Studies on the Mechanism of Injurious Effects of Toxic Gases on Crop Plants : IV. Effects of sulfur dioxide on respiration of rice plants

[摘要] This experiment was undertaken to determine the effect of sulfur dioxide on the respiratory rate both at the seedling and at the highest tillering stages of rice plants. The respiratory rate was measured in the laboratory under a controlled temperature of 30°C, exposing the plants to various concentrations of SO2, which were determined by a SO2-analyzer of self recording system. The results obtained were as follows: 1. The respiration rate of rice seedling decreased linearly with increasing concentration of SO2. 2. The respiratory rate of rice seedlings was suppressed by the treatment of SO2 for one hour at a concentration of 60 ppm, showing no recovery after the gas removed. At the concentrations of 1, 4 and 10ppm the seedlings responded intricately, as seen in fig. 3. 3. The respiration rate at the highest tillering stage of rice plants was accelarated by exposing the plants to SO2 at the concentrations of 1, 5, 10 and 15ppm, respectively. By the treatment of SO2 at the concentrations of 40 and 60 ppm, it was always retarded. As the treatment hour was prolonged, the concentration of the gas effective to acceralate the respiration rate was declined. 4. As to the accumulated value for 4hours, the respiration rate increased linearly with increasing concentration of the gas. It showed the highest value at about a concentration of the 5 ppm, thereafter declining with increasing concentration of the gas. 5. From the above-mentioned facts it was suggested that both an increse and a decrease in the respiration of rice plants treated by the gas may lead them to decrease in dry matter production.

[学科分类] 农业科学（综合）