Studies on the Mechanism of Injurious Effects of Toxic Gases on Crop Plants : VIII. Symptoms of injury and stomatal apertures of tulip plant exposed to sulfur dioxide and hydrogen fluoride

[摘要] Experiments were undertaken to investigate an injurious effects of sulfur dioxide and hydrogen fluoride in the atmospheres on stomatal apertures of tulip plants of flowering stage. Typical symptoms of injury caused by sulfur dioxide and hydrogen fluoride on tulip plants were observed during and after treatment. Stomatal measurements were made from silicone impressions. All fumigations with closed system were made in the same chamber. The results obtained were as follows: 1. Injuries by lOO ppm of sulfur dioxide and hydrogen fluoride were observed on leaf, floral axis and petal of tulip plant, especially whole leaves being severely damaged in the concentration. White color was a typical symptom of leaf injury caused by lOO ppm of these gases. A relative resistance in each part of the fumigated plant was in thc following order: floral axis > petal > leaf 2. Injuries at concentrations of 30 ppm and below of these gases were observed only on leaf. It was observed that tip and nlarginal part of leaf appeared by the injury with the change of color from green to white color by concentrations of 30ppm and below of sulfur dioxide and with the change of color from green to greyish brown color by concentrations of 30 ppm and below of hydrogen fluoride: and soon thc injured part was spread to the central part of the leaf with increasing concentration of toxic gases or the extension of treatment time. From the above-mentioned facts, we can macroscopically distinguish the injuries by sulfur dioxide from these by hydrogen fluoride by the difference in changed color of the injured parts. 3. In tulip plants, a signiftcant difference in the susceptibility was observed between the injury of sulfur dioxide and hydrogen fluoride. The susceptibility of leaf to sulfur dioxide was more sensitive than to hydrogen fluoride. 4. The symptoms of leaf injuries by spraying solution of hydrogen fluoride to tulip plant appeared by the change of color from green to greyish brown color, but not symptorn appeared by spraying solution of sulfur dioxide. 5. From the result of estimation of stomata number in the position and the portion of leaf, it was suggested that higher susceptibility of the leaf than that of the floral axis was due to greater number of stomata per unit area of the former. 6. The injury-symptom in a leaf developed gradually from the tip to the central and base portions. This fact may also be related to the greater number of stomata per unit area in the leaf tip, hence with higher content of sulfur absorbed, than the other portions of the leaf.

[学科分类] 农业科学（综合）