferous Botanical Trickery! ❖ Dead Horse Aurum (Helicodiceros muscivorus) Smells of rotting flesh Lay eggs that never get to become a blowfly Thermal Botanical Trickery! ❖ Arum or Corpse Flower (Amorphophallus titanum) Warm blooded?? Thermal Botanical Trickery! ❖ A Brazilian philodendron (Philodendron bipinnatifidum ) Warm blooded?? Pollination Ecology ❖ Butterfly- and moth-pollinated flowers: Often have sweet fragrances White or yellow for night-flying moths Sometimes red, often blue, yellow or orange for butterflies Nectaries at bases of corolla tubes or spurs for long tongues. Pollination Ecology Bird-pollinated flowers (hummingbirds and sunbirds): ❖ Often bright red or yellow Little if any odor - Birds do not have a keen sense of smell. Large and part of sturdy inflorescence Copious amounts of nectar - Birds highly active. Long floral tubes Pollination Ecology ❖ Bat-pollinated flowers: Primarily in tropics Open at night when bats are foraging Dull in color Large enough for bat to insert head or consist of ball-like inflorescence containing large numbers of small flowers Pollination Ecology ❖ Orchid flowers: Have pollinators among all types mentioned Some of adaptations between orchid flowers and pollinators are extraordinary. Pollen grains produced in little sacs called pollinia (singular: pollinium) with sticky pads at base. Members of Ophrys have modified petal that resembles female bumble bee or wasp. – Male bees or wasps try to copulate with flower. o Pollinia deposited on their head. Drug Dealers ❖ Caffeine Used to give bees a buzz Helps make a faithful “hooked” pollinator Drug Dealers ❖ Nectar (not a drug) Highly nutritious Hummingbirds and Heliconia sp. – Just enough nectar production Botanical Trickery ❖ Bee Orchid (Ophrys apifera) Instigators! ❖ Naughty Orchids Resemble aggressive bee Ouch! ❖ Some plants beat their pollinators into submission Warty Hammer Orchid Fruits ❖ Fruit - Matured ovary and its accessory parts Contains seeds All fruits develop from flower ovaries and accordingly are found exclusively in flowering plants. Tomato fruit Vegetable = any edible portion of a plant Fruit Regions ❖ Exocarp – Skin ❖ Endocarp - Inner boundary around seed(s) ❖ Mesocarp - Tissue between exocarp and endocarp – Peach fruit Three regions collectively called pericarp. Fruits Variability ❖ Can consist of only ovary and seeds ❖ Can include adjacent flower parts ❖ May be fleshy or dry at maturity ❖ May split or not split ❖ May be derived from a one or more ovaries Fruits ❖ Fleshy Fruits - Mesocarp at least partly fleshy at maturity. ❖ Simple fleshy fruits develop from flower with single pistil. Drupe - Simple fleshy fruit with single seed enclosed by hard, stony endocarp (pit) Drupes: peaches, almonds, olives Fruits: Simple fleshy fruits Berry – From compound ovary, with more than one seed, and with fleshy pericarp – True berry - With thin skin and relatively soft pericarp o Tomatoes, grapes, peppers, blueberries, bananas Grape berries – Pepo - Relatively thick rind o Pumpkins, cucumbers Fruits Berry – Hesperidium - Leathery skin containing oils o Citrus Fruits Berry – Pome - Flesh comes from enlarged floral tube or receptacle that grows up around ovary. o Endocarp papery or leathery o Apples, pears - Core and a little of adjacent tissue is from ovary; remainder is from floral tube and receptacle Fruits ❖ Dry Fruits - Mesocarp dry at maturity Dehiscent or indehiscent ❖ Dehiscent fruits - Split at Maturity Follicle - Splits along one side – Larkspur, milkweed, peony Legume - Splits along two sides – Legume family: peas, beans, lentils, peanuts Milkweed follicle Legumes Fruits: Dry Dehiscent ❖ Siliques and silicles - Split along two sides, but seeds on central partition, which is exposed when two halves separate. – Silique - More than three times longer than wide – Silicle - Less than three times longer than wide – Mustard family: broccoli, cabbage Silicle Silique Fruits: Dry Dehisccent ❖ Capsules - Consist of at least two carpels, and split in a variety of ways Irises, poppies, violets, snapdragons A. C. Autograph Tree D. Unicorn plant Fruits: Dry Indehiscent ❖ Indehiscent Fruits - Do Not Split at Maturity Single seed united with pericarp – – Achene - Base of seed attached to pericarp. o Sunflower seed, buttercup, buckwheat Nut - Similar to achene, but larger, with harder and thicker pericarp, and a cluster of bracts at base o Acorns, hazelnuts, hickory