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ESTELLE LEVETIN & KAREN MCMAHON
Chapter 21
http://www.botany.org/Carnivorous_Plants/
PLANT AND SOCIETY
Everywhere in environment, wild, yard, houseplants
Evolved chemicals protect them from insects, pests, herbivory
Capable of triggering allergic reactionsAlkaloids and glycosides poisonous
compoundsFatal at certain doses
POISONOUS PLANTS
Nitrogen containing secondary metabolitesUsually alkalineBitter in tasteEffect on central nervous systemCaffeine and cocaine stimulantsMorphine and codeine depressantsFabaceae, Solanaceae, Rubiaceae
ALKALOIDS
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
ALKALOIDS AND SOURCES
CaffeineEphedrineQuinine (Cinchona spp.)Morphine (Papaver somniferum)Cocaine (Erythroxylum coca) Atropine (Atropa belladona)
SolanaceaeTropane alkaloids relax smooth musclesDilate blood vessels, increase heart rate and
body temperatureInduce sleep and lessen painInduce Hallucination
Tropane Alkaloids and Witchcraft
Atropa belladona herbaceous perennialBelladona was applied to eyes by many
womenDilation of pupil producing an alluring effectBelladona “beautiful lady”Henbane (Hyoscymus spp.) Mendrak (Mandrogora officinarum)Three plants used by witches to prepare
magic potions
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”
Strychnine from Strychnos spp. induces muscle convulsions
Used illegally to enhance athletic performance
Rodent poisonCurare arrow poison employed by many
South American tribes
Poisonous Plants in the Wild
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
Strychnos toxifera
Poison hemlock Conium maculatum
Water hemlock grows in water or swampy areas
Cicutoxin in high concentration in yellow sap exuding from roots
Produces convulsionsMilkweeds (Asclepias spp.) produces
resinous toxin and cardioactive glycosides
Monarch butterfly larvae eat milkweed without any injuries and feed on milkweeds
Water hemlock Cucuta maculata
Asclepias curassavica
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
POISONOUS PLANTS IN BACKYARD
Nerium oleandar
Taxus baccata
Rhododendrons and azales (Ericaceae) poisonous compounds
Grayanotoxins
Pollen, nectar, honey poisonous
Poisoning of honey
Bees poisoned by rhododendrons
Fabaceae source of alkaloids
Rosary pea (Abrus precatorius)
Black locust (Robinia pseudoacacia)
Tulips, star-of-Bethlehem, daffodils poisonous
Abrus precatorius
Star-of-Bethlehem
Rhododendron spp.
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
Parthenium integrifolium
400 spp. of angiosperms carnivorousCarnivorous traits due to poor nutrient
conditionsModified leaves for traps, mostly colored
to attract insectsOnce insects trapped, digestive enzymes
releasedVenus ‘-Flytrap, Sundew, pitcher plants
Carnivorous plants
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
Sarracenia spp.
Sarracenia spp.
Dionaea spp.
Drosera spp.