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Response of Plants to Air Pollutants. III. A Relation between Ascorbic Acid Levels and Ozone Susceptibility of Light-Preconditioned Tobacco Plants

1964; Oxford University Press; Volume: 39; Issue: 4 Linguagem: Inglês

10.1104/pp.39.4.564

1532-2548

H. A. Menser,

Light effects on plants

The effects of prefumigation light regimes on plants indicate that light modifies the response of plants to ozone. Taylor et al. (11) reported that ozone injury to Pinto bean was reduced when plants were grown at the higher level of 2 light intensities. Menser et al. (7) found that ozone damage to tobacco plants was diminished by an extended 22-hour photoperiod immediately before fumigation. Ascorbic acid is known to protect plants from ozone and other oxidizing agents. Freebairn (3) increased the tolerance of Pinto bean plants to ozone either by supplying ascorbic acid to the roots or by foliar applications. Freebairn and Taylor (4) made tissue analysis of smog-sensitive plants sprayed with ascorbic acid. They found that concentrations of ascorbic acid in the leaves increased and resulted in partial to complete protection from air-pollution injury. This paper presents results of a study to determine the effects of light preconditioning on ascorbic acid levels in tobacco plants; and the relation of ascorbic acid levels to ozone injury of 2 tobacco varieties, one resistant and the other sensitive to ozone. Ascorbic acid concentrations reported represent the excess formed in synthesis over that utilized in metabolism. The results show that light preconditioning caused notable differences in ascorbic acid levels. These differences were associated with changes in the degree of ozone injury.