Ozone injury

Koiwai, A., and T. Kisaki. Mixed function oxidase inhibitors protect plants from ozone injury. Agric. Biol. Chem. 37 2449-2450, 1973. 

Bystrum et al. first described morphologic changes in leaf surface waxes of table beet exposed to photochemical oxidants these changes were different from those associated with aphid feeding. Comparison of oxidant injury with that produced by insects has since received attention from Hibben, who found that ozone injury to the leaves of four tree species produced smaller flecks, randomly spaced and darker than fleck injury along veins induced by a mesophyll-feeding leafhopper. 

The most complete description of ozone injury symptoms is found in the Ar/os. However, several of the review articles, including the two criteria documents, have injury descriptions. A concise description is found in Heck and Brandt. ... 

It is currently impossible to give a rational explanation of the relationship between ozone injury and carbohydrate and nitrogen composition of the leaf. The compounds measured (protein and carbohydrate) may be only distantly related to metabolites that confer resistance or susceptibility. 

Ozone and sulfur dioxide mixtures are of special interest, because of their widespread occurrence and the greater than additive effect on Bel W, tobacco. Concentrations of either or both that may cause foliar injury are found around major metropolitan areas throughout the world and are widespread throughout rural eastern United States. Macdowall and Cole reported that the two-gas combination lowered the threshold for injury of tobacco (cultivar White Gold) by sulfur dioxide, but not the threshold for ozone injury. Macdowall et defined the threshold in terms of dose when th reported the threshold at 20 pphm-h (0.20 ppm-h). This has not appeared true in several other reports, nor within the results reported by Macdowall and Cole. Symptoms reported, when sulfur dioxide was below the threshold for the specific plant, were similar to those reported for ozone. 

An important factor in the response of vegetation to oxidants (primarily ozone) is the presence of biotic pathogens. Such responses have been studied from several perspectives since Yarwood and Middleton accidentally found that rust-infected bean leaves were less sensitive to photochemical oxidants (probably PAN). Several investigators have looked at the protection from ozone injury afforded to plants with active infections others have noted that ozone injury increases the sensitivity of plants to... 

Stark et o/. and Miller et reported that oxidant (ozone) injury to ponderosa pine predisposed the trees to later invasion by pine bark beeides. The beetles increase the rate of decline and may be the final cause of tree mortality (see Chapter 12). It is possible that oxidant stress in other parts of the country contributes to insect infestation in forest areas. Weber (personal communication) has shown that ozone and mixtures of ozone with sulfur dioxide (0.25 ppm, 4 h/day) can decrease the population of four nematodes associated with soybean. These... 

Larkin injected several peroxidases at 0.1-10 ppm into one-half of a tobacco leaf and found some protection. He suggested that peroxidase, which is often associated with plant stress conditions, may be important in physiologic resistance. It is doubtful that any one mechanism of action exists. It is important that we understand the mechanism of ozone injury and resistance in plants, so that we can determine better what chemicals may play a role in protecting plants against oxidants. 

Craker, L. E., and J. S. Starbuck. Metabolic changes associated with ozone injury of bean leaves. Can. J. Plant Sci. 52 589-597, 1972. 

Curtis, L. R., L. V. Edgington, and G. Hofstra. Relationship of ozone injury to time of application of carboxin analogues. Phytopathology 63 200, 1973. (abstract)... 

Gardner, W. S. Ozone injury to tobacco plants in South Dakota. Plant Dis. Rep. 57 106-110, 1973. 

Howell, R. K., and D. F. Kremer. Ozone injury to soybean cotyledonary leaves. J. Environ. Qual. 1 94-97, 1972. 

Kadota, M.. and K. Ohta. Ozone sensitivity of Japanese plant species in summer, with special reference to a tentative sensitivity grade list for applying to field survey on ozone injury. Taiki Osen Kenkyu (J. Jap. Soc. Air Pollut.) 7 19-26. (in Japanese, summary in English)... 

Keen, N. T., and O. C. Taylor. Ozone injury in soybeans Isoflavonoid accumulation is related to necrosis. Plant Physiol. 55 731-733, 1975. 

Magdycz, W. P., and W. J. Manning. Botrytis einerea protects broad bean against visible ozone injury. Phytopathology 63 204, 1973. (abstract)... 

