Metabolism of Tordon Herbicide (4-Amino-3,5,6-trichloropicolinic Acid) in Cotton and Decomposition in Soil

Meikle, R. W.; Williams, Elizabeth A.; Redemann, Carl T.

doi:10.1021/jf60146a015

Cited by 33 publications

(19 citation statements)

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“…Esses resultados estão de acordo com os de MacDonald et al (1976), os quais detectaram presença de picloram no solo por período superior a um ano após a aplicação. Estimativas da persistência de concentrações potencialmente tóxicas deste herbicida mostram variação de alguns meses até três anos, dependendo do tipo de solo e das condições ambientais (Silva, 2005;Scrifres et al, 1971;Fryer et al, 1979;Johnsen Jr., 1980;Norris et al, 1986;Neary et al, 1985;Bovey & Richardson, 1991;Deubert & Corte-Real, 1986;WSSA, 1994).…”

Section: Resultsunclassified

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Eficácia e persistência no solo de herbicidas utilizados em pastagem

Santos

Freitas²,

Ferreira³

et al. 2006

Planta daninha

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Este trabalho teve como objetivo avaliar a eficácia dos herbicidas 2,4-D + picloram (Tordon), fluroxypyr + picloram (Plenum) e triclopyr (Garlon) no controle de aroeirinha (Schinus terebintifolius) e mata-pasto (Eupatorium maximilianii), bem como a ação residual desses herbicidas no solo. O estudo foi conduzido em pastagem estabelecida de capim-gordura (Melinis minutiflora). O delineamento experimental foi em blocos casualizados, com quatro repetições e 13 tratamentos, distribuídos em esquema fatorial (3x4+1), sendo duas misturas comerciais e um herbicida, aplicados em quatro doses: 2,4-D + picloram [360 + 96 g ha-1; 720 + 192 g ha-1; 1.080 + 288 g ha-1; 1.440 + 384 g ha-1]; fluroxypyr + picloram [120 + 120 g ha-1; 240 + 240 g ha-1; 380 + 380 g ha-1; 480 + 480 g ha-1] e o herbicida triclopyr (240, 480, 720 e 960 g ha¹), além de uma testemunha sem herbicida. Foram realizadas avaliações de intoxicação na pastagem aos 7 e 15 DAA e de controle das plantas daninhas aos 60 e 180 DAA. O resíduo no solo foi avaliado por meio de bioensaios em vasos, em casa de vegetação, com amostras de solo coletadas nas parcelas experimentais, nas profundidades de 0 a 10 e 10 a 20 cm, aos 10, 40, 70, 120, 180 e 360 DAA, utilizando-se pepino (Cucumis sativus) como planta indicadora. Controle superior a 90% de Schinus terebintifolius e Eupatorium maximilianii foi obtido aos 180 DAA, respectivamente a partir de: 2,78 e 2,46 L ha-1 para o Tordon; 1,97 e 2,02 L ha-1 para o Plenum; e 1,23 e 1,44 L ha-1 para o Garlon. Verificou-se resíduo no solo até os 360 DAA para as misturas comerciais de herbicidas que continham picloram na formulação. Resíduo do herbicida triclopyr foi observado somente nas amostras coletadas aos 10 DAA, indicando curta persistência no solo.

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Section: Resultsunclassified

“…Quando aplicada à folhagem, a maioria do picloram (70-90%) permanece nas folhas, e apenas uma porcentagem pequena é conduzida para caules e raízes (Meikle et al, 1966;Cessna et al, 1986;Hickman et al, 1990).…”

Section: Resultsunclassified

Eficácia e persistência no solo de herbicidas utilizados em pastagem

Santos

Freitas²,

Ferreira³

et al. 2006

Planta daninha

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“…On the basis of work with cotton by Meikle et al (14), and the short time periods employed in these studies, the breakdown of the picloram molecule in the plant was presumed to be negligible. Curvature responses of stem and foliage were recordedl throughout the treatment periods.…”

Section: Methodsmentioning

confidence: 99%

“…sealing anid heatinlg at 750 for 90 nim. After cooling to room temperature, 14.5 ml of toluene-cellosolve scintillation solutioni (2 parts toluene, 1 part 2-ethoxyethanol (v/v ) alnd 6 g 2,5-diphenyloxazole/liter) Nvere added to eachl v-ial. Background determinations were obtained from unitreated plant sanmples.…”

Section: Methodsmentioning

confidence: 99%

Translocation and Distribution of Picloram in Bean Plants Associated with Nastic Movements

Reid¹,

Hurtt²

1969

Plant Physiol.

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Abstract. Nastic responses in bean plants (Phaseolus vulgaris L. var. Black Valentine) occur rapidly when very low ooncentrations of picloram (4-amino-3,5,6-trichloropicolinic acid) are applied to the root systems. The distribution of pioloram associated with nastic responses was quantitatively determined in root-treated plants.Sixty-seven micrograms of 14C-labeled picloram and 72 sg of unlabeled picloram in 300 ml of nutrient solution were applied to roots of 9-day old bean plants growing in an environmental growth chamber at 240 and 56 % relative humidity. Plants were removed from the treatment solution after uptake periods of 3, 6, and 11 hr. Sections were excised from 10 locations on each plant and 14C content was determined by liquid scintillation techniques. As a qualitative indication of picloram mobility, additional plants were treated for 3 hr and subjected to autoradiographic analysis.The accumulation of picloram within various parts of the plant increased with treatment time. After 3 hr of picloram uptake, a curvature of 60 to 80°from vertical in the upper 50 to 60 mm of stem corresponded to an accumulation in that part of the plant of 0.300 (second internode sample) to 1.065 (terminal bud sample) ng of picloram per mg fresh weight. The appearance of hyponasty in the trifoliolate leaflets after 6 hr of treatment corresponded to a picloram concentration in the leaf of 0.803 to 0.855 ng per mg fresh weight.As evidenced by the 14C count data, the translocation of picloram from the roots to the apical part of the plant was very rapid. Picloram was preferentially accumulated in the terminal bud and first trifoliolate leaflets. Very little picloram was transported to the primary leaves and only at the longer treatment periods. Autoradiographs of plants treated for 3 hr showed a qualitatively similar distribution of ;4C in the plant.The herbicide picloram (4-amino-3,5,6-trichloropicolinic acid) has been characterized as comparable to 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxvacetic acid (2,4,5-T) in absorption anid translocation by plants and leachability from soils, but as more effective oni many broad-leaved plants (6). Distortions in growing tissue, growth promotion in stem sections, and other morphogenetic effects caused by picloram have also been reported (4, 5,6,12 Materials and MethodsBean plants (Phaseolus vulgaris L. var. Black Valentine) were germinated in sand, transferred to aerated half-strength Hoagland and Arnon's nutrient solution (7) and grown in a controlled environment growth chamber. Uniform plants in which the first trifoliolate leaf had just opened (9 days old) were selected for use. Experiments were conducted at 24 + 0.50°56 ± 4 % relative humidity and a 16-hr photoperiod of 1460 ft-c of illumination at plant top level provided by a mixture of fluorescent and incandescent lighting.Plants were treated by immersing the root systems in foil-covered pint jars containing 300 ml of 1 ptNi picloram in half-strength nutrient solution. PLANT PHYSIOLOGY were obtaine...

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“…The phenoxyacetic acid herbicides are less persistent than other pesticides In soil and water ( 1, 2,8,15). The fate of picloram in soil and water has also been studied ( 3,4,13,11 ). However, there are very few studies on the degradation of these herbicides in rice soils.…”

Section: Please Scroll Down For Articlementioning

confidence: 99%