Studies on Foliar Penetration: I. FACTORS CONTROLLING THE ENTRY OF 2, 4 - DICHLOROPHENOXYACETIC ACID

Sargent, John; Blackman, G. E.

doi:10.1093/jxb/13.3.348

Cited by 93 publications

(80 citation statements)

References 23 publications

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“…Apricot leaf disks were prepared for the uptake studies using the technique of Sargent and Blackman (1962) as modified by Greene and Bukovac (1971). Glass cylinders (height 10 mm; external diameter 24 mm; internal diameter 21 mm) were attached to the upper, astomatous surface of leaf disks (diameter 25 mm) using RTV Illiquid silicone rubber (General Electric Company, Waterford, New York) hardened with Harter T I catalyst (Wacher Chemie GMBH Company, Munich, Germany)_ The disks were placed in 9-cm Petri dishes lined with moist filter paper, and 1·0 ml ofO'4M KCl (control) or 0·4M KNOa (enzyme induction solution) was pipetted into each cylinder.…”

Section: Methodsmentioning

confidence: 99%

Influence of Epicuticular Waxes on Foliar Absorption of Nitrate Ions by Apricot Leaf Disks

Leece¹,

Kenworthy²

1972

Aust. Jnl. Of Bio. Sci.

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The poor response of Prunus spp. to foliar nitrate sprays under field conditions (Leece and Kenworthy 1971) is not caused by an inability of Prunusleaves to metabolize nitrate ions (Leece, Dilley, and Kenworthy 1972). This is analogous to the response ofPrunus spp. to urea sprays (Dilley and Walker 1961a). Dilley and Walker (1961b) demonstrated that pretreatment of peach leaf disks by immersion in acetone to dissolve lipid components of the cuticle increased subsequent urea absorption. Bukovac (1965) found that lightly brushing the upper and lower surfaces of peach leaves with a camel-hair brush enhanced uptake of 3-chlorophenoxy-a-propionic acid by 22 and 34% respectively. Brushing was assumed to have partially removed or rearranged the epicuticular waxes.This paper reports that the uptake of nitrate ions by apricot leaf disks, via the astomatous cuticle, was enhanced by partial removal or disruption of the epicuticular waxes. Materials and MethodsFully expanded, mid-shoot leaves were obtained from 5-year-old apricot trees (Prunus armeniaca L. cv. Curtis) growing at East Lansing during the summer of 1970. The leaves were transferred to the laboratory in polyethylene bags at 0-4°C.Nitrate ion uptake by apricot leaves was assayed by measuring the induction of nitrate reductase in excised leaf disks, following cuticular penetration. Apricot leaf disks were prepared for the uptake studies using the technique of Sargent and Blackman (1962) as modified by Greene and Bukovac (1971). Glass cylinders (height 10 mm; external diameter 24 mm; internal diameter 21 mm) were attached to the upper, astomatous surface of leaf disks (diameter 25 mm) using RTV Illiquid silicone rubber (General Electric Company, Waterford, New York) hardened with Harter T I catalyst (Wacher Chemie GMBH Company, Munich, Germany)_ The disks were placed in 9-cm Petri dishes lined with moist filter paper, and 1·0 ml ofO'4M KCl (control) or 0·4M KNOa (enzyme induction solution) was pipetted into each cylinder. Both solutions contained 0·1 % (v/v) X 77 surfactant (alkylarylpolyoxyethylene glycols, free fatty acids, and isopropanolChevron Chemical Company, Ortho Division, San Francisco, California). The dishes were incubated in a water-bath at 25°C for 15 hr and at a light intensity (from fluorescent tubes) of 8600 lux at leaf level. Following incubation, the glass cylinders were peeled off the disks, the disks were rinsed with distilled water, blotted dry, then assayed for nitrate reductase as previously reported (Leece, Dilley, and Kenworthy 1972).Where required, disruption and partial removal of epicuticular waxes was achieved either by brushing (10 strokes in one direction with a camel-hair brush), or with 80% (v/v) aqueous acetone (leaf wiped with acetone-treated tissue paper then dried immediately with untreated paper). Chloroform proved unsuitable for wax removal as it produced leaf senescence within 3 hr.

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Section: Methodsmentioning

confidence: 99%

Influence of Epicuticular Waxes on Foliar Absorption of Nitrate Ions by Apricot Leaf Disks

Leece¹,

Kenworthy²

1972

Aust. Jnl. Of Bio. Sci.

