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OZONE SENSITIVITY OF LEAVES: RELATIONSHIP TO LEAF WATER CONTENT, GAS TRANSFER RESISTANCE, AND ANATOMICAL CHARACTERISTICS
Author(s) -
Evans Lance S.,
Ting Irwin P.
Publication year - 1974
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1974.tb12280.x
Subject(s) - ozone , biology , water content , limiting , botany , horticulture , chemistry , mechanical engineering , geotechnical engineering , organic chemistry , engineering
Relative water content, resistance to gas transfer, stomatal spacing, and other characteristics of primary bean leaves were studied in relation to ozone sensitivity and injury. Cells of primary bean leaves are maximally sensitive to ozone exposure 9–10 days after germination under our experimental conditions. The stage of maximum sensitivity was not correlated with changes in stomatal number or resistance on either adaxial or abaxial leaf surfaces. It was deduced that bean leaf sensitivity was a function of more internal circumstances, and gas exchange was never the limiting factor through the developmental period studied. Changes in resistance were not significantly altered by ozone levels that produced no visible injury. After exposure to high ozone doses, a decrease in adaxial resistance occurred apparently as a result of palisade and epidermal cell lysis. Normally most gas exchange occurs through the adaxial surface. A 10 % decrease in relative water content accompanying a 60‐min ozone exposure of 0.55 ppm could not be explained physiologically on the basis of cell injury as no visible leaf injury occurred.