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Effects of sulphur dioxide on leaf photosynthesis: the role of temperature and humidity
Author(s) -
Kropff M. J.,
Smeets W. L. M.,
Meijer E. M. J.,
Zalm A. J. A.,
Bakx E. J.
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb05693.x
Subject(s) - photosynthesis , fumigation , humidity , chemistry , vicia faba , relative humidity , carbon dioxide , horticulture , botany , biology , meteorology , biochemistry , physics , organic chemistry
The effect of temperature and humidity on SO 2 –induced photosynthetic depression was determined in gas exchange experiments with leaves of Vicia faba , L. Stomatal behaviour was sensitive to humidity resulting in higher uptake rates of SO 2 and stronger reductions of photosynthesis at low VPD (vapour pressure deficit). After a fumigation period of 2 h, when the photosynthetic rate had stabilized, photosynthesis of leaves exposed to SO 2 at 8°C was reduced much more than at 18°C at the same rate of SO 2 uptake. Data analysis with a mechanistic model revealed that this effect was due to the slower rate of S(IV) oxidation at lower temperatures, resulting in higher accumulation of S(IV) and thus stronger reduction of photosynthesis. These results were confirmed by experimental analyses of the S(IV) concentration in leaves following fumigation, which showed that more S(IV) accumulated in leaves exposed at a lower temperature. This may explain the high sensitivity of plants exposed to SO 2 under winter conditions, when both VPD and temperature are low.