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PLANT AND SOCIETY

PLANT AND SOCIETY. ESTELLE LEVETIN & KAREN MCMAHON Chapter 21 http://www.botany.org/Carnivorous_Plants/. POISONOUS PLANTS. Everywhere in environment, wild, yard, houseplants Evolved chemicals protect them from insects, pests, herbivory Capable of triggering allergic reactions

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PLANT AND SOCIETY

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  1. PLANT AND SOCIETY ESTELLE LEVETIN & KAREN MCMAHON Chapter 21 http://www.botany.org/Carnivorous_Plants/

  2. POISONOUS PLANTS • 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

  3. ALKALOIDS • 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

  4. 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

  5. ALKALOIDS AND SOURCES • Caffeine • Ephedrine • Quinine (Cinchona spp.) • Morphine (Papaver somniferum) • Cocaine (Erythroxylum coca) • Atropine (Atropa belladona)

  6. Tropane Alkaloids and Witchcraft • Solanaceae • Tropane alkaloids relax smooth muscles • Dilate blood vessels, increase heart rate and body temperature • Induce sleep and lessen pain • Induce Hallucination

  7. 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

  8. 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”

  9. Poisonous Plants in the Wild • Strychnine from Strychnos spp. induces muscle convulsions • Used illegally to enhance athletic performance • Rodent poison • Curare arrow poison employed by many South American tribes

  10. 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

  11. Strychnos toxifera

  12. Poison hemlock Conium maculatum

  13. 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

  14. Water hemlock Cucuta maculata

  15. Asclepias curassavica

  16. POISONOUS PLANTS IN BACKYARD • 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

  17. Nerium oleandar

  18. Taxus baccata

  19. Rhododendrons and azales (Ericaceae) poisonous compounds • Grayanotoxins • Pollen, nectar, honey poisonous • Poisoning of honey • Bees poisoned by rhododendrons

  20. Fabaceae source of alkaloids • Rosary pea (Abrus precatorius) • Black locust (Robinia pseudoacacia) • Tulips, star-of-Bethlehem, daffodils poisonous

  21. Abrus precatorius

  22. Star-of-Bethlehem

  23. Rhododendron spp.

  24. 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

  25. Parthenium integrifolium

  26. Carnivorous plants • 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

  27. 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

  28. Sarracenia spp.

  29. Sarracenia spp.

  30. Dionaea spp.

  31. Drosera spp.

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