The ethyl ester of fenoxaprop [(±)-2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoic acid] applied to the foliage of corn resulted in a decrease in shoot fresh weight with each increase in herbicide concentration used, with no subsequent effect on root growth measured 96 hr after treatment. Root-applied fenoxaprop inhibited root growth 49% at a concentration of 2.5 μM. Total free amino acid content in treated tissue with 5 × 10-3 M fenoxaprop (336 g ai/ha) for 96 hr increased 84% when compared with that in untreated tissue. Increases of 225 and 522% were recorded for histidine and arginine, respectively, while alanine, isoleucine, serine, and phenylalanine increased at least 100%. DNA content of corn increased 62% when foliar treated with a 5.0 × 10-3 M concentration of fenoxaprop. Fenoxaprop at a concentration of 10-5 M reduced indole-3-acetic acid-induced elongation of first internode sections 29%. Based on these data, fenoxaprop appears to be an auxin antagonist resulting in an accumulation of cellular compounds such as DNA and amino acids.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Health, Toxicology and Mutagenesis