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ESTELLE LEVETIN & KAREN MCMAHON Chapter 21 http://www.botany.org/Carnivorous_Pla nts/
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Everywhere in environment, wild, yard, houseplants Evolved chemicals protect them from insects, pests, herbivory Capable of triggering allergic reactions Alkaloids and glycosides poisonous compounds Fatal at certain doses
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Nitrogen containing secondary metabolites Usually alkaline Bitter in taste Effect on central nervous system Caffeine and cocaine stimulants Morphine and codeine depressants Fabaceae, Solanaceae, Rubiaceae
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Signal transduction, and the function of gene promoters regulate alkaloid metabolism Enzymes involved in alkaloid cytosol, vacuole, tonoplast membrane, endoplasmic reticulum, chloroplast stroma, thylakoid membranes, and perhaps unique "biosynthetic" or transport vesicles Isolated genes have used to genetically alter the accumulation of specific alkaloids
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ALKALOIDS AND SOURCES Caffeine Ephedrine Quinine (Cinchona spp.) Morphine (Papaver somniferum) Cocaine (Erythroxylum coca) Atropine (Atropa belladona)
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Solanaceae Tropane alkaloids relax smooth muscles Dilate blood vessels, increase heart rate and body temperature Induce sleep and lessen pain Induce Hallucination
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Atropa belladona herbaceous perennial Belladona was applied to eyes by many women Dilation of pupil producing an alluring effect Belladona “beautiful lady” Henbane (Hyoscymus spp.) Mendrak (Mandrogora officinarum) Three plants used by witches to prepare magic potions
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These decoctions induce hallucination and frenzies during witch convocations Images of witch flying through air on broomsticks and transforming themselves as animals originated as delusions of their drug-induced state Datura “poison”
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Strychnine from Strychnos spp. induces muscle convulsions Used illegally to enhance athletic performance Rodent poison Curare arrow poison employed by many South American tribes
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Curare from Strychnos spp. and Chondrodendron spp. Injection of curare results in immediate muscle relaxation by blocking nerve impulses Poison hemlock and water hemlock poisonous plants in North America
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Strychnos toxifera
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Poison hemlock Conium maculatum
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Water hemlock grows in water or swampy areas Cicutoxin in high concentration in yellow sap exuding from roots Produces convulsions Milkweeds (Asclepias spp.) produces resinous toxin and cardioactive glycosides Monarch butterfly larvae eat milkweed without any injuries and feed on milkweeds
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Water hemlock Cucuta maculata
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Asclepias curassavica
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Nerium oleandar (Apocynaceae) more than 50 toxin compounds cardioactive glycosides, oleandroside, nerioside similar in action to digitalis Yews, Taxus spp. Poisonous herbs Taxine alkaloids in all parts of plant body
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Nerium oleandar
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Taxus baccata
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Rhododendrons and azales (Ericaceae) poisonous compounds Grayanotoxins Pollen, nectar, honey poisonous Poisoning of honey Bees poisoned by rhododendrons
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Fabaceae source of alkaloids Rosary pea (Abrus precatorius) Black locust (Robinia pseudoacacia) Tulips, star-of-Bethlehem, daffodils poisonous
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Abrus precatorius
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Star-of-Bethlehem
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Rhododendron spp.
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Spurge (Euphorbiaceae) harmful due to milky sap (latex) Most spp. of Euphorbia cause skin irritation Ricinus communis toxic Black walnut tree and Parthenium show allelopathy Pollens of some plants cause allergy
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Parthenium integrifolium
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400 spp. of angiosperms carnivorous Carnivorous traits due to poor nutrient conditions Modified leaves for traps, mostly colored to attract insects Once insects trapped, digestive enzymes released Venus ‘-Flytrap, Sundew, pitcher plants
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Venus ‘-Flytrap (Dionaea spp. )native to North Carolina Sundews (Drosera spp.) use flypaper-like leaves to trap insects Glandular hairs on leaves produce adhesive ‘super-glue of plant kingdom’ Pitcher plants (Sarracenia spp.) leaves evolved into vase or pitcher Insects lured to pitcher and slips into pool of rainwater collected at base Pool contains digestive enzymes
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Sarracenia spp.
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Dionaea spp.
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Drosera spp.
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