Effect of ammonium sulfate on the phytotoxicity, foliar uptake, and translocation of imazamethabenz in wild oat

Abstract

Abstract. Experiments were conducted in greenhouse, growth chamber, and laboratory conditions to determine the effect of ammonium sulfate [(NH4)2504] on the phytotoxicity, foliar uptake, and translocation of imazamethabenz on wild oat. Rates of (NH4)2SO 4 up to 5% (w/v) applied with a greenhouse sprayer did not affect the phytotoxicity of the herbicide when the mix was applied at the one-to two-leaf stage. However, inclusion of 1 and 2% (NH4)2SO 4 increased the phytotoxicity of the herbicide when the mix was sprayed at the two-to three-leaf, or the three-to four-leaf stage. At 10%, (NH4)2SO 4 decreased the phytotoxicity of the sublethal dosage of the herbicide. When the herbicide was applied as individual drops to the growth chamber-grown plants, inclusion of (NH4)2SO 4 at 1% did not affect phytotoxicity as measured by shoot growth. The presence of (NH4)2SO 4 did not affect the amount of imazamethabenz retained by wild oat foliage, but it decreased [14C]imazamethabenz absorption, slightly antagonized acropetal translocation, and increased the basipetal translocation of [14C]imazamethabenz. It was concluded that application methods greatly modify the effect of (NH4)2SO 4 on imazamethabenz phytotoxicity. Herbicide absorption and translocation as determined by one method do not necessarily represent the absorption and translocation patterns when different application methods are used. Absorption and translocation were not the factors that were responsible for the observed effect of (NH4)2SO 4 on the herbicide phytotoxicity.

Increased foliar activity of clodinafop‐propargyl and/or tribenuron‐methyl by surfactants and their synergistic action on wild oat (Avena ludoviciana) and wild mustard (Sinapis arvensis)

“…Previous studies have shown that the dose–response curves of a herbicide applied with and without surfactant is considered to be parallel (Kudsk et al . 1987; Hsiao et al . 1996; Devilliers et al.…”

Statistical Tests for Hormesis and Effective Dosages in Herbicide Dose Response

“…Several studies of dose–response trends following herbicide applications have used the log–logistic function to model dose–response relationships (e.g., Streibig, 1980, 1981; Lærke and Streibig, 1995; Seefeldt et al, 1995; Hsiao et al, 1996; Sandral et al, 1997). The log–logistic model expresses mean dose response as a sigmoidal, monotonic increasing or decreasing function in log(dose) that is symmetric about its point of inflection (Fig.…”

Método alternativo de avaliação da absorção de atrazine por plantas de Brachiaria plantaginea

“…A absorção foliar é comumente medida pela aplicação de gotículas de herbicidas radiomarcados nas folhas, medindo-se a radiação remanescente na superfície foliar em vários intervalos de tempo após a aplicação por meio da lavagem da folha (Al Khatib et al, 1992;Gaskin & Holloway, 1992;Green et al, 1992;Roggenbuck et al, 1994;Hsiao et al, 1996;Wahlers et al, 1997;Sprague et al, 1999). Um cuidado importante nessa técnica envolve a escolha do solvente para lavagem da superfície foliar.…”