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Author abstract I E. F» Barley, 8. Hugger, J. Hudd, L. Ordin, Taylor, and I. Health 6, 7. Emissions from motor vehicles are now known to be the principal source of the raw materials contributing to photochemical air pollution in California. Ethylene, one of the compounds found in the exhaust, is also very injurious to several crops.. The ability of a given toxicant to incite injury is dependent on the age of the leaf and the conditions of illumination under which the plant is grown prior to, during, and after fumigation..
In addition, the growth of plants, even in the absence of visible injury, is laterially affected. Evidence is presented to indicate that the chemical and physical systems within the plant are disrupted by the phytotoxicants. Kendrick, Jr. The response of pinto beans to air-borne oxidants occurring in the Los Angeles area are described.
The survey data were subjected to further analysi by comparing the prercent of plants damaged at five stations with the oxidant mean and maximum ranges observed. Data is presented and show that the mean percent of plants damaged increased with increasing oxidant maximum.
Author states that the experiment described is the first of its kind designed to determine the relationship between plant damage and oxidant level in the naturally polluted Los Angeles Basin. The results of the study show that the frequency of damage to plants is associated with the oxidant concentrations for both oxidant maximum and daily oxidant mean.
Hiddleton, J. Kendrick, Jr.. These laboratory investigations revealed that concentrations of oxidized hydrocarbons as low as 0. These observations corroborated those lade in the field showing that damage to crop is directly proportioned to the length of the pollution period, ftethods fcr protection of plants are being studied and briefly discussed in this paper. Calif-, Agr The components identified causing this damage were certain clefinic peroxides, found when iie reacts with the vapors of unsaturated hydrocarbons derived from gasoline and other petroleum products.
Research is in fzogtess to develop methods for the economic production of agricultural crops in areas affected by air pollution. It is concluded that abatement measures must be taken to protect agricultural areas. Darley, R. Presented at the 22nd Midyear fleeting, American Petroleum Inst. Division of Refining, Philadelphia. Pa« lay 14, Vegetation damage has increased with industrialization and urban development.
Whereas the principal plant toxicants recognized several decades ago were sulfur dioxide and fluorine, in the last decade a nev group of airborne phytotoxicants has been described and identified as oxidants. The principal source of these oxidants is believed to be photolysis reaction products of auto exhaust. Atmospheric contaminants responsible for damage to vegetation may be described as particulates - such as dusts and acid aerosols - and gases - such as sulfur dioxide, halogens, oxidized organics, ozone, nitrogen dioxide, hydrogen sulfide, ammonia, and carbon monoxide.
Of these diverse pollutants, gases generally cause more damage to plants than do particulates. Hiddleton A. Health 14, , Dec.. This paper presents an annual summary of monthly tabulations shoving plant damage occurring in 12 ot 51 counties. Regional tabulations show that plant damage is limited to the San Francisco Bay area and the coastal plain of southern California.
The areas reporting plant damage are those of greatest population density. The toxicants responsible for plant damage are recognized in decreasing order of importance as oxidized hydrocarbons, ethylene and fluorides, sulfur dioxide is of unusual occurrence and its distribution usually associated with specific industrial wastes. It is generally believed that ozcne is present in the urban areas of Los Angeles and San Prancisco and responsible for a significant part of the total atmospheric pollution.
The wide-spread distribution of ethylene and smog, or reaction products from the oxidation of hydtocarons, emphasizes the need fox regional, research and abatement programs. The toxic components in photochemical air pollution are typically G. This paper describes the occurrence and distribution of photochemical air pollution, enumerate seme of the raw materials and products of these oxidation systems responsible for plant damage, and indicate the biochemical, physiological, and pathological effects of these contaminants upon plants.
Brewer, O. Xn many of the important growing areas of California the production and quality of vegetables and crops are adversely affected by air-borne toxicants such as ethylene, fluorides, herbicides, oxidized hydrocarbons, ozone and sulfur dioxide.
Leaves of celery, lettuce, spinach, and some other vegetables, and of flower crops and African violets usually show silvering and glazing on their lower surfaces, sonetines followed by a bronze or reddish discoloration.. Examples of the plant damage are shown in color photographs. This does not include economic losses fro reduced growth and lowered production in the absence of visible injury.
This article compares the relative susceptibility of some plants to oxidants to determine the plant-damaging effects of hydrocarbon, ozone, and ozonated olefins, and to describe the response of the pinto bean to air borne oxidants occurring in the Los Angeles area- Plants vary in their susceptibility to the reaction products from the oxidation of hydrocarbons. The pinto bean has been selected as a test plant for measuring the mechanisms of damage and seme of the effects of oxidized hydrocarbons upon the life processes..
Controlled fumigations have shown that the severity of plant damage varies with the ait temperature. The atmosphere in los Aageles and San Francisco has allegedly high concentrations of ozone. Tet typical crop damage there is reproduced only by ozonated olefins and not by ozone alone. The specific symptoms incited by exposure to oxidants'cau be used to determine the presence at ozonated olefins and ozone in polluted air masses.
