Sulfur dioxide inhibition of photosynthesis at different CO2 and O2 concentrations in relation to photorespiration |
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| Authors: | Minoru Yamauchi Won Kae Choi Yoshio Yamada |
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| Affiliation: | 1. Plant Physiology Department , The International Rice Research Institute , Los Ba?los , Laguna;2. Jinju National Agricultural and Forestry Technical College , Korea;3. Department of Agricultural Chemistry , Kyushu University , Fukuoka , Japan |
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| Abstract: | ![]()
The mechanism of SO2 inhibition of photosynthesis in intact leaves of tomato and maze was studied to evaluate SO2 inhibition of photorespiration. Leaf tissues were fumigated with SO2 under photorespiratory (low CO, and/or high O, concentrations) and non-photo-respiratory conditions. When tomato leaf disks were fumigated with 10 ppm SO2 at 2, 21 and 100° o O., SO2 inhibited photosynthesis at 2% O2 in the same degrees as at 21% O2. SO2 inhibition of photosynthesis was depressed at higher CO2 concentrations when the disks were fumigated with SO2 at different CO2 concentrations. High CO2 concentrations also reduced the photosynthesis inhibition of maize leaf disks. These results suggest that SO2 inhibits photosynthesis through other mechanisms than photorespiration inhibition and confirm the view that SO2 competes with CO2 for the carboxylating enzymes in photosynthesis |
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| Keywords: | CO2 maize O2 photorespiration photosynthesis SO2 tomato |
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