Effect of an auxin-like herbicide 2,4-dichloro phenoxy acetic acid on proline content of mesquite (Prosopis juliflora Swarz) DC

Abstract

2,4-dichloro phenoxy acetic acid (2,4-D), known as auxin-like herbicide or synthetic auxin, mimic the effect of the natural auxin indole-3-acetic acid (IAA). Afield and laboratory experiments were arranged to study the effect of (2,4-D) on the proline content of leaves of natural stand mesquite trees (Prosopis juliflora) treated with 2,4-D at different rates (0, 6×103, 12×103, 18×103 and 24×103 mg a. i. / L). Herbicide rates dissolved in two solvents (diesel or water), which 2,4-D mixtures sprayed around the lower part of the tree stem. The experiment designed in the factorial experiment in Randomized Complete Block Design (RCBD) with three replicates. The results showed that: High rate of 2,4-D (24×103 mg) gave a high concentration of proline, which gave 115,59 and 108,10 mg/g.: 142.25 and 145.60 mg/g in the two winter, and two rainy seasons, respectively. In both winter seasons leaves proline increased as the 2,4-D concentration increased dissolved in diesel with the three sizes, while in both rainy seasons, all 2,4-D concentrations dissolved in water or diesel increased proline content compared to the control. The results in this research confirmed that: 2,4-D herbicide led to a significant increase in leaves proline content of mesquite trees to a degree that lead to toxicity of the tree, which is one of the mechanisms of action of auxin overdose.