Influence of 2,4-Dichlorophenoxyacetic Acid on Pathways of Glucose Utilization in Bean Stem Tissues

2,4-Dichlorophenoxyacetic acid (2,4-D) is the best known selective herbicide for effective control of broadleafed weeds in monocotyledonous crops. Although the mechanisms by which 2,4-D acts on plants have not been elucidated, several lines of investigation have shown: A. Stimulatory and inhibitory effects on the respiration of pea and oat tissues, depending upon the concentrations employed (6). B. Reduction of bcarbohydrate content of bean stem (7). C. Increased participation of pentose cycle pathway of glucose catabolism in root tips of pea, corn, and oat seedlings (4). These results suggested that carbohydrate metabolism may be greatly effected. The present work is based upon the hypothesis that 2,4-D influences growth by affecting glucose utilization which furnishes the energy and/or building units for the synthesis of cellular constituents. This is approached by directly measuring utilization of radioactive carbon atoms from glucose in treated and untreated tissues after substantial morphological response has occurred. This paper reports the results from several experiments on the effect of 2,4-D on the pathways of glucose utilization in bean stem tissue using C14 labeled glucose.