Stephens, E«. Taylor, W. Presented at the 25th Hidyear fleeting, American Fetroleum Inst. Division of Refiaing, Detroit, flick. One end forms a carbonyl compound, and the other yields a variety of products. Among these is a highly oxidized, unstable organic nitrogen confound previously described as compound X or peroxyacetyl nitrite PAH and detected in polluted atmospheres. This compound has now been purified by gas chromatographic techniques, and its chemical, physical, anfl physiological properties have been examined.
At concentrations well below 1 p. Pin is the first pure compound isolated from photochemical reaction mixtures which has been found to produce the characteristic oxidant damage symptoms. Author abstract! Todd 15P1CT O? The enzymes catalase, peroxidase, Fapain and urease were treated in vitro with low concentrations of ozone gas. Ride variations were found in the sensitivity of the G. Effects -Plants and Livestock enzyaes to the inhibitor; action of the gas.
Papain showed the greatest sensitivity; the test required a much greater amount of ozone for inactivation. The treatment of Pinto bean leaves with either ozone or ozonated hexene gas in air caused a rise in the respiration rate up to more than four tiaes that of untreated control leaves. Plant responses to the two gases were siailac. The rate of photosynthesis of treated bean leaves was less than that of controls.
Both the amounts of stiaulation of respiration and the inhibition of photosynthesis were directly related to the developaent of visible injury symptoms in certain tissues of the bean leaves. Mo stimulation of bean leaf respiration or inhibition of photosynthesis occurred unless visible injury developed.
Treatment with ozonated hexene at concentrations eliciting changes in respiration and photosynthesis in bean leaves caused no change in these processes in citrus leaves. Todd, J. Hiddleton, and B. Agr« , It, July SyaptoMs of plant daaage in the field can often be identified as the effect of one or more air pollutants.
However the exact aechaniaas whereby the plant is daaaged and the various manifestations of daaage - after fumigation with air toxicants - are not well understood, soae forage and vegetable crops, alfalfa , coaaon bean, garden and sugar beet, lettuce, spinach, and tcaato, grow and yield poorly in polluted atmospheres such as Los Angeles and San Francisco. Reduced growth and production can occur without leaf necrosis. Effects on plant life processes were investigated.
Changes in membrane perneability were studied by exposing table beet, bean leaf and potato tuber tissue to ozonated hexene. In the case of the beet tissue, the changes brought about caused the anthocyanin pigment of the beet to diffuse out when the tissue was placed ia viater. Ozonated hexene first caused a decrease then followed by an increase in perneability in the potato and bean tissues. Exposure to ozone and ozonated gasoline caused reduction in growth of Kentia pains and Todd Hexican avocado seedlings.
The uechanisos whereby plants are damaged and the various ways in which they nay show vaultestations after fumigation by air pollutants are reviewed. The discussion is priaarily concerned with the effects of ozone, ozonated unsaturated hydrocarbons, naturally-occurring air pollutants in the Los Angeles basin, and to a saall extent hydrogen fluoride.
Todd and tl. Fuaigations with ozonated hexene caused a repression in growth of bean plants varieties Bed Kidney and Bountiful even though they showed no visible syaptoas of injuty. Both priaary and trifoliolate leaves failed to enlarge as inch as control leaves when treated with ozonated hexene, although the treataent seeaed to have little or no effect on the nuaber of leaves inititated.
Primary leaves on treated plants aged and ware lost preaaturely. Steas of plants treated with ozonated hexene consistently had a higher water content than did steas of control plants. The leaves did not show this relationship. Ozone alone caused no repression of growth, and repeated faaigations of pea plants with 1-hexane elicited no response. This is due to a series of cross vails which cut in parallel to the broad surface of the leaf in normally static, spongy nesophyll cells. Anthocyanin increases in the damaged areas and lower epidermal cells nay collapse.
The walls of the initially damaged cells, those of the collapsed epidermal cells, and intercellular spaces between become heavily suberized, sealing the lower surface of the leaf. This layer is properly designated the pseudocicatrice- All and functional; the only abnormality is in the region of accelerated suberization.
The cells of the lover spongy oesophyll in the immediate vicinity of damage begin to divide by tangential vails to torn a cicatrice parallel to the flat surface of the blade- These nev wails are at first pure cellulose, as they grow older, they becone more and more heavily suberized. By compression against one another as the mother cell continues to form new walls above, a heavily suberized protective cork layer, the cicatrice, is formed. This stimulation to unusual vail formation in cells, which under normal conditions would not enlarge or divide, is definitely in response to tissue trauma.
Renewed cellular activity cannot be biased directly on the toxicity of a snog component. Indirectly, however, by causing the death of some cells, it may induce chemical changes within the leaf, which, in turn, induce the formation of cork. Author summary R. Glater, fU A. Solberg, and F- 0. Plants growing in the fields of Los Angeles County as well as those experimentally fumigated in the laboratory shov gross markings in response to smog which vary from species to species, from a glistening appearance of the leaf undersurface due to a temporary accumulation of water in the affected cells through complete necrosis.
The normal anatomical development of the foliage was studied and correlated with its susceptibility tc smog injury. On a given plant, leaves of different ages show damage in different positions. Very young leaves at the apex of the plant and old leaves at the base of the plant are not sensitive.
