Behavior and Fate of Metribuzin in Soybean and Hemp Sesbania

Abstract

The absorption, translocation, and metabolism of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H) one] by soybean (Glycine maxMerr. ‘Lee 68′) and hemp sesbania (Sesbania exaltataL.) grown in nutrient solution and in soil treated with14C-metribuzin were investigated. Absorption studies indicated there were no significant differences in the amount of14C-metribuzin absorbed from treated nutrient solution by soybean (tolerant) and hemp sesbania (susceptible). When these species were grown in14C-metribuzin treated soil, hemp sesbania absorbed appreciably more herbicide than did soybean.14C-metribuzin and (or) its14C-metabolites were translocated from the roots to the shoots of both species. Radioactivity was rapidly translocated and accumulated in all the leaves of hemp sesbania, but it tended to accumulate to the greatest extent in the roots and lower leaves of soybean. Translocation differences between the two species were apparent in plants grown either in soil or nutrient solution treated with14C-metribuzin. However, differences were greatest in plants grown in treated soil. Preliminary metabolic studies indicated that a higher rate of metribuzin degradation occurred in soybean than in hemp sesbania. The major14C-metabolite appeared to be the relatively nonphytotoxic deaminated diketo derivative [6-tert-butyl-1,2,4,-triazine-3-5(2H,4H)dione]. Thus, differences in the absorption, translocation, and metabolism of metribuzin all appeared to contribute to the differential susceptibility of soybean and hemp sesbania to metribuzin.

Mechanistic basis for synergism of 2,4-D amine and metribuzin in <i>Avena sterilis</i>

“…Metribuzin is a selective herbicide in certain crops due to the different rates of metabolism between crop and weed. [35][36][37] The metribuzin metabolism has been demonstrated in these crops via nonconjugative and conjugative metabolic pathways. For the nonconjugative pathway, metribuzin is metabolized via deami-nation and dethiomethylation to deaminated metribuzin (DA), diketo metribuzin (DK), and deaminated diketo metribuzin (DADK).…”

“…For the nonconjugative pathway, metribuzin is metabolized via deami-nation and dethiomethylation to deaminated metribuzin (DA), diketo metribuzin (DK), and deaminated diketo metribuzin (DADK). [35][36][37] The N-glucoside and homoglutathione conjugations of metribuzin were reported to be the major detoxification pathway in tomato and soybean, respectively. [38][39][40] Our experiments demonstrated that metribuzin can be metabolized to some extent in susceptible A. sterilis, and 2,4-D amine pretreatment clearly enhanced metribuzin metabolism (Table 3, Fig.…”

Metribuzin resistance via enhanced metabolism in a multiple herbicide resistant Lolium rigidum population

“…Metribuzin metabolism is known in naturally tolerant crops (e.g. soybean, wheat) 14,15 and field‐evolved metribuzin resistant weeds (e.g. Raphanus raphanistrum L.) 16 .…”

Influence of Date and Method of Metribuzin Application for Quackgrass Control in Alfalfa1

“…Metribuzin activity following field application is mediated by factors such as soil pH and organic matter content ( 12), application rate and date (3,5). Both metribuzin (6) and the striazine herbicides (15) are readily translocated acropetally by both sensitive and tolerant plants. Alfalfa tolerance is partly due to its deep taproot system (5).…”