Manning, W. J., W. A. Feder, P. M. Papia, and I. Perkins. Influence of foliar ozone injury on root development and root surface fungi of pinto bean plants. Environ. Pollut. 1 305-312, 1971. 

Pellissier, M. Effect of Foliar and Root Treatments of Benomyl in Reducing Ozone Injury to Pinto Bean and Cucumber. (Center for Air Envirmunent Studies PuU. 213-71) M. S. Thesis. University Park Pennsylvania State University. 1971. 49 pp. 

Pellissier, M., N. L. Lacasse, and H. Cole, Jr. Effectiveness of benomyl and benomyl-folicote treatments in reducing ozone injury to pinto beans. J. Air Pdlut. Control Assoc. 22 722-725, 1972. 

Reinert, R. A., and H. W. Spurr, Jr. Differential effect of fungicides on ozone injury and brown spot disease of tobacco. J. Environ. Qual. 1 450-452, 1972. 

Runeckles, V. C., and H. M. Resh. The assessment of chronic ozone injury to leaves by reflectance spectrophotometry. Atmos. Environ. 9 447-452, 1975. 

Seem, R. C., H. Cole, Jr., and N. L. Lacasse. Suppression of ozone injury to Phaseolus vulgaris Pinto III with triarimol and its monochlorophenyl cyclohexyl analogue. Plant Dis. Rep. 56 386-390, 1972. 

Taylor, G. S. Ozone injury on Bel W-3 tobacco controlled by at least two genes. Phytopathology 58 1069, 1968. (abstract)... 

Taylor, G. S., and S. Rich. Ozone injury to tobacco in the field influenced by soil treatments with benomyl and carboxin. Phytopathology 64 814-817, 1974. 

Tomlinson, H., and S. Rich. Relating lipid content and fatty acid synthesis to ozone injury of tobacco leaves. Phytopathology 59 1284-1286, 1%9. 

The direct effects of ozone on plant species constituting the shrub layer in the conifer forest are not yet sufficiently understood to permit any conclusion to be drawn. In many sites where the conifer overstoiy is well developed, the shrub species are excluded completely. In more open pine stands, some shrubs are very common, such as skunk bush iAmorpha califomica) and white horn (Ceanothus cordulatus). Of these two species, only skunk bush shows highly visible chlorotic mottle of leaflets and premature defoliation where ozone dosages are high. A shrub species common to the lower chaparral zone, squaw bush Rhus trilobata), is even more susceptible to ozone injury. In the San Bernardino Moun-... 

The effect of ozone injury on herbaceous plant reproduction has been mentioned earlier in this chapter and in Chapter 11. Seed production by annuals is influenced mainly by the envirorunental conditions of the current year, but perennial woody plants—particularly conifers—are erratic seed-producers. Intrinsic factors affecting cone production include age and vigor seasonal temperature and soil moisture are important environmental factors. ... 

The effects of sulfur dioxide on cone production have been described by Scheffer and Hedgcock and Pelz. Generally, the decrease in tree vigor caused by the pollutant may eliminate or lower the frequency of cone production and diminish the size, weight, and germination of seed. The effects of chronic ozone injury on conifer seed production may be similar, in that tree vigor is drastically reduced. The effects of chronic ozone injury on ponderosa and Jeffrey pine seed production are under investigation by Luck (in Kickert et al,... 

California black oak and white fir and less often on incense cedar in the San Bernardino Mountains. No direct effects of oxidants have been noted on the mistletoe plant itself under field conditions. The true mistletoe obtains mainly water from its host and would be indirectly affected by debilitation of die host tree. The dwarf mistletoes Arceuthobium spp.) are common on ponderosa, Jeffry, and sugar pines in the San Bernardino National Forest. They depend on their host for both water and carbohydrates. Heavily infected or broomed" branches on ponderosa or Jeffrey pines severely injured by ozone often have more annual needle whorls retained than do uninfected branches on the remainder of the tree. The needles are also greener. It can be hypothesized that the infected branch is a carbohydrate sink where a pooling of carbohydrates occurs higher carbohydrate concentrations may be instrumental in either preventing or helping to repair ozone injury to needles on the broomed branches. In the long term, stresses from mistletoe and ozone are probably additive and hasten tree death. 

Ozone injury limits biomass production by the primary producers and their capacity to reproduce. 

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