Expanding leaves between young and old in age are sensitive; in this group a distinct pattern of damage is discernible. Damage Barkings in the youngest leaves appear only at the tip; in leaves somewhat older, close to midblade; in fully mature leaves, only at the base. This localization of damage is shown tc be correlated with the gradient of cellular differentiation frcm tip toward base as the leaf matures.
Botany 42, t«. Bay In the field, the characteristic response to hydro-carbon-oxidation products is seen to be a tan spotting or transverse banding limited to the region between tip and midblade of susceptible leaves. This damage has been duplicated in the laboraroty with synthetically-produced smog. Tissue damage Is similar to that previously described in spinach, beets, oats and other plants.
The cells which are initially and most seriously damaged are those surrounding the substomatal chambers. Chloroplasts disintegrate, plasuolysis follows, and ultimate total dehydration of damaged cells results in part or all of the mesophyll tissue in affected areas becoming "mummified. Localisation of damage is related to the gradient of cellular differentiation from tip to base in the linear leaf; the sensitive region is limited to those cells which have just completed maximum expansion.
Bobrov G. Poa annua is considered a very reliable biological indicator for atmospheric smog for several reasons: i the extreme sensitivity of its cells to minute quantities of phytotoxic Materials; ii its method of cellular differentiation from tip toward base in the linear leaf with resulting narked transverse leaf banding; and iii its ubiquity as a need in Los Angeles County, Baking a naturally occurring check available in aany and scattered areas.
Work is in progress in an attmept to calibrate this plant as a quantitative, as well as a qualitative, bioassay material. A detailed account of the anatcmy of normal and snog damaged Poa has been completed.. Phytopathology U2t 10 , Oct. Smog in the los Angeles area causes serious damage to the oat crop.
Daaage depends upon the normal anatomical pattern of the parallel-veined leaf, upon the stromata as a portal of entry for the harmful elements in the air, and upon the amount of internal air space in the leaf. Initial daaage nay be observed microscopically, as the cells directly lining the substomatal chambers shrink.
As acre and sore cells are affected, longitudinal streaking of the leaves occurs, corresponding to the position of the stoaatal zones. Ultimate browning and death of the entire blade nay results. The extent of injury is in proportion to the concentration of snog in the air.
Sensitivity also is influenced by CO concentration time of day, and age of plant at tine of exposure. Tobacco shows cumulative development of injury when exposed to low concentration intermittently over several days. The following aspects of ozone injury to plants are reviewed: Natural sources of ambient ozone; what plant species are susceptible; the symptoms produced; environmental predisposition; Metabolic effects; and how plants nay be protected.
A review of information derived from both field and laboratory investigations of the effects of air pollutants on terrestrial animals indicates that 1 of all known air pollutants, economic poisons pose the greatest current threat to the health of wildlife. Synergism, the exalted or potentiated toxic effect of combination of certain air pollutants: its converse, antagonism, in which the sommated toxicity is either far less than predicted or nonexistent, b.
Tolerance and cross tolerance to pulmonary edema-producing agents, c. The immunochemical response. Koukol, R. Seed, B. Addition cf ascorbate to the chloroplast- ccntaininq reaction aixtures virtually eliminated this inhibition. Exposing the cblcrcplasts or other components of the reaction, either separately or as a aixture, to peroxyacetyl nitrate in the dark followed hy a light period without the oxidant did not effect the C fixation process,, This inhibition in the intact plant, as well as in the chloroplast, appears to be one of quantitative reduction ia the early products of the photosynthesis and not a qualitative change.
E« Reggestad 1. Evidence obtained by neans of rubber strip tests and on ozone recorder indicates the presence of abnormal concentrations of ozone in the atmosphere at tines. The great similarity between lesions occurring naturally and those produced by ozone In chambers also indicates that ozone is the probable inciting agent of weather fleck- Varietal differences exist, study of stoaatal action helped to explain variation in leaf injury.
Ledbetter, P.. IAGE, Contcib. Boyce Thompson Inst. Bint, and geraniaa. Tinder the conditions of this test, gladiolus, kalanchoe, pepper, bean Tendergreen , and piggy-back plant were not visibly injured by concentrations up to 1v0 p. Foliage injury appeared in vatying aiounts as dark stipples, light flecks, necrotic patches, and general chlorosis. The light- colored flecks were associated with a collapse of the palisade cells without pigment formation.
In general, very young leaves that had no functional stomata were resistant to ozone- The leaves become susceptible only as the stomata become functional. In variegated coleus injury was largely associated with the pigmented sectors presumably due to the greater functioning and freguency of the stomata, or to the greater sensitivity of these tissues to ozone.
Plant Physiol.. The characteristic components of this aggregate were reaains of the chlocoplast aeabrane systea and nuierous ordered arrays of granules and fibrils. These changes were identical with those previously observed in cells damaged by peroxyacetyl nitrate and were probably related to the oxidation properties of both molecules.
Author abstract C. Theapson, and O. ASAE A a. After three years of operation, the durability and convenience of the structores described are very satisfactory. No discoloration, crazing or cracking of the plastic glazing listeria 1 is apparent, paint on the aluainua is holding well. Repainting on some steel surfaces was necessary after two years.
