Abstract
A new soil fungicide with plant growth-regulating activity, S-(4-methylsulfonyloxyphenyl) N-methylthiocarbamate(methasulfocarb, Kayabest®, NK-191), promoted the elongation of rice seedling roots in water culture. Especially at a rate from 3.2 ppm to 12.8ppm the root elongation was remarkably accelerated. α-Naphthylamine oxidation of the rice seelding roots increased with an soil application of methasulfocarb 10% dust at a rate from 9mg to 720mg a. i. per 500ml soil before seeding. In the experiment using the rice seedlings exposed to a temperature of 5°C for 2 days, α-naphthylamine oxidation activity was stronger in the seedlings in methasulfocarb treated soil at a rate of 80mg a. i. before seeding than in those in untreated soil. The chlorophyll in the 2nd and 3rd leaves increased as methasulfocarb was applied at a rate from 160mg to 400mg a. i. The degradation of chlorophyll in the 3rd leaves reduced with the application of methasulfocarb at a rate of 80mg a. i. Water loss of the detached 3rd leaf increased with application of methasulfocarb at a rate of 80mg a. i. The results suggested that stomatal aperture of the leaves from the soil treated with methasulfocarb was wider than that of the leaves from the soil untreated.
