Effect of 2,4-dichlorophenoxyacetic acid on utilization of labeled acetate by bean leaf & stem tissues

Publisher Website
Google Scholar
Abstract
In vitro studies on the utilization of acetate by bean leaf and stem tissues were carried out using C14 labeled acetates (sodium acetate-1-C14 and sodium acetate-2-C*4). The stem tissues from bean plants receiving 50-150 [mu]g 2,4-D/ plant showed a twofold increase in substrate absorption, a three- to fourfole increase in catabolic activity as indicated by radiochemical yield of respiratory C14O2, and no significant change in synthetic activity as indicated from isotope incorporation into alcohol insoluble residue. Free acetate was accumulated in 2,4-D treated stem tissues that could have resulted from an increase of substrate uptake with no (slight) increase of metabolic activity. The formation of lipids by multiple [beta]-condensation of acetate was not affected in 2,4-D treated stem tissues while by other pathways it was increased. The effects of 2,4-D on both catabolic and synthetic functions of acetate utilization in bean leaf were slight and dependent on the dosage used. At 10 u[mu]g/plant a decrease of catabolic function and a greater increase of synthetic function were observed for C-1. The influence for C-2 was negligible at this level. At 20 and 50 [mu]g 2,4-D/plant, a 35-40% increase for C-l utilization was evident. The increase for catabolic utilization of C-2 carbon was approximately 70%, while for synthetic function it was 20-25%.