Activated carbon and liaestone for removing photochemical snog and fluorides, respectively, froa the air streams aest be renewed about every 12 hoars. Soae minor damage was done by windstorms of 80 mph, which was easily taken care of. C B. Pink Ribbed; oats, var.
Kanota; spinach, var- Viroflay; asd toaato, var. San Jose Canner. A sensitive biological assay for detection. Differential sensitivity of cotyledons and young foliage leaves to saog injury was observed. The growth of alfalfa, and especially of endive, has been greatly increased by carbon filtration of the atmosphere. The structure of the aortal leaves wasvery observed in order to enable detection of even J Ai,a «adfi alteration in cell shape.
The plants studied were table beet, sugar beet, lettuce, spinach, Swiss chard, endive, oats, an 0. B» Hudd. The ability to catalyze the incorporation of these precursors declines as the preparations age. This deterioration is associated with the soluble enzymes, rather than the fragments of the chloroplasts.
Effects 'Plants awl Linstock the incorporation of acetate and nalcnate into lipid. At higher concentrations the sulfhydryl reagents inhibit the incorporation into non-volatile water soluble ccasfcunds. The inhibition by p-chloromercuribenzoate and cadmium ions can be reversed by reduced glutathione..
The inhibition by arsenite is enhanced by the presence of 2,3-dimercaptopropanol. Author summary S. Plants exposed to irradiated auto exhaust gases containing initially less than 0. The plants used in these studies were Poa annua and petunia, var. Rosy Horn. The symptoms observed were banding, necrosis, glazing, silvering, and cellular plasmolysis in substonatal regions.
Exposure time was 1 hour. Exposures were initiated at half bour intervals.. Poa annua was the most useful plant because of its greater range, simplicity of evaluation, and uniformity and also because a larger number of plants could be used in a given space.
The length of exposure required fcr the production of maximum damage appears to be related to the reaction rate of the fumigants, which depends in part on fuel bromine number and on the concentrations of the funigants. Differences in concentrations also produced marked differences in the degree of danage. Author abstract I. The test plants were grown tinder hydroponic conditions in a verniculite support medium containing prepared nutrient solution. The test plants were exposed to ambient air by circulating fans designed to provide one complete change of air volune every minute.
It was found that the flante were significantly »ore sensitive during the aid-porti t. BuXammal, and A.. Influxes of polluted air and attacks of tobacco weather fleck in southwestern Ontario were accurately forecast frcm the synoptic weather pattern and frost considerations of mesoscale neterological systems. The latter may empirically represent Physiological and physical factors affecting gas exchange.
A related downward flux of ozone night be important in determining the amount of ozone available for absorption. The subject of this paper is the damage air pollution does to the plants that, feed us, clothe us and please our aesthetic sense. This damage is considerable. Damage to vegetation has increased with industrialization and urban development,, several decades ago sulfur dioxide and fluorine were recognized as the principal plant toxicants.. These are products of atmospheric photochemical reactions between G, Effects-Plants and Umtock hydrocarbons and nitrogen oxides.
The principal products of these reactions are ozone and the peroxyacyl nitrates FANs. The distribution of plant damage in California shows that it occurs cnly in recognized geographical areas which, in each instance, are located within airsheds. The air contaminants responsible for damage nay be either particulate or gaseous in nature. The greatest amount of damage to animals and vegetation is usually caused by gaseous air contaminants which directly injure plants and indirectly injure animals by the toxic effects produced after the animal has consumed contaminated forage and food supplements.
Air quality affects plant growth and development. Whereas oxygen is necessary for aerobic plant respiration and carbon dioxide is necessary for photosynthesis in green plants, a number of pollutants nay alter plant metabolism and incite disease. It is the purpose of this paper to enumerate some of the principal air pollutants which adversely affect plant growth and reproduction, to describe the diseases incited by them, and to identify some of the problems of air pollution in phytopathological research.
A primary responsibility of the pathologist is to alert agriculturists of impending air-pollution problems, so that social action may be taken to insure the continued productivity cf crop, pasture, and forestry enterprises.
Another responsibility, because plants are early indicators of an air pollution problem, is to assist public health and resource agencies in the planning, conduct, and evaluation of air-pollution abatement programs. Plant pathologists must become increasingly concerned with the effects of air quality on plant growth.
Eight day old plants with or without cotyledons, are equally Managed by ozone and have the sane concentration of sugars. The relationship of this hypothesis to previous reports on ozone daaage tc plants is discussed with a view toward explaining the variability in observed daaage is the field as well as greenhouse studies..
Brady, V» Cu ed. Other topics discussed includes plant response as an indicator of aeteorological conditions and the fuels used for heat, light, and power. In: Agriculture and the Quality of Our Environaent. A review of the econcaic considerations of air pollution daaage to G.
Hence, the overall extrapolation is based on United data. The sources of information for previous accounts of damage exist only for geographically limited areas. These and other cases illustrate the weakness of this type of resolution of the problem of external diseconomy. In the United States, laboratory studies of sulfur dionide have generally been limited to acute effects that cause visible damage, little concern has been manifested for chronic effects, particularly if visible damage was not observed.
