Effects of Inabenfide on the Formation of Branch Roots in Rice Plants (Oryza sativa L.)

Abstract

Two separate effects of Inabenfide on the formation of branch roots in rice plants (Oryza sativa L.) were investigated, using a special apparatus constructed with a Wagner pot (1/2000 a) divided into five compartments. Rice, cv. 'Koshihikari', was grown in the centrally situated porous stainless steel cylinder and, after treatment, roots were made to grow into four equivalent outer sectors. In the treated pots, one sector was untreated and the other three sectors were treated with Inabenfide (5% Seritard-granule 5^(R)) in different concentrations and then compared to the untreated pots. A remarkable increase was seen in the total length of branch roots per primary root and per unit length of primary root in the untreated sector of the treated pots as well as in the treated sectors of the same pot. In this case, the relative ratio estimated for the increase in the untreated sectors of the treated pots compared to the untreated pots marked a positive value. On the other hand, when the effect of Inabenfide that may affect the place of application was evaluated by comparing the treated and untreated sectors in the treated pots, the relative ratio against the untreated pots marked negative values. A contrary phenomenon was observed in the case of root dry weight per unit length of total roots. Consequently, it was indicated that although Inabenfide inhibits the growth of branch roots directly in the treated soil, it promotes the growth indirectly in the other parts of the application. As the sum of these opposing effects, the overall promotion throughout the root system observed in the previous study might be realized.