Angiosperms & Flowering Plants PDF

Angiosperms ((Vessel seed) - structure- ovaries)- produce fruits ) The flowering plants Phylum Anthophyta (Magnoliophyta): Flowering Plants Largest Phylum Heterosporous Sporophytes dominant and independent ○ Female gametophyte wholly enclosed within and dependent on sporophyte. ○ Microspores are rel...

Angiosperms ((Vessel seed) - structure- ovaries)- produce fruits ) The flowering plants Phylum Anthophyta (Magnoliophyta): Flowering Plants Largest Phylum Heterosporous Sporophytes dominant and independent ○ Female gametophyte wholly enclosed within and dependent on sporophyte. ○ Microspores are released to become mature male gametophytes following pollination. Basal Angiosperms ○ Amborella trichopoda ○ Water lilies (2nd oldest) ○ Star anise (3rd oldest) ○ Magnolids ○ Monocots -One seed leaf (orchids, grass, coconut) One Cotyledon Flower parts in multiples of three Leaves with parallel primary veins Vascular cambium and cork cambium absent Vascular bundles of stem scattered Pollen grains one aperture ○ Eudicots -Two seed leaf Two cotyledons Flower parts and multiples of four or five leaves with distinct netted of veins vascular cambium and cork cambium present (not all go through secondary growth) vascular bundles of stem in ring pollen grains with three apertures Seeds enclosed and carpel that resembles a leaf that has folded over infused at the margins Pistil composed of a single carpel or two or more united carpels>>> Seed develops from ovule within a carpel and ovary becomes a fruit.>> Development of Female Gametophyte megasporocyte – megaspore – mature megagametophyte Development of Male Gametophyte Microsporocyte – microspores – mature pollen – mature microgametophyte Mature male gametophyte; germinated pollen grain with its vegetative nucleus and two sperms within tube cell. 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 IMPORTANT!!! General Angiosperm Plant Cycles It is 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 Take several to many growing Seasons or plant produces flowers on new growth, while other plant parts persist indefinitely. short-lived, long lived Apomixis; Clonal reproduction w/out fusion of gametes but normal structures (embryo, ovule) Can become an vegetative propagated plant Parthenocarpy; fruits develop from ovaries with unfertilized eggs Results in seedless fruits ( e.g. navel oranges & bananas) Part 2: Flower Specializations 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 Term Type of Flower Complete Has all 4 whorls (sepals, petals, stamens and carpels) present Incomplete Lacks one or more of the 4 whorls Perfect Has both stamens and (a) carpel(s) Imperfect Has stamens or (a) carpel(s), but not both Inflorescences A clusters of flowers Composite Appears to be a single flower but consists of a group of tiny flowers Complete Flower Carpels; Which produce ovules containing female gametophytes Stamines; which produce pollen grains containing male gametophytes Petals; forming the Corolla Sepals; forming the calyx Incomplete Flower (Ranunculaceae) Perfect Flowers: Hibiscus Pistil with swollen stigma Stamen (anthers in yellow) Imperfect; squash flower Inflorescences; Composite Flower Composed of ray and disc flowers in one flower head (Asters~ Family Asteraceae) e.g sunflower Hypanthium- a cup-shaped or tubular body formed by the conjoined sepals and petals and stamens. Hypogynous; It is considered, if a flower’s ovary is superior and the hypanthium is absent. Perigynous; It is considered, if a flower’s ovary is central and the cup-like hypanthium is present. Epigynous; It is considered, if a flower’s ovary is inferior and a fused hypanthium is absent. Fruits Fruits; matured ovary and it accessory parts -contains seeds -All fruits develop from flower ovaries and accordingly are found exclusively in flowering plants Vegetable= any edible portion of a plant Fruit Regions Exocarp- Skin Endocarp- Inner boundary around seed(s) Mesocarp- Tissue between exocarp and endocarp Three regions collectively called pericarp Fruit 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 one or more ovaries Fleshy Fruits- Mesocarp At least partly fleshy at maturity. Simple fleshy fruits developed from flower within a single