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“…O aumento do controle da trapoeraba sob sombra pode estar relacionado com as alterações morfofisiológicas ocorridas em suas estruturas celulares, levando a planta a investir mais recursos para aumentar a sua área fotossintética, em relação à sua proteção. Entre essas modificações atribuídas ao estresse luminoso estão a menor deposição de ceras epicuticulares hidrofóbicas na epiderme, o aumento da lâmina foliar e das estruturas secretoras presentes nesta e da permeabilidade das células na base dos tricomas, garantindo maior tempo de exposição da calda química e redução das barreiras à penetração desta (Sargent & Blackman, 1962;Santos et al, 2002;Monquero et al, 2004a;Gobbi et al, 2009 Média das quatro repetições, aos 10 DAA e aos 20 DAA. 0 a 10%, * a 5% e ** a 1% de significância.…”

Section: Resultados E Discussão Manejo De Trapoeraba (Commelina Benghunclassified

Manejo de tiririca e trapoeraba com glyphosate em ambientes sombreados

Júnior¹,

Santos²,

Costa³

et al. 2013

Planta daninha

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RESUMO -Plantas daninhas mantidas em ambientes com redução da intensidade luminosa apresentam alterações morfofisiológicas marcantes, que podem alterar seu comportamento reprodutivo e a tolerância a herbicidas aplicados em pós-emergência. Objetivou-se neste estudo avaliar a eficiência de doses de glyphosate no manejo da trapoeraba (Commelina benghalensis) e da tiririca (Cyperus rotundus) cultivadas em diferentes níveis de sombreamento. O trabalho foi composto por dois ensaios, referentes a cada uma das espécies, com o mesmo delineamento experimental, sendo constituídos em esquema fatorial 5 x 3, com cinco doses de herbicida (0, 540, 810, 1.080 ou 1.350 g ha -1 de glyphosate), três ambientes de cultivo (0, 30 ou 50% de sombra) e quatro repetições. As parcelas experimentais foram compostas por um vaso com duas plantas de tiririca ou de trapoeraba. As avaliações de controle ocorreram aos 10, 20 e 30 dias após a aplicação (DAA), por meio de observações visuais. Aos 30 DAA, foi determinada a massa seca da parte aérea de cada espécie. A produtividade de tubérculos foi observada pela contagem direta desses propágulos presentes nas raízes das plantas de tiririca. Já a sua viabilidade foi avaliada por teste de germinação em leito de areia e por tetrazólio no caso dos não germinados. O controle das espécies foi mais eficiente em ambientes sombreados, contribuindo para a redução de até 25% da dose recomendada para ambas, obtendo-se controle de 81% para trapoeraba e 100% para tiririca. Já a matéria seca da parte aérea, a produtividade e a viabilidade dos tubérculos foram afetadas pelo aumento do nível de sombra e pela dose de glyphosate. A diminuição da intensidade luminosa -comum no sub-bosque de culturas arbóreas e arbustivas ou quando do adensamento de cultivosrepresenta prática interessante na supressão da trapoeraba e da tiririca e potencializa a ação de controle do glyphosate.Palavras-chave: ecofisiologia, controle químico, tolerância, sombra.ABSTRACT -Weeds maintained in reduced light intensity environments present remarkable morphophysiological changes that may alter their reproductive behavior and tolerance to post-emergence herbicides. Our goal was to evaluate the efficiency of glyphosate doses in the management of Commelina benghalensis and Cyperus rotundus grown at different levels of shading. The work consisted of two trials for each species with the same experimental design, in a 5 x 3 factorial design with five herbicide doses (0, 540, 810, 1.080, and 1.350 g ha -1 of glyphosate), three cultivation environments (0, 30, or 50% of shading) and four replicates. Experimental plots consisted of a vase with two plants of either C. benghalensis or C. rotundus. Control evaluations were carried out 10, 20, and 30 days after application (DAA) through visual observations. Tuber productivity was verified by direct counting of these propagules present in the roots of C. rotundus plants, while tuber viability was evaluated by germination test in a sand bed, and by tetrazolium, for the nongerminated tubers. Species control ...

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“…The cuticle is generally considered to be the principal site of entry, although under certain conditions the stomatal apparatus may play a significant role (Crafts and Foy, 1962;Sargent and Blackman, 1962;Franke, 1964;Currier, Pickering and Foy, 1964). Stomatal movement is known to be affected by chemical stimuli, such as abscisic acid (Jones and Mansfield, 1970), kinetin (Meidner, 1967) and farnesol (Ogunkanmi, Wellburn and Mansfield, 1974); and more recently the work of Pemadasa and Jeyaseelan (1976) suggests that herbicides may also influence stomatal movements in susceptible plants.…”

Section: Introductionmentioning

confidence: 99%