ダイコンの赤心症発生に及ぼす硫酸カルシウムおよび硫黄華施用の影響

Abstract

Experiments were conducted to examine the effects of sulfur-containing chemicals on the incidence of internal browning, the polyphenol concentration, and the oxidase activity in Japanese radish.Application of either 4080 kg•a-1 calcium sulfate or 416 kg•a-1 sublimed sulfur tended to reduce the occurrence of internal browning and at the same time enhance the sulfur content of roots. In the latter treatment, the concentration of polyphenol and the polyphenol oxidase activity were reduced.Applications of calcium sulfate resulted in an increase in S and Ca in the roots, whereas, incorporation of super phosphate increased P content but lowered polyphenol oxidaseactivity.The addition of slaked lime to the sublimed sulfur not only failed to reduce the soil acidity, but it also induced internal browning and decreased sulfur content of roots. Increasing the level of calcium in roots via application of calcium carbonate did not alleviate the incidence of internal browning. These results suggest that the inhibition of internal browning was caused by the increased level of sulfur in roots rather than that of calcium.