Stem-rust-infected leaves of resistant (var. Khapli) and susceptible (var. Little Club) wheats were detached and floated on water and benzimidazole, with and without glucose. Khapli leaves were susceptible on water, resistant on 40 p.p.m. benzimidazole, susceptible on 40 p.p.m. benzimidazole with 1% glucose, and resistant on 60 p.p.m. benzimidazole with 1% glucose. Little Club leaves were susceptible in all treatments. Khapli leaves subjected to treatments that increase the endogenous substrate levels, such as floating on water for 2 to 4 days or spraying with DDT 2 or 3 days before detachment, were susceptible on 40 p.p.m. benzimidazole and resistant or partially resistant at higher concentrations.The progressive decrease in protein of detached leaves on water was interrupted on transfer to benzimidazole, after which some resynthesis of protein took place with a corresponding decrease in the soluble nitrogen fraction. Detached leaves on benzimidazole with 1% glucose had more soluble nitrogen than leaves on benzimidazole alone. There was more alcohol-soluble carbohydrate in leaves floated on water than in leaves on benzimidazole.

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