EFFECT OF BENZIMIDAZOLE, DIMETHYLBENZIMIDAZOLE, GLUCOSE, AND METAL IONS ON THE DEVELOPMENT OF PUCCINIA GRAMINIS TRITICI ON DETACHED LEAVES OF KHAPLI WHEAT

Abstract

Leaves of Khapli wheat which are normally resistant to race 15B-1 of Puccinia graminis tritici become susceptible when detached and floated on water. This breakdown of resistance can be reversed by floating the detached leaves on a solution of benzimidazole. The effect of benzimidazole, however, can be nullified by a supply of exogenous glucose or 5,6-dimethylbenzimidazole. Furthermore, the resistance can again be restored by the presence of cobalt ion combined in solution with glucose and benzimidazole or with glucose and 5,6-dimethylbenzimidazole. Cobalt ions alone, or in combination with glucose, or with benzimidazole, or with 5,6-dimethylbenzimidazole separately have no effect on rust development. In contrast, nickel ion alone or in any combination has a profound inhibitory effect on the development of rust in detached leaves. Other chemicals were also included in this study, and their effect on rust development is discussed. It is speculated that benzimidazole or a derivative of it and cobalt may form a vitamin B₁₂-like factor which is required by the host to maintain its normal metabolic activities.