Uptake, Translocation, and Metabolism of MG-191 Safener in Corn (Zea Mays L.)

Abstract

The time-dependent uptake, translocation, and metabolism of [14C]MG-191 safener and the influence of EPTC on these processes were studied using 5-d-old corn seedlings grown in nutrient solution. Plants absorbed relatively low levels of root-applied radiolabel at both 10 μM and 50 μM [14C]MG-191 rates during 6 d of exposure. Amounts of absorbed radioactivity increased with time. Addition of 50 μM EPTC, in general, did not alter amounts of [14C]MG-191 taken up. Initial translocation of radiolabel from roots to shoots was more rapid at 10 μM [14C]MG-191 treatment compared to 50 μM. EPTC had no effect on radiolabel movement at either safener rate. MG-191 was metabolized rapidly to water-soluble metabolites. Slower formation of water-soluble products was detected only during the initial 3 h in the presence of EPTC. Also, thin-layer chromatographic analyses of water- and hexane-soluble metabolite fractions confirmed rapid transformation of the parent molecule. Because addition of EPTC retarded parent MG-191 metabolism 3 h after treatment, we assume that initial availability of the MG-191 molecule may be prerequisite to its protective effect.

Herbicide Safeners: Effective Tools to Improve Herbicide Selectivity

“…Studies on how maize can differentiate in the absorbtion of herbicides and safeners were conducted with radiolabeled EPTC, acetochlor and MG-191 [42,43]. Time-dependent uptake of root-applied [ 14 C]EPTC reached a maximum after 6h and decreased up to 3 days ( Figure 1).…”

Herbicide safeners: a review

“…In fact, with the exception of Riden and Asbell, 164 Jablonkai and Dutka 165 and Yenne et al 60 who investigated the fate of NA, MG 191 and the oxime ether safeners oxabetrinil and¯uxofenim, respectively, few publications have contemplated the issues of safener uptake, translocation and metabolism. These investigations are becoming essential now that safeners are subject to the same environmental risk assessment procedures as herbicides themselves.…”

Synthesis and Crystal Structure of 2‐(Dichloromethyl)‐2‐(4‐nitrophenyl)‐1,3‐dioxane

“…The 2-dichloromethyl-1,3-dioxacycloalkane compounds have received considerable attention due to safening activities against herbicidal injuries to crop plants [1]. 2-Dichloromethyl-1,3-dioxacycloalkane derivatives, such as MG-191 [2], have been investigated as herbicide safeners which protected crops from the injury by herbicides [3,4]. Various substituents of the dioxacycloalkane have showed different activities, which encouraged us to synthesize novel 2dichloromethyl-1,3-dioxane derivatives with enhanced biological activity.…”