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.