pistil Drupe; simple fleshy fruits with single seed enclosed by hard, stony endocarp (pit) (peaches, almonds and olives) 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 ○ e.g ; Tomatoes, grapes, Peppers, and bananas, blueberries Pepo; relatively think rind ○ E.g’ pumpkins and cucumbers Hesperidium- berry with a leathery rind (containing the leathery oil) ○ E.g; lemon (citrus lemon) Pome- flesh comes from enlarged floral tube or receptacle that grows up around ovary ○ Endocarp papery or leathery ○ Apples, pears- core and a little adjacent tissue is from ovary; remainder is from floral tube and receptacle. >>> Dry fruits- Mesocarp dry at maturity ○ Dehiscent or indehiscent Dehiscent fruits (DRY DEHISCENT)- Split at Maturity ○ Follicle- Splits along one side Larkspur, milkweed, peony ○ Legume- Splits along two sides Legume family: peas, beans, lentils, peanuts Siliques and Silices; Split along two sizes, but seeds on Central and partition, which is exposed when two halves separate. ○ Silique; more than 3x longer than wide ○ Silicle; less than three 3x longer than wide ○ Mustard family: broccoli, cabbage Capsules; Consist of at least two carpels, and split in variety of ways ○ Iries, poopied, violets and snapdragons Indehiscent fruits (DRY INDEHISCENT); Do Not split at Maturity) Single seed united with pericarp ○ Achene; base of seed attached to pericarp. Sunflower seed, buttercup, buckwheat ○ Nut; Similar to achene, but larger, with harder and thicker, pericarp, and a cluster of bracts at base Acorns, hazelnuts, hickory nuts Grain ( Caryopsis) - pericarp tightly united with seed ○ Grasses: corn, wheat, rice, oats and barley ○ Samara- pericarp extends as wings for dispersal Maples, ashes and elms ○ Schizocarp-Twin fruit that breaks into one-seeded segments called mericarps Parsley Family: carrots, anise, and dill Aggregate fruits; Derived from single flower with several to many pistils ○ Individual pistils mature as clustered units on a single receptacle. Raspberries, blackberries and strawberries Multiple fruits; Derived from several to many individual flowers in single inflorescence ○ Mulberries, Osage, orange, pineapples, figs Fruit and Seed Dispersal Dispersal by Wind Fruits: Samara, plumes or hairs on fruit Seeds: Small and lightweight, or with wings 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 Water Dispersal Some fruits contain trapped air for floatation Seeds: An Important Adaptation Maintain Dormancy Afford maximum protection Contain stored food Adapted for Dispersal Specialized Adaptations ○ Sometimes seeds are 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; cotyledon and plantlet ○ Plumule; Embryo shoot Epicotyl; stem above cotyledon attachment Hypocotyl; stem below cotyledon attachment Radicle; Tip of embryo that develop into root Seed Germination Epigeous germination ○ Hypocotyl lengthens, bends and becomes hook-shaped ○ Top of hook emerges from ground, pulling cotyledons above ground Hypogeous germination ○ Hypocotyl remains short and the cotyledons do not emerge above surface Beginning or resumption of seed growth ○ Some require period of dormancy Brought about by mechanical or physiological factors, including growth inhibiting substances present and Seed coat or fruit. Break dormancy by mechanical abrasion, thawing and freezing, bacteria action, or soaking rains. scarification -Artificially breaking dormancy After ripening -Embryo composed of only a few cells when fruit ripens; seeds will not germinate until embryo develops. Environmental requirements for germination ○ availability of oxygen for metabolic needs ○ adequate temperature for enzymes activity ○ adequate moisture for hydration of cells ○ Light (in some cases) ○ scarification: break dormancy due to alterations and Seed coat heat cold animal intestinal acid soil microbes Respiration and Metabolism continue throughout dormancy, but at a reduced level. Longevity Seed viability varies, depending on the species and Storage conditions. Viability extended: ○ At low temperatures and when kept dry Some seeds can remain dormant for an indeterminent amount of time referred to as seed bank. Vivipary; NO period of dormancy; embryo continues to grow while fruit is still on parent. ○ Vivipary in red mangrove