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|Title:||An Investigation Into the Synergistic Interaction of Tridiphane and Atrazine (Cyanazine, Giant Foxtail, Glutathione-S-Transferase)|
|Author(s):||Boydston, Rick Allen|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The primary purpose of this research was to investigate the herbicidal properties of tridiphane 2-(3,5-dichlorophyenyl)-2,2,2-trichloroethyl)oxirane in plants which contribute to the synergistic effect often observed when tridiphane is applied with atrazine 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine .
The effect of tridiphane on atrazine metabolism and uptake was examined by in vitro and in vivo studies. Tridiphane inhibited isolated glutathione-s-transferase (GST) activity from corn and giant foxtail with an I(,50) of about 5 (mu)M. The specific activity of GST isolated from corn seedlings was 14 fold higher than the specific activity of GST isolated from giant foxtail seedlings. GST activity and reduced glutathione (GSH) levels were greater in leaf tissue than in stem tissue, and the amount of GSH/g fresh wt was greater in four-leaf giant foxtail seedlings (2.4 (mu)moles/g fresh wt) than in two-leaf seedlings (1.3 (mu)moles/g fresh wt).
Tridiphane partially inhibited the metabolism of atrazine to water soluble metabolites in giant foxtail leaves but not in corn leaves resulting in the greatest amount of unmetabolized atrazine in giant foxtail seedlings (83 nmoles/g fresh wt). Tridiphane applied 12 hours prior to atrazine increased the uptake of atrazine in corn leaves and in five-leaf giant foxtail seedlings. Applying tridiphane with atrazine increased atrazine uptake in corn but not in giant foxtail seedlings.
Tridiphane and atrazine combinations impaired photosynthesis more than atrazine alone in giant foxtail leaves, indicating greater levels of unmetabolized atrazine. Tridiphane alone did not lower photosynthetic rates in corn or giant foxtail leaves.
Tridiphane also inhibited the growth of corn cells growing in liquid media with an I(,50) of approximately 5 (mu)M. Tridiphane was rapidly metabolized by corn cells to a compound which was more polar than tridiphane.
Field studies indicated that tridiphane applied with atrazine improved the control of giant foxtail over that of atrazine alone, and allowed for the use of lower atrazine rates. The improvement was greatest when applied to giant foxtail in the 3- to 5-leaf stage of giant foxtail. The maximum synergistic effect between tridiphane and atrazine occurred when atrazine was applied 24 hours after tridiphane application.
Larger giant foxtail seedlings (over 8 cm tall) were more difficult to control with single applications of tridiphane plus atrazine and two successive applications eight days apart resulted greater control.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.
|Date Available in IDEALS:||2014-12-16|