温州ミカンの亜硫酸ガス障害に対する各種薬剤の影響とその作用機作について

抄録

The influence of Bordeaux mixture and various kinds of chemicals on sulfur dioxide gas injuries of Satsuma orange were studied.
1. Rate of fallen leaves and rate of smoke-lesion leaves in the Bordeaux spray decreased more than the unsprayed ones during the first 8 days with fumigation of 3 ppm for 2 hours each day. But the injuries of Bordeaux spray increased more than the unsprayed by following with a higher concentration of sulfur dioxide. Then, promotion of sulfur dioxide injuries by Bordeaux mixture would be caused not only by precipitation as reported previously, but also by higher concentration of sulfur dioxide after a long term fumigation of low concentration.
2. Bordeaux mixture had a tendency to decrease the absorption of radioactive sulfur dioxide, and copper sulfate, which is the component of Bordeaux mixture also decreased the absorption of sulfur dioxide. Because lime oxide did not have a clear influence on sulfur dioxide injuries and copper sulfate had severe influence on the leaf fall of Satsuma orange, the additional effect of Bordeaux mixture on the sulfur dioxide injuries would be caused mainly by copper ion.
3. Difolatan (n-tetrachloroethylthio-4-cyclo-hexene-1, 2-dicarboximide) and Dithane (zinc ethylenbisdithiocarbamate) could be used safely in place of Bordeaux mixture. Fussol (monofluoroacetamide), which is insecticide, decreased greatly sulfur dioxide injuries. OED Green (oxyethylenedecosanol), which is retardant for transpiration, also decreased sulfur dioxide injuries.
4. The results of experiments on retardant of sulfur dioxide injuries showed that chemicals which promoted photosynthesis such as glutathion and ascorbic acid tended to increase the injuries due to higher concentration of sulfur dioxide. On the contrary, chemicals which suppressed photosynthesis such as Fussol and Dithane, decreased the injuries due to higher concentration of sulfur dioxide.