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The Effects of Low Concentrations of Sulphur Dioxide on Stomatal Behaviour in Vicia faba
P. V. Biscoe, M. H. Unsworth and H. R. Pinckney
The New Phytologist
Vol. 72, No. 6 (Nov., 1973), pp. 1299-1306
Stable URL: http://www.jstor.org/stable/2431491
Page Count: 8
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The stomatal resistance of leaves of Vicia faba L., measured using a diffusion porometer, rapidly decreased when plants were exposed to air containing SO2. The stomatal resistance decreased by 20% for the SO2 concentrations used (140, 290 and 1430 μ g m-3) and the minimum concentration to which stomata responded was 72 μ g m-3. Although stomatal resistance increased with leaf age, when exposed to 290 μg-3 SO2, the opening response was larger and more rapid in the older leaves. Exposure to 290 μ g m-3 SO2 throughout a day suppressed the normal diurnal variation in stomatal behaviour and reduced the stomatal resistance by 25%. It was estimated that the measured stomatal responses to SO2 would increase the transpiration rate by 32% for single leaves in a growth room and by 23% for a field crop.
The New Phytologist © 1973 New Phytologist Trust