BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

IV. PLANT ANATOMY AND MORPHOLOGY

Toxic Substances

Plant toxins are classified into 12 groups.

Alkaloids are found in plants predominantly as salts of organic acids; they are highly Water-soluble, which accounts for their toxicity. However, not all alkaloids (and over 1,000 are known) are toxic. The majority of alkaloids affect The Nervous system. Some of them suppress the Central Nervous System (opium, morphine, pantopon, scopolamine), while others, conversely, stimulate it (caffeine, strychnine). Certain alkaloids target different PARTS OF THE nervous system as well as specific Organs. Death from alkaloid poisoning results from paralysis.

Alkaloid-bearing plants include the following: monkshoots (aconites), autumn crocuses, barnyard grasses, poppies, hellebores, tobacco, greater celandine, poison hemlock, black henbane, Syrian rue, hemlock stork's bill, thornapple, heliotropes, and many other species.

Glycosides are the most widespread plant toxins. Among glycosides, toxic properties are exhibited by:

a) nitrile or cyanogenic glycosides, the Enzymatic Cleavage of which produces highly toxic hydrocyanic acid (bogbean, marsh bird's-FOOT trefoil, flax, sea arrowgrass, mannagrass, alfalfa, clover, millet, sorghum, etc.);

b) thioglycosides, or mustard glycosides, which are enzymatically cleaved to form essential mustard oil (mustard, rapeseed, marsh yellowcress, radish, field mustard, field pennycress, and other plants, predominantly from the Brassicaceae/Cruciferae family);

c) cardenolides and bufadienolides (cardiac glycosides), which affect The Cardiovascular system (pheasant's eye, foxgloves, lily of the valley, oleander, hemp dogbane, wallflower, hellebore);

d) triterpene glycosides (saponins);

e) steroid glycosides (saponins).

Triterpene glycosides predominate among saponins. They exhibit very strong hemolytic activity. The highest hemolytic index is found in marsh marigold, baneberry, bristly goosefoot, clematis, ninebark, scarlet pimpernel, Jacob's ladder, and baby's breath. In addition to hemolytic activity, saponins possess diuretic properties (baby's breath) and also influence the Excitation and Inhibition processes of the central nervous system.

Glycoalkaloids are glycosides whose aglycones are formed by alkaloids, primarily solanidine. They are characteristic of The Nightshade family (Solanaceae). In potatoes, for example, two glycoalkaloids have been found: solanine and the more toxic chaconine. Large amounts of solanine and chaconine are present in potato sprouts, buds, flowers, and young leaves. In tubers, they are concentrated mainly in the Skin. The amount of glycoalkaloids in tubers increases during sprouting and when greening under METABOLISM/18.html">The Influence of light. Wild potato (Solanum demissum) contains the glycoalkaloid demissine, which renders it unpalatable to Colorado potato beetle larvae. Solanine has also been found in black nightshade and bittersweet nightshade.

Toxic albumins are protein-containing toxic substances. These include ricin from castor bean seeds, robin from black locust bark, and phasin from common bean seeds.

Lactones are esters of cyclic organic gamma and delta acids. They include coumarin from sweet clover and holy grass, protoanemonin from buttercup, and tauricin from wormwood.

Essential Oils are volatile substances. An example is allyl mustard oil. It is present in members of the Brassicaceae family (wild mustard, white mustard, rapeseed, shepherd's purse, horseradish, field pennycress, flixweed, peppergrass) and Alliaceae (onion, garlic).

Organic acids and their salts. Poisoning can be caused by the following acids: oxalic (sorrel, wood sorrel, beet greens), euphorbic (spurge), filicic (male fern), and aconitic (horsetails).

Nitrates and nitrites are salts of nitric and nitrous acids. Corn and beets are traditionally rich in them. The accumulation of substances in this group in cultivated and wild plants occurs in cases of nitrogen fertilizer excess in the soil, as well as under the influence of unfavorable environmental conditions (drought, prolonged heavy rains, extreme Temperature fluctuations, frosts, trampling, hail). Carriers of nitrates include such forage and food crops as watermelon, melon, field pea, zucchini, cucumbers, potatoes, corn, cultivated oats, wheat, rye, barley, sorghum, millet, ryegrass, beets, clover, alfalfa, rapeseed, cabbage, and turnip. Among wild plants, common ragweed, sweet clover, thistle, thornapple, lesser stitchwort, stinging nettle, lettuce, goosefoot, orache, spurge, nightshade, purslane, milk thistle, garden sorrel, pigweed, and puncturevine are rich in nitrates.

Mineral salts. Poisoning by mineral compounds is well-known, including sodium and potassium chlorides and carbonates, and magnesium, potassium, and sodium sulfates. Sheep, and particularly lambs, are sensitive to this group of toxic substances. Saltbush, orache, khaki weed, glasswort, and seepweed are rich in mineral salts.

Pigments (photosensitizers). After ingestion of plants containing such pigments, inflammatory processes occur in unpigmented areas of the skin and subcutaneous tissue. The cause is an increased sensitivity of the Organism to ultraviolet rays of the solar spectrum—photosensitization. Such pigments are found in buckwheat (fagopyrism), clover, millet, St. John's wort, tall flixweed, common cocklebur, and buttercups.

Resinous substances cause sharp local action and inflammation of the skin (dermatitis) as well as the mucous membrane of the digestive tract (enteritis). They have been identified in the bark of mezereon, bindweeds, and water hemlock.

Plant toxins of unknown nature are contained in hawkweed, mountain ironwort, lesser stitchwort, goosefoot, Tartar lettuce, water hemlock, boneset, hops, and grass pea.

Plant Cell substances are conventionally divided into two large groups: constitutional and ergastic. The former are functionally active substances. Among them, structural, physiologically active, and metabolic substances can be distinguished. Structural substances include Cellulose, hemicellulose, and pectin of cell walls, as well as Membrane Proteins and Lipids. Physiologically active substances in The Cell are represented by Vitamins, Enzymes, phytohormones, Antibiotics, and phytoncides. Metabolically active substances are starting or intermediate compounds utilized in the cell's metabolic cycles.

Ergastic substances are non-living inclusions excluded from active metabolism. They are subdivided into reserve substances, which are temporarily removed from metabolism, and metabolic end products. Reserve substances include CARBOHYDRATES (Monosaccharides and Polysaccharides—starch, inulin, Glycogen), fats in the form of oil droplets, and aleurone grains or protein globules. Metabolic end products include alkaloids, glycosides, essential oils, resins, etc.