Residual Effects of Diuron [3-(3,4-Dichlorophenyl)-1,1-Dimethylurea] on the Sugar Content and Sugar-Metabolizing Enzymes of Ratoon Sugarcane 25 Months Following Different Soil Treatment

Abstract

A series of sugar and enzyme analyses were conducted with 5- to 6-month-old ratoon sugarcane to study the residual effects of Diuron upon certain sugar metabolizing systems. The cane represented the first ratoon crop growing on a Mabí clay soil treated 25 months previously with the equivalent of 2, 4, and 8 pounds per acre of Diuron. Total leaf ketoses and sucrose were significantly suppressed by 4 and 8 pounds per acre Diuron. Sheath sugars and percentage of sucrose of the juice and cane were only slightly affected by the herbicide. The activity of a number of critical enzymes was significantly altered by Diuron. These included maltase, hexokinase, glucose-6-phosphatase, fructose-6-phosphatase, glucose oxidase, transaminase, l-amino acid oxidase, and catalase. The nature of these variations and their possible consequences to the cane physiology are discussed in detail.