Uptake of Herbicides by Soybean Seed

Abstract

The uptake of herbicides by soybean (Glycine max(L.) Merr.) seed from14C-labeled aqueous solutions of 3-amino-2,5-dichlorobenzoic acid (amiben), 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron),S-ethyl dipropylthiocarbamate (EPTC), and isopropylm-chlorocarbanilate (chlorpropham) was determined by measuring reduction in the concentration of the herbicides in the soaking solution. There was a direct proportional relationship between uptake and concentration. Raising the temperature from 10 to 30 C increased uptake of herbicides. The greatest increase occurred from 10 to 20 C. After 48 hr at 30 C, 39% of the amiben, 61% of the atrazine, 65% of the EPTC, 83% of the linuron, and 92% of the chlorpropham in the original solution was absorbed by the seed. Uptake rates were similar in living and dead seed. Uptake was reversible with amiben but not with chlorpropham. Absorption of herbicides could not be associated with absorption of water except during the first few hours when the seed were rapidly imbibing water. Ratios of seed to solution herbicide concentrations all exceeded 1:1 after 48 hr and with chlorpropham, reached 68:1. The uptake of herbicides by seed was largely a physical process that required seed hydration, but herbicide uptake continued after water uptake ceased.

Uptake of Triticonazole, during Imbibition, by Wheat Caryopses after Seed Treatment

“…The uptake of triticonazole by wheat seeds from an aqueous solution had a di †erent pattern to that previously described for di †erent herbicides and soybean seeds.6h9 For linuron Rieder et al 6 found in soybean seeds a 28 : 1 accumulation ratio from a 20 mg litre~1 herbicide solution, whereas for triticonazole the accumulation ratio reached only 2 : 1 after 24 h imbibition. The accumulation of linuron resulted from trapping processes, presumably into soybean seed lipids since linuron is lipophilic : its log (octanol-water partition K ow coefficient) is 3É0 and its water solubility is 81 mg litre~1.21 Triticonazole is also lipophilic (log K ow \ 3É3, water solubility \ 7 mg litre~1)22 but the lipid content of wheat seeds is low (2È3% versus 15È25% for soybean seeds8).…”

“…The mechanisms of pre-emergence herbicide uptake in soybean seed were studied by soaking seeds in aqueous solutions of herbicides.6h9 The absorption pattern was found to depend on the physicochemical properties of the active ingredient. Lipophilic compounds are taken up in soybean seed via di †usion, 6,8,9 and are accumulated in seed tissues by trapping processes, probably into lipids. 10,11 More polar compounds are less accumulated, 6,8,9 and their uptake may depend more on mass Ñow.9 * To whom correspondence should be addressed.…”

Systemic Seed Treatment Uptake during Imbibition by Corn and Soybean

“…As a class of compounds, coumarins have been used as fluorescent probes in many systems 'IAR 1902', 'TMG 132RR', and'V12-1223' and their fitting curves with model Y = y 0 − Ae −kx , where y 0 is the uptake limit, A and k are constants, and x is the applied dose rate. For example, the uptake of herbicides (linuron, chlorpropham, atrazine, EPTC, and amiben) by soybean seeds was directly proportional to concentration of soaking solution in the range of 0.02 to 0.32 mM (Rieder et al, 1970). The concentration curves of absorbed coumarin 120 for corn (Fig.…”

“…For example, systemic neonicotinoid seed treatment insecticides are used worldwide to control foliar pests (Douglas and Tooker, 2015). seeds was investigated over a 16-fold range (Rieder et al, 1970), and the fungicide triticonazole was tested over a 5.3-fold range (Quérou et al, 1998). There are few reports on the uptake of agrochemicals applied as seed treatments and generally under limited dosages that are used for pest management.…”

New and Scalable Access to Karrikin (KAR1) and Evaluation of Its Potential Application on Corn Germination

“…Despite seed uptake of exogenous chemicals is critical, limited studies attempted to understand what mechanisms are involved in the processes . Early reports disclosed simple and sufficiently precise methods to study the seed uptake of herbicides in different species . A similar methodology was used in this study to evaluate the seed uptake of KAR 1 .…”