Varietal Differences of Sulfur Dioxide on Apparent Photosynthetic Rate in Rice Plants

Invisible injury caused by air pollution is known to make photosynthesis decrease，The purpose of this investigation was to make clear The effects of sulfurdioxide on rice plants. Sulfur dioxide (SO D22 - D2 was supplied at the rate of2.6mgSD D22 D2m d -3 d - 1 (about 1.0ppmv/v) for 15 min. and then displaced with clean air for 60min. SO - D22 - D2 on apparent photosynthetic rate was judged by three indicators were inhibitionratio,recovery ratio and Co - D22 - D2 fixation ratio. it was investigated to make a proper SO - D22 - D2 fixation ratio. it wastreatment that was the reaction of SO - D22 - D2 on apparent photosynthetic rate in rice plant （cv.）Koshihikari, Japanese major variety) at some condition (individual plant or leaf blade, age，treatment time, treatment part and so on). As a result这是一个很好的条件at the 10th day after booting stage using leaf blade in comparison with some14 cultivars in rice plant which breeding year was from 1882 to 1984 was researched on 3indicators by SO D22 D2 treatment extend two years. In all plants，apparent photosynthetic rate was depressed by the application of sulfur dioxide. Inhibition ratio in3 indicators was fitted for varietal differences on SO D22 D2 treatment.Inhibition ratio whichwas the magnitude of the depression in apparent photosynthesis observed in the following order：old cultivars (cv. Kyotoasahi Kamenoo, Aikoku) > new cultivars (cv. Hatsuboshi, Akitakomati，koshihikari)。

Invisible injury caused by air pollution is known to make photosynthesis decrease, and thus yields decrease. The purpose of this investigation was to make clear the effects of sulfur dioxide on rice plants. Sulfur dioxide (SOィイD22ィエD2 was supplied at the rate of 2.6mgSDィイD22ィエD2mィイD1-3ィエD1 (about 1.0ppmv/v) for 15 min. and then displaced with clean air for 60 min. SOィイD22ィエD2 on apparent photosynthetic rate was judged by three indicators were inhibition ratio, recovery ratio and CoィイD22ィエD2 fixation ratio.It was investigated to make a proper SOィイD22ィエD2 treatment that was the reaction of SOィイD22ィエD2 on apparent photosynthetic rate in rice plant (cv. Koshihikari, Japanese major variety) at some condition (individual plant or leaf blade, age, treatment time, treatment part and so on). As a result, it was good condition at the 10th day after booting stage using leaf blade in comparison with some cultivars.14 cultivars in rice plant which breeding year was from 1882 to 1984 was researched on 3 indicators by SOィイD22ィエD2 treatment extend two years. In all plants, apparent photosynthetic rate was depressed by the application of sulfur dioxide. Inhibition ratio in 3 indicators was fitted for varietal differences on SOィイD22ィエD2 treatment.Inhibition ratio which was the magnitude of the depression in apparent photosynthesis was observed in the following order : old cultivars (cv. Kyotoasahi Kamenoo, Aikoku) > new cultivars (cv. Hatsuboshi, Akitakomati, Koshihikari).