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Physiological effects of sulphur dioxide. 1. The effect of SO 2 on photosynthesis and stomatal regulation of Vicia faba L.
Author(s) -
KROPFF M. J.
Publication year - 1987
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11604762
Subject(s) - photosynthesis , fumigation , vicia faba , transpiration , chemistry , carbon dioxide , botany , horticulture , biology , organic chemistry
. The effect of short‐term SO 2 fumigation on photosynthesis and transpiration of Vicia faba L. was measured at different irradiances and SO 2 concentrations. At high irradiances photosynthetic rates were reduced when leaves were exposed to SO 2 and the magnitude of the reduction was linearly related to the rate of SO 2 uptake through the stomata. Photosynthetic rates stabilized within 2 h after the start of fumigation. The effect of SO 2 on photosynthesis was measured at different CO 2 concentrations to analyse the contribution of stomatal and non‐stomatal factors to photosynthetic inhibition. Mesophyll resistance to CO 2 diffusion increased as a result of SO 2 exposure and caused a rapid reduction in photosynthesis after the start of fumigation. Stomatal resistance was not affected directly by SO 2 fumigation, but indirectly as a result of a feedback loop between net photosynthesis and internal CO 2 concentration. Analysis of gas‐exchange measurements in biochemical terms indicated that photosynthetic inhibition during SO 2 exposure can be explained by a stronger reduction in the affinity of RBP carboxylase/oxygenase for CO 2 than for O 2 .