Toxic Effects in Plants

In this study, we report the effect of sugars (fructose, glucose, sucrose and trehalose) on Al3+-induced cell death and 02 generation in tomato cell suspension culture using cell death detection dye, Evans blue and 02o -specific chemiluminescent probe, Cypridina luciferin analogue.. Then, the possible roles for trehalose in reduction of Al3+ toxic effects in plants are discussed. 

Paraquat and diquat exert their toxic effects in plants mainly by interacting with photos mthesis, and in animals (and, but probably to a much lesser extent, also in plants) by interacting with mitochondrial respiration. A detailed description of the processes of photosynthesis and mitochondrial respiration would require many pages and is beyond the scope of this book. However, as they are key to the discussion, the following paragraphs have been included to provide a brief overview which is summarised in Figure 2. If the reader is interested in a more detailed account, this can be obtained from any standard biochemistry textbook. 

Iodine has not been shown to be essential to plants, and stimulatory effects on plant growth at low levels have not been reported. Mengel and Kirkby (1978) reported that a stimulatory effect of iodine was observed at 100 pg I L in nutrient solutions, whereas toxic effects in plants occurred at an iodine concentration of 500-1000 pg L b As the toxic concentration is higher than the soluble iodine content of soils, iodine toxicity is rare in plants under natural field conditions. However, a physiological disease of rice plants named Akagare has been reported (Yuita 1979), induced by excessive absorption of iodine from soil enriched with easily soluble iodine when land was converted for submerged paddy fields (Kabata-Pendias and Pendias 1992). 

For mutagenicity of Pb(C2H5)4 in plants, see [406]. Genotoxic effects of Pb(C2H5)4 and other organolead compounds in humans, animals, and plants are reviewed in [442]. For a review of toxic effects in plant organisms, see [440]. 

Poulton, J. E. 1983. Cyanogenic Compounds in Plants and Their Toxic Effects. In Plant and Fungal Toxins-Handbook of Natural Toxins, Vol. 1, Keeler, R. F., and Tu, A. T., eds. New York, Marcel Dekker. pp.117-157. 

Zinc is an essential element and thus can exist in both the deficient or toxic state in plants and animals. Deficiency occurs in some plants when the tissue content drops below 20 ppm. The normal range is 25—150 ppm. The toxic effect of zinc has been seen at 400 ppm, although plants vary widely in their tolerance. 

Physiological Action.—Sulphur dioxide exerts a decidedly toxic effect on plants 3 and animals,4 and has been used in poison ga,s warfare (see p. 106) even as little as 0-04 per cent, by volume in the atmosphere will cause symptoms of poisoning in human beings after a few hours in larger quantities, either gaseous or dissolved, the effect may be fatal. The gas acts as a direct blood poison and also affects the blood circulation.5 The sulphites are not poisonous.6... 

Norton, S. Toxic effects of plants. In Casarett and Doull s Toxicology The Basic Science of Poisons, 6th ed., C. D. Klaassen, ed. New York McGraw-Hill, 2001, pp. 965-976. 

Excessive concentrations of some metals in soils may produce toxic symptoms in plants. Levitt (1980) suggested that metals in the plant environment operate as stress factors in that they cause physiological reaction change (strain) and in so doing can reduce vigour, or in the extreme, totally inhibit plant growth. Sensitivity describes the effects of a stress which result in injury or death of the plant. 

The list of potentially hazardous materials includes drugs, food additives, preservatives, ores, pesticides, dyes, detergents, lubricants, soaps, plastics, extracts from plant and animal sources, plants and animals that are toxic by contact or consumption, and industrial intermediates and waste products from production processes. Some of the information refers to materials of undefined composition. The chemicals included are assumed to exhibit the reported toxic effect in their pure state unless otherwise noted. However, even in the case of a supposedly pure chemical, there is usually some degree of uncertainty as to its exact composition and the impurities that may be present. This possibility must be considered in attempting to interpret the data presented because the toxic effects observed could in some cases be caused by a contaminant. Some radioactive materials are included but the effect reported is the chemically produced effect rather than the radiation effect. 

NO(g), N02(g) n, IV Combustion of fossil fuels, automobiles, denitrification in soils Atmosphere Assists in production of ozone in troposphere, toxic effects on plants... 

The toxic effects in animals are similar to those in humans after ingestion of baneberry. Reports describe seizure activity and paralysis in livestock that ingest large amounts of the fresh plant. Protoanemonin is rapidly polymerized to the inactive anemonin if dried. 

Because of the deficiencies of single-species toxicity tests, alternative approaches are being evolved to address the structural and functional processes of an ecosystem. Multispecies tests include the use of laboratory microcosms, outdoor ponds, experimental streams, and enclosures. There are no standardized procedures for these tests. They are conducted with plant and animal species obtained from laboratory cultures and biota collected from natural sources. They can be conducted indoors or outdoors. The toxic effects, in addition to those used for single-species tests, are determined for structural parameters, such as community similarity, diversity, and density, and for functional parameters, such as community respiration and photosynthesis. Effects on these parameters are reported as the NOEC and LOEC. 

Horses, like other monogastrics, are more resistant to plants capable of causing nitrate-nitrite poisoning than are ruminants. However, horses can modestly reduce nitrates to nitrites in their cecums, but it requires about three times as much nitrate to produce the same toxic effect in horses as in ruminants. 

O Brien, R. D. Effects in plants. In Toxic phosphorus esters. New York ... 

The toxicological impact of polluted soil on humans is indirect. Chemical pollutants in soil affect the ability of soil to support plant life (fertility) by depressing microorganistic and soil-dwelling animal activities. Plants growing in polluted soil absorb toxic chemicals through their root systems and induce toxic effects in humans when those plants are ingested. Polluted soil also adversely affects humans via bioaccumulation of toxic chemicals in animals when plants that have absorbed these chemicals from polluted soil are eaten or when they are dermally absorbed by animals that come in contact with such soil. 

Poulton, J.E. (1983) Cyanogenic compounds in plants and their toxic effects. In Keeler, R.F. and Tu, A.T. (eds.), Handbook of Natural Toxins. Volume 1—Plant and Fungal Toxins. Marcel Dekker, Inc., New York, pp. 117-157. 

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