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Title:Studies on the Herbicidal Properties of Sn 533 (Epronaz) (1- (n-Ethyl- N-Propylcarbamoyl) -3-Propyl-Sulphonoyl) -1,2,4-Triazole) and Its Uptake, Translocation and Metabolism by Soybeans and Peanuts
Author(s):Harrison, Howard Franklin, Jr.
Department / Program:Agronomy
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Agronomy
Abstract:The purpose of this study was to evaluate SN 533 for preemergence and postemergence herbicidal activity, and to determine its fate in soybeans (Glycine max L.) and peanuts (Arachis hypogea L.).
Field studies indicated that preemergence and postemergence application of SN 533 gave inadequate levels of weed control. The lack of preemergence activity was attributed to the droughty conditions occurring after herbicide application in all experiments.
Root applied SN 533 proved to be highly phototoxic to plants growing in nutrient solution culture. Peanut was most resistant of the species tested. Soybean exhibited moderate susceptibility to SN 533 and large crabgrass {Digitaria sanguinalis (L.) Scopoli} and barnyardgrass {Echinochloa crusgalli (L.) Beauv.} were highly susceptible. Inhibition of meristematic activity was the most noticeable symptom of SN 533 injury.
Approximately 13% of ('14)C-label from foliar applied ('14)C-SN 533 was translocated out of the treated leaf of soybeans, and about 2% of the ('14)C-label was translocated out of the treated leaf of peanuts. Meristem accumulation of ('14)C-label was much higher in soybeans than in peanuts after 1 day, but the specific activity of soybean meristems declined after 4 and 8 days.
Root applied ('14)C-SN 533 was readily absorbed by both species; however, translocation of the ('14)C-label into the shoot occurred more rapidly in soybeans than in peanuts. Total absorption of ('14)C-label per gram dry weight was higher in peanut plants than in soybean plants after 8 days.
Root absorbed ('14)C-SN 533 was rapidly metabolized by soybeans and peanuts. After 8 days, less than 2% of the total extractable radioactivity was identified as unaltered SN 533 by thin layer chromatography. The level of unaltered SN 533 after 1 day was higher in soybeans than in peanuts. The disappearance of ('14)C-SN 533 coincided with the appearance of unknown polar metabolites in both species.
After 12 hours, less than 5% of petiole absorbed ('14)C-label in leaflets of pulse treated, excised soybean leaves was characterized as extractable, unaltered SN 533. No extractable, unaltered SN 533 was detected in peanut leaflets after 12 hours. The rate of SN 533 metabolism appeared to be somewhat more rapid in peanut leaflets than in soybean leaflets; however, the concentration of ('14)C-label was higher in soybean leaflets than in peanut leaflets.
The major components of the unknown polar ('14)C-metabolites extracted from soybean and peanut leaflets appeared to be different. The release of PST (3-propylsulphonyl-1,2,4-triazole) by alkaline hydrolysis of the unknowns suggested that they were bound or conjugated forms of SN 533 or PST.
Residues of ('14)C-SN 533 were present in all analyzed sections of soybean and peanut plants that were planted in treated soil and harvested at flowering and at maturity. Generally, ('14)C-label concentrations and total ('14)C absorption was higher in soybeans than peanuts. Most of the extractable ('14)C occurred as unidentified polar metabolites, but ('14)C-PST was found in all sections analyzed except peanut seeds.
The results of this study suggest that SN 533 is rapidly metabolized to polar conjugates in soybeans and peanuts. Differential translocation and metabolism of the herbicide by soybeans and peanuts may be involved in the observed differences in its phytotoxicity to the two species.
Issue Date:1980
Description:86 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
Other Identifier(s):(UMI)AAI8026513
Date Available in IDEALS:2014-12-14
Date Deposited:1980

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