Only very recently, owing primarily to the stimulus of German research findings, has interest developed over chronic or growth effects.. There is also a possibility of a potentially greater nutritional threat to crops, which may not be currently reflected in market prices. Because the existing national estimates of crop damage have severe liiitaticns, a substantial underestimate may result from their focus on observed damage. Should the national estimates of crcp damage be needed, and they are needed for legislative and political considerations, there will inevitably be a long delay until reliable state and regional estimates on which they must be based can be prepared.
After years of careful study, sone of the coaponents of smog have been sorted out. The more important ones, their effects on vegatation, and a list of sensitive and resistant plants are discussed. The components are peroxyacetyl nitrate, ozone, ethylene, hydrogen fluoride, sulfur dioxide and aerosols.
M H. The damage done by air pollutants is costly both to farmer and consumer. Although there is no good aeasure of the total national loss froa air pollution, fugures have been published for soae localties. In Southern California, for exaaple, loses of vegetation due to oxidants are thought to be around 10 Billion dollars a year- This includes only the readily demonstrated loses of vegetable crops downgraded because of aarkings or left unpicked in the field.
The general conclusion is that air-pollution research in the field of agriculture a«st »ove ahead before a greater gap is created in this area. Six hundred healthy, 2-year-old seedlings were potted and taken to Morgan County, Tenn. After a year of exposure, of the trees had died, either froa handling, air pollution damage, or both. The regaining trees showed serious daaage, so they were returned to the recovery area in North Carolina.
After a year of exposure in Alabama, 15? The healthy trees were aoved to Beltsville, Hd. Although, the exposure period is not over, and final figures say be different, 13 trees have been injured and 13 still appear healthy. The results of these tests indicate there is enough genetic variation is a large eastern white pine population to provide biological indicators for specific toxicants.
Air pollution G. Plants developed typical ethylene- injury symptoas when fumigated for 21 to 48 hr with ethylene or various combinations of ethylene, acetylene, propylene and nitrogen dioxide. Khen propylene and nitrogen dioxide were included in the gas mixture and the mixture irradiated typical oxidant symptcns were recorded.
Slight to severe necrotic spotting, due to nitrogen dioxide, vas noted in a as hr fuaigation at one ppm nitrogen dioxide and in a 21 hr fuaigation at 3. Twelve hour fumigations using irradiated mixtures of ethylene, acetylene and propylene at three concentrations 2,t, and 8 ppa each in combination vith one ppa of nitrogen dioxide gave typical oxidant damage vith only the propylene-nitrogen dioxide mixtures..
From reported oxidant injury syaptoas the propylene-nitrogen dioxide irradiated mixture produced plant injury which is typical of both ozone and PAN. The presence of other phytotoxicants vas not dicounted hut the severity of injury, under the conditions used, made it difficult to evaluate other possible types of oxidant damage.
The effects of varying light and teaperature conditions during the fuaigation period indicated that plants must be in the light before they are sensitive to oxidant daaage and that a temperature above or below noraal will reduce oxidant injury. Results stress the need for studying the interrelations of oxidant injury and various environmental factors. Author"s sunoary C Brewer, B. Soil Sci. Several Mangel seed Burpee No.
The remaining nangels were placed in a duplicate fumigation chamber which received activated-carbon-filtered air to reaove aabient oxidants. At the end of 2 days, during which the one group of plants was exposed to two 6-hour fumigations vith an average organic oxidant concentration of 0»01 ppm.. Thirty-six hours after fusigation was stopped the plants were systematically examined tot incidence and severity of damage.
A siailar experiaent was conducted using spinach as the test flan. A statistical analysis of the aangel funigaticn data indicate that the severity of injury was wery significantly increased as the nitrogen level was increased. There were also highly significant interactions of nitrogen with phosphorus and between phosphorus and potassiua on severity of injury, "the results of differential fertilization on the sensitivity of spinach to ozone injury indi- cate that increasing the nitrogen supply very significantly in- creased both the incidence and the severity of ozone injury, fertilization on the sensitivity of spinach to ozone injury.
Freebairn and 0. Proc« la. The action of ozone on plant «nd aniaai aitochondria has been shown to be presented and by the addition of excess aaonnts of glutathione reduced fora ascorbic acid. Coaaercially-grown petunia plants were "is? Kendrick, Jrn, E. The most effective materials were dithiocarbaaates, mercaptcbenzothiozole and their derivatives while the least effective were amine derivatives.
The degree of protection was directly related to concentration of chemical, longevity of protection was related to accumulated periods of exposure to toxicants. Over a hour accumulated exposure period plants were significantly protected, although the degree of injury gradually increased with exposure tine.
In contrast, when several days lapsed between application and exposure, the chemical was as effective as when applied on the day of exposure, action of the protectant was local and net systemic; the toxicant appeared to be deactivated at the leaf surface.
Leaves remained free of injury only when the chemical was applied to the lower leaf surface and then only on that portion actually covered with chemical. Some degree of protection was achieved in field tests against atmospheric oxidants as well as against those generated in the laboratory. Sarley, J.. T» Middleton, and A.. Controlled experiments have also shown that plant response tc air pollution varies with species and variety of plant, age of plant tissue, soil fertility levels, soil moisture, air temperatures during the prefnaigation growth period, and presence of certain agricultural chemicals on leaves.