nuts Inside of sunflower achene Acorn Fruits: Dry Indehiscent ❖ Grain (Caryopsis) - Pericarp tightly united with seed Grasses: corn, wheat, rice, oats, barley Samaras Corn section Schizocarp of mericarps Schizocarp - Twin fruit Samara - Pericarp that breaks into oneseeded segments called mericarps extends as wings for dispersal. – Maples, ashes, elms – Parsley family: carrots, anise, dill ❖ Aggregate Fruits Derived from single flower with several to many pistils – o ❖ Individual pistils mature as clustered unit on single receptacle. Raspberries, blackberries, strawberries Blackberry aggregate fruits Multiple Fruits Derived from several to many individual flowers in single inflorescence – Mulberries, Osage orange, pineapples, figs Osage orange multiple fruit Fruit and Seed Dispersal ❖ Dispersal by Wind Fruits: Samaras, plumes or hairs on fruit Seeds: Small and lightweight, or with wings Fruit and Seed Dispersal ❖ Dispersal by Animals Seeds pass through digestive tract. Fruits and seeds adhere to fur or feathers. Oils attract ants. – Elaiosomes on bleeding hearts used as food by ants. Fruit and Seed Dispersal ❖ Water Dispersal Some fruits contain trapped air for floatation. Ho d 1i V I d.i i r, 11ni , I Explosive dehiscence of Jewelweed (Impatiens capensis) https://www.youtube.com/watch?v=48YAHg-kY10 Seeds: An important adaptation ❖ Maintain Dormancy ❖ Afford maximum protection ❖ Contain Stored food ❖ Adapted for Dispersal Specialized Adaptations: – Sometimes seeds are in tough cones that do not open until they are exposed to fire – Some germinate only after inhibitory chemicals leach out of the seed coat. Seeds ❖ Structure Ovules develop into seeds. – Cotyledons - Food storage organs that function as “seed leaves” – Embryo = cotyledons and plantlet – Plumule - Embryo shoot – Epicotyl - Stem above cotyledon attachment – Hypocotyl - Stem below cotyledon attachment – Radicle - Tip of embryo that develops into root Bean seed Seed Germination ❖ Epigeous germination Hypocotyl lengthens, bends and becomes hook-shaped. Top of hook emerges from ground, pulling cotyledons above ground. Seed Germination ❖ Hypogeous germination Hypocotyl remains short and cotyledons do not emerge above surface. Germination ❖ beginning or resumption of seed growth. Some require period of dormancy. – Brought about by mechanical or physiological factors, including growth-inhibiting substances present in seed coat or fruit – Break dormancy by mechanical abrasion, thawing and freezing, bacterial action, or soaking rains. o Scarification - Artificially breaking dormancy After ripening - Embryo composed of only of few cells when fruit ripens; seeds will not germinate until embryo develops. Seed Germination ❖ Environmental requirements for germination Availability of oxygen for metabolic needs Adequate temperature for enzyme activity Adequate moisture for hydration of cells Light (in some cases) Scarification: break dormancy due to alterations in seed coat. – Heat, cold, animal intestinal acid, soil microbes ❖ Respiration and metabolism continue throughout dormancy, but at a reduced level 98 Longevity ❖ Seed viability varies, depending on species and storage conditions. Viability extended: – At low temperatures and when kept dry Some seeds can remain dormant for an indeterminent amount of time refereed to as seed bank. Longevity ❖ Vivipary - No period of dormancy; embryo continues to grow while fruit is still on parent. Vivipary in red mangrove Common Plant Families ❖ ❖ Magnoliaceae (Magnolia) Cactaceae (Cactus) ❖ Brassicaceae (Mustard) ❖ Solanaceae (Potato) ❖ Cucurbitaceae (Pumpkin) ❖ Asteraceae (Sunflower) ❖ Poaceae (Grass) ❖ Orchidaceae (orchid) ❖ Agavaceae (agave) Juglandaceae (Walnut) ❖ ❖ ❖ Rosaceae (Rose) Fabaceae (Pea) Family Magnoliaceae (Magnolias) Family Magnoliaceae (Magnolias) Family Juglandaceae (Walnut) Family Cactaceae (Cactus) Cactaceae Diversity Family Cactaceae (Cactus) Family Brassicaceae (Mustard) Family Brassicaceae (Mustard) Family Rosaceae (Rose) Family Rosaceae (Rose) Family Fabaceae (Pea/Legume) Family Fabaceae (Pea/Legume) Family Solanaceae (Potato) Family Cucurbitaceae (Pumpkin) Family Cucurbitaceae (Pumpkin) Family Asteraceae (Sunflower) Family Asteraceae (Sunflower) Family Poaceae (Grass) Family Poaceae (Grass) Family Orchidaceae (orchid) Family Orchidaceae (orchid) Grass Pink (Calopogon tuberosus) Family Orchidaceae (orchid) Family Agavaceae (agave)