The Mode of Action of Foliage‐applied Translocated Herbicides With Particular Reference to the Phenoxy‐acid Compounds

Robertson, Margaret M.; Kirkwood, R. C.

doi:10.1111/j.1365-3180.1969.tb01478.x

Cited by 56 publications

(50 citation statements)

References 221 publications

(149 reference statements)

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“…Increased temperatures altered the uptake and translocation of simazine [2-chloro-4,6bis(ethylamino)-s-triazine] and terbutryn (2-tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine] by promoting high transpiration (Dudek et al 1973, Sheets 1961. High levels of relative humidity influenced dalapon uptake into plants by hydrating the cuticle (Clor et al 1962), while light variations influenced dalapon movement by altering photosynthate translocation (Burton et al 1959, Foy 1962, Robertson and Kirkwood 1970.…”

Section: Introductionmentioning

confidence: 99%

Factors Affecting Dalapon Absorption and Translocation in Johnsongrass

McWhorter

Jordan

1976

Physiologia Plantarum

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The factors affecting the absorption and translocation of 14C‐dalapon (2.2‐dichloropropionic acid) in johnsongrass were studied. Johnsongrass [Sorghum halepense (L.) Pers.] was first pot‐grown in a greenhouse and then treated and placed in controlled‐environment chambers. Absorption of 14C‐dalapon into johnsongrass leaves and subsequent translocation occurred continuously within the plant during a 48‐h period after treatment. Gas chromatographic analysis of johnsongrass extracts showed that the dalapon molecule was translocated intact. Absorption and translocation of 14C‐dalapon increased as the droplet volume of the diluent was increased from 0.2 to 5.0 μl per treated spot. At 21 and 32°C, translocation of 14C‐dalapon from a 2‐cm treated leaf section into the plant was greater at 100% than at 35% relative humidity. At 38°C, translocation was greater at 35% than at 100% relative humidity. The addition of 0.5% surfactant to the dalapon solution increased translocation under all environmental conditions studied. The addition of 0.1 M KH2PO4 to dalapon‐surfactant solutions increased 4‐dalapon translocation under high temperature (38°C), especially at 35% relative humidity.

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Section: Introductionmentioning

confidence: 99%

Factors Affecting Dalapon Absorption and Translocation in Johnsongrass

McWhorter

Jordan

1976

Physiologia Plantarum

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“…Slow penetration of the herbicides into the wheat leaves may be one such factor, although not decisive. Uptake may be changed drastically by environmental conditions and spray additives (Robertson and Kirkwood 1969) while resistance in grass species is largely unaffected by these factors. In the present experiments all the applied herbicide was eventually absorbed due to use of conditions favoring uptake.…”

Section: Discussionmentioning

confidence: 99%

“…Such mechanisms involve rapid breakdown of the herbicide molecule most often recorded as a decarboxylation (Weintraub et al 1952, Luckwill andLloyd-Jones 1960) or inactivation of the compound by its adsorption to sites not concerned in the physiological response (Brian 1958), by incorporating it in complexes with proteins largely located in the cell wall fraction Rakitin 1968, Zemskaya et al 1971) or in water-soluble conjugates (Andreae andGood 1957, Fang 1958). The metabolism of herbicides in plant tissues has been reviewed by Swanson (1965) and Robertson and Kirkwood (1970). Estrusion of the herbicide through the roots is another possible protective mechanism reported for several species (Clor 1961, Reid andHurtt 1970) and suggested to be a factor in selectivity by Fites et al (1964).…”

Section: Introdiictionmentioning

confidence: 99%

Translocation and Complex Formation of Picloram and 2,4‐D in Wheat Seedlings

Hallmén

Eliasson

1972

Physiologia Plantarum

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Uptake, translocation and metabolism of 14C‐labelled 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) in seedlings of wheat (Triticum aestivum L.) were studied. The uptake of the herbicides through the upper surface of the first leaf was slow but was almost complete after nine days. Picloram was absorbed faster than 2,4‐D. Picloram was also translocated into the stem and the untreated leaves to a greater extent than 2,4‐D. Only small fractions of the activity were recovered from the roots and from the nutrient solution. Picloram and 2,4‐D formed water‐soluble conjugates in the tissues. These conjugates were very labile and hydrolyzed under release of the unchanged herbicides. The isotope from 2,4‐D was also incorporated in an insoluble fraction, containing cell walls and proteins. Also from this fraction biologically active 2,4‐D could be released by hydrolysis. The formation of the complexes was partly prevented by cycloheximide. It is suggested that herbicide detoxification through complex formation is of importance for the relatively low sensitivity of wheat to auxin herbicides.

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“…Usual rates of assimilate movement in the phloem have been reported to be roughly 50-100 cm h-l [49], whereas rates of water flow in xylem vessels may vary from 0 to 100 m h-1 [22]. Studies by Price [42,50] have shown that the normal rate of xylem transport of the non-pesticidal l-methylpyridinium chloride (MPC) is almost twice that in the phloem.…”

Section: Translocationmentioning

confidence: 99%

“…Under conditions of low relative humidity, surfactants are usually more effective in promoting uptake than under conditions of high humidity. This probably relates to the fact that they are hygroscopic in nature and at low humidity act secondarily as humectants, thereby prolonging the time a spray droplet remains on the leaf and extending the absorption period [22].…”

Section: Uptake and Transport Foliar Uptakementioning

confidence: 99%