Plants also vary in their susceptibility to sulfur dioxide, with alfalfa, barley, and cotton damaged at comparatively low levels, and citrus, corn, celery, and melons daaaged at much higher levels, field observations show that young leaves are seldom narked during periods of aggravated air pollatioa. In grasses, where the youngest tissue i intensity of injury lujury first occurs at tip.
Several groups of ch oxidized capable of preventing injury to? Syaptoas of oxidant damage were usually aparent within four hours; however, assay of daaage was mada 48 hours after exposure to the oxidants. Sensitivity to ozone injury was increased by the low light intensity while sensitivity to peroxyacetyl nitrate was increased by the higher light intensity. In one series of experiaents, bean plants were fuaigated with very high concentrations of PAN for 10 ainutes.
Poroaeter measurements showed that the resistance to air flow through the stonates during the dark period was essentially unchanged This indicated that the observed results were related to the interaction of light and scae product in the plant and not to the exclusion of PAN by closed stonates.
Todd B. Flantarun 16, , Both fumigants caused Marked decreases in the rate of photosynthesis in all 3 species although in tonato and coleus leaves, the reduction in photosynthesis took place only during fuaigation with ozonated hexene gas and afterwards the rate returned to normal.
Ozone fumigation caused decreases in transpiration but the decrease was not as large as that obtained for photosynthesis. Transpiration in tomato and coleus leaves shoved little response to ozonated hexene gas although bean leaves responded in auch the sane way as they did when they were treated with ozone alone. A visual estimate was made of the amount of leaf surface damaged.
The visual-rating system appeared to be sensitive in the lower range of injury but rather insensitive at the upper end of the range. The visual- damage index appears to be logarithmic with respect to both chlorophyll and fresh-weight changes.
It was concluded that a measurement of the change in either fresh weight or chlorophyll content would give a better estimate of impairment of leaf function, since the visual-damage system tends to overestimate the flamage inflicted, particularly when only a small amount of leaf surface is involved. Air Pollation Control Assoc,. J The evidence in the present study on chlorophyll and pheophytin conversion in conifer leaves indicates that acid gases, such as sulfur dioxide in sufficiently high concentration, convert the chlorophyll pigments into the corresponding pheophytins- This process does not take place to an appreciable extent, however, unless the threshold values for sulfite in the living cells is exceeded..
The effect may be produced by either relatively short exposures to high concentration of gas or more prolonged exposures to lower concentrations. Transformation of an appreciable proportion of chlorophyll to pheophytin is accompanied by visible symptoms in the tissue, such as plasmolysis, shrinkage of cells, And fading of the normal green color.
Eventually such leaves turn brown because of post-mortem oxidative changes. These color G. Effects - Plants and Livestock changes are characteristic of conifecs. In other species, the destruction of the chlorophyll, pheophytin, and other pigments in the chlorcplasts results merely in the appearance of bleached or ivory colored areas, as in cereals and alfalfa.
In chlorotic injury the affected tissue is deficient in chlorophyll, but the extent of pheophytin conversion is not high, and such leaves may recover their normal functions if plasmolysis has not taken place. Prolonged exposure to sulfur dioxide below the threshold injurious concentration has no appreciable effect on the chlorophyll content of leaves, as shown by sample specinens from the inner and intermediate fume zones of a stelter area.
Deposits on leaves and in stomata from smoke and ether aerosol contaiinants in an urban environment may cause little, if any, discoloration but can result in a reduction in the normal chlorophyll level-M Richards, B. L«, Hiddleton, J. A study of ozone stipple of grape leaf shows that lesions on the upper leaf surface and premature leaf fall occur on grapevines in areas polluted by airborne ozone. The primary symptoms consist of small, brown to black, discrete, dot-like lesions, which are easily distinguished from the lesions of the other grape disorders because of the stippled appearance on the upper surface of the leaf..
The typical primary lesions vary in diameter from about 0. Large lesions result from coalescence of small ones, and may measure up to 2. Aggregates of these minute spot-like lesions produce the typical stipple appearance. Richards, J. Hiddletcn, and «- B. The lesions are typically restricted to the palisade layer and may be easily distinguished from other grape disorders because of their stippled appearance.
The disease can be incited in grape by fumigation with ozene. Toxic ozone levels occur in the polluted air mass above the Los Angeles and San Prancisco areas where oxidant stipple is found, stipple has not yet been seen in the grape producing areas in the Coacfaella, Napa, Sacraaento, and San Joaquin valleys of California.
Leaf injury to grape due to foliar fluoride accuiulaticn can be readily distinguished because it is marginal red to brown in color, necrotic, and commonly exhibits zonate markings.. Although ozone occasionally may cause leaf injury to some plants particularly grasses, grown in areas receiving naturally polluted air, it is unusual to note ozone damage to agricultural crops; oxidant stipple cf grape is, therefore, a unigue disease both in its symptcmology and etiology.
C, MacLean, D. McCune, 1. Weinstein, R. Mandl, G. Six citrus varieties and six ornamental species of economic importance to Central Flcrida were subjected to high concentration-short duration exposures of gaseous hydrogen fluoride HF or nitrogen dioxide N Pose-fumigation observations showed that the effects of acute pollutant exposures differ markedly from those of chronic exposures.
