Ozone Effects on Plant Cell Permeability

Abstract

The effect of ozone on plant cell permeability was examined. Pinto bean plants (Phaseolus vulgaris) were exposed to 0.4 ppm ozone for one hr and discs cut from primary leaves were allowed to take up /sup 14/C-UL-d-glucose or /sup 14/C-UL-2-deoxy-d-glucose. Uptake of 2-deoxy-d-glucose one hr after exposure appeared lower in exposed tissue than controls, while 24 hr after exposure uptake of both sugars by exposed tissue was three times that of controls. When uptake in one hr was examined at various times after exposure up to twenty hr it was found that permeability did not increase until several hr after the end of exposure. Cursory examination of the internal distribution of /sup 14/C label showed that the increase in permeability was not a function of increased metabolic activity since no differences were seen between exposed and control tissue, except in fractions representing cell wall material. The same percentage of /sup 14/CO/sub 2/ was released by exposed and control tissue even though uptake of glucose was greater in exposed tissue. These data are interpreted to mean that the primary targets for ozone are cellular membranes, resulting in alterations in membrane permeability.