HF exposures of 0. Injury was most severe on, but not limited to, young leaves. The effect of duration of exposure had a greater influence on abscission of young citrus leaves than did HF concentration.
However, the effect of HF concentration on foliar F accumulation could not be separated from exposure time. N02 concentrations used ranged from 25 to ppa for durations of froo 10 minutes to 8 hours. N02 damage was characterized by rapid tissue collapse, necrosis, and defoliation.
Injury was sporadic in appearance, affecting leaves of all ages. The relative contributions or concentration and duration to Ninduced injury were about equal. Author abstract L. Crdin, M. Hall, B. Air Pollution Ccntrcl Assoc. Levels of PAN which inhibit oat ccleoptile section growth reversibly, severely inhibit metabolism of cellulose and of cell wall non-cellulosic polysaccharides.
An enzyme in the coleoptile cell walls which hydrolyzes some ot the non-cellulcsic glucan was partially inactivated by direct PAN treatment ot homogenized cell wall. Treatment of intact cells by PAN also resulted in a partially inactivated enzyme. Ccleoptile phosphoglucoautase was partially inactivated by treament with PAH both in vitro and in vivc.
After treatment of intact cells with PAN, phosphoglucomutase associated with subcellular particles was more severely inactivated than was soluble enzyme. Uridine diphosphate glucose pyrophosphotylase from coleoptiles was inactivated by PAN in vitro but not in vivo. A particulate cellulose synthetase from coleoptiles was inactivated by PAN both in vitro and in vivo.
Drummond, B. Wilhour, and D. In order to study the effects of photochemical air pollutants such as ozone and peroxyacetyl nitrate PAN on woody plants, a chamber was selected and aodified to provide a uniform concentration of fumigant throughout its interior, a high degree of control of temperature and relative humidity, a size large enough to accomodate five to ten-year old trees and interior components resistant to corrosion by oxidants.
Fluctuations in dry bulb temperature, wet bulb temperature, and ozone concentration at a given point in time were plus or minus F-plus or minus 1. Ivie, and B.. Air pollution is considered to be a aajor factor contributing to this problem. An industry-agriculture-local government-university sponsored, cooperative study entitled the Agricultural Air Research Program was begun in to assess the econonic effect of various air pollutants, principally oxidants and fluorides, on fruit yield, quality and tree growth- Measurements of photosynthesis and transpiration are used to supplement the longtime growth and yield observations.
Automatic data recording is provided for: 1 apparent photosynthesis by carbon dioxide exchange: themselves to the uptake of the oxidants or in the presence of reducing agents in the cell or, simply, less sensitive enzyme systems. It was found that intact seedlings in the gas stream are not more sensitive than sections flcating in water during gas exposure- The lack of illumination during exposure may also be a factor, since even sensitive petunia plants exposed in the dark to C.
The remarkable thing about these phytotoxicants is that each one severely affects a particular group of plants which is more or less tolerant to the other pollutants. Eor that reason plant indicators are very useful in diagnosing the specific gas or gases responsible for an air pollution episode, if observed during their optimum growth period.. Taylor, M. Thomas, and J.. The entire trees were enclosed in plastic covered greenhouses and were supplied various fractions of the atmosphere to find whether ozone, peroxyacyl nitrates, or fluorides were causing deleterious effects.
Nitric oxide was added to the air in one treatment to reduce ozone selectively but in so doing, nitrogen dioxide in amounts equal to the ozone was formed. The results showed that the total photochemical smog complex reduced the rate of water use by lemon trees and also reduced the rate of apparent photosynthesis. Fluoride levels occurring in the atmosphere caused no detectable effects- Attempts to evaluate the separate effects of ozone and peroxyacyl nitrates were unsuccessful.
Seduction of the ozone in the tree atmospheres by addition of nitric oxide failed to overcome the reduced water use and lowered apparent photosynthesis. Author abstract modified Seidman, Gabriel and Wilson B.
Ereprint, Dept. Effects-Plants and Livestock since the degree of stomatal opening may influence the arcunt of air pollutant injury, a year-long study or daytime stomatal movements was initiated, light, temperature, atmospheric pressure, relative humidity, time of day, and month or year were the parameters studied.
Atmospheric pressure was considered because it was felt that air pressure changes might affect the turgor ot the guard cells and thus change tbe size of the stomatal pore. Certified seeds of Phaseolus vulgaris, L. Pinto from stock stored at room temperature were planted in a standard peat-perlite mix and grown in the greenhouse and in the growth chamber.
Two plants were grown in each 4-inch plastic pet. The pots were placed in a pan of Hcagland's solution. Plants in five pets were started in the greenhouse, and an eyual number in the growth chamber each day. In the growth chamber light intensity, temperature, and photoperiod were held constant. If there were actually daily and yearly rhythms in stomatal opening as a result of photoperiod, temperature, or changes in light intensity only, no rhythms or a reduced rhythm in the growth chamber would be expected.
Stomatal movements in plants grown under variable greenhouse conditions as well as under constant growth chamber conditions appear to be subject to seasonal rhythms. Stomates of plants grown during the fall and winter months do not open as wide as those grown during the spring and summer months.
To determine if photochemical ait pollutants were present in Utah along the Wasatch front, ozone sensitive indicator plants Tobacco Bel-C and W-3 were grown at several locations in Utah, Salt Lake, and the southern part of Davis Counties and observed for injury development. These studies, which were conducted over a seven year period, shoved that extensive ozone injury developed on the indicator plants in the northern part of Salt Lake County and the southern part of Davis County.
Injury was less severe and developed less frequently in the northern part of Utah County, and injury was extremely rare in the southern part of Otah Count;. The authors were particularly interested in PAN measurements because atmospheric PAN concentrations have not been reported in the literature.
Results of these analyses are discussed in this paper. A "Bast" ozone analyzer that had been calibrated with potassium iodide was used to measure ozone in the aabient air at the laboratory. Peroxyacetyl nitrate was measured by the method of Parley et al. An electron capture detector mounted in the box and connected to the electrometer of a Villeins Model D gas chromatograph was used to determine the PAH concentration. Ozone vas measured sporadically during , and starting in June of continuous measurements have been made except for limited periods when the analyzer vas needed for other studies.
Two figures are included showing the monthly average ozone concentrations and the average hourly ozone concentrations for representative months. A comparison is also made of the ozone concentrations found in the areas. B refs. The leaves of untreated plants did not contain detectable anthocyanin. Furthermore, chlorosis did occur in treated plants. The anthocyanin was isolated from the leaves of saog treated plants, purified, and identified only as a cyanidin glucoside.
The amount of protection which vitamin C provided for plants against ozone and smog was investigated. In the laboratory, plants were treated with ascorbate salt by addition to the solution surrounding the roots of plants growing in water culture.
The plants were then fumigated with ppm of ozone for 2 hours. Poa annua plants growing in a greenhouse were sprayed with 0. Similar methods were used on other plants and flowers grown under glass. Lettuce and spinach plants growing commercially were sprayed in the field for one, two and five days per week with potassium ascorbate.
Smog attacks occurred about 20 days after spraying was initiated.. In these field tests no significant amount of protection was obtained for the spinach; G. In: Agriculture and the Quality of Our Environment. Brady, N. A review which cites examples cf injury to forests by specific ait pollutants.
The source and the nature of the pollutants are discussed. Also, the contribution of trees in conbating the air the rd» Meeting, American Association for the Advancement of pollution problem is speculated on. There is a considerable body of knowledge already available but it is dwarfed by the magnitude of what is not yet known. Kogure, ft. Takenobu, Takenobuv and P. J» Intern. J to unipolar ionized atmospheres of either charge at 21 deg..
C and 26 deg. C induced an earlier onset of hatching. Continued treatment of the larvae produced the following physiological effects: 1 A narked increase in the rate of larval growth; 2 Increased biosynthesis of catalase, peroxidase and cytochrome c oxidase; 3 Earlier onset of spinning; 4 A significant increase in weight of cocoon at 24 deg. At 24 deg. Exposure at both 2« deg- C and 26 deg.. C to air ions of either charge resulted in developsent of heavier silk layers but the increases were not statistically significant.
A variety of exposure chamber designs have teen used in the study of the effects of phytotoxic air pollutants on vegetation. Acceptability of a design is determined by the types of plants to be studied and the purpose of the research. In any exposure chanter, however, design is determined by the most desirable flow characteristics, the toxicants to be used, and the degree ot environmental control desired. A major consideration should be versatility combined with simplicity.
The chambers used in studies at the National Center for Air Pollution Control utilize a dynamic, negative-pressure, single-pass flow system with uniformity of flow, toxicant nixing, and distribution in the chamber. The simple design permits easy installation of numerous chambers in a single air-handling system while still permitting individual control of chambers.
Authors' abstract HI Bichards, B. Controlled fumigation studies and at the Citrus Besearch and Agricultural Experiment station, Biverside, Calif. Basic experimental research together with the wide range of field studies and observations by the present authors have clarified the type and sequence in symptom expression essential for diagnosis, and have greatly extended the range of pine species visibly susceptible to atmospheric ozone.
Additional emphasis is placed on significance both of the ozone needle mottle problem and of ozone as an economic factor in forestry. Science, : , April 6, Ataospheric ions, identified by Mobility characteristics, were associated with gemination of lycphilized uredospores of Puccinia striiforais Rest, at Bozenan, Montana. Ions of interaediate size were highest in concentration, and percentage gemination of spores was lowest during periods conducive to air pollution.
In duplicate experiments at an isolated site near Barrow, Alaska, essentially all ataospheric ions were snail ions and the fungus spores were consistently gerainated near aaxiaua. Tan and H. Translated fron Geraan.. The effect of N02 on plants was studied. Because NO is always present wherever there is NO was also introduced into the exposure chambers containing test plants.
Included in the tests were various dicotyledons, monocotyledons, conifers, and deciduous plants. Never give anyone else your mPIN or other security details. If you do not inform us, we will not be able to investigate and consider any request for compensation, if someone takes money from your account because they knew your account details 7. Always keep your cellphone or tablet secured through the use of a passcode.
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