Absorption and Penetration of Picloram in Potato Tuber Discs

Swanson, Charles R.; Baur, J. R.

doi:10.1017/s0043174500054114

Cited by 12 publications

(12 citation statements)

References 7 publications

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“…Since picloram has strong auxin properties, it is reasonable to suggest that the uptake and accumulation of picloram by excised plant tissues proceeds by a mechanism similar to that proposed by Venis and Blackman (1966 b, c). Our results are in agreement with those of Baur and Bovey (1970) and Swanson and Baur (1969) who suggested a similar mechanism for uptake of picloram by potato tuber discs.…”

Section: Discussionsupporting

confidence: 93%

“…Very little work has been reported on the uptake of picioram by excised plant tissues. Baur and Bovey (1970) and Swanson and Baur (1969) suggested that the uptake of picioram by potato {Solanum tuberosutn L.) tuber discs occurs in part via an unstable accumulation mechanism similar to that proposed by Venis and Blackman (1966 b, c) for other auxin-herbicides. Although inhibitor studies are needed to characterize further the nature of picioram uptake, from the experiments of Swanson and Baur (1966) it appears that there is both a strong physical diffusion component and an associated metabolic component to uptake.…”

Section: Introductionmentioning

confidence: 71%

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Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues

Sharma

Born

1973

Physiologia Plantarum

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Excised soybean {Glycine max (L.) Merr.) hypocotyls, barley [Hordeum vulgare L.) coleoptiles, barley leaf sections,, and Canada thistle (Cirsium arvense (L.) Scop.) leaf discs continuously absorbed "C-picloram from a buffered solution over a 24 h period. After an 8 h uptake period excised sections released up to 30 Vo of the absorbed picioram into 'clean' buffer solution in a 4 h period. Leaf sections released less than did tke other tissues. Uptake of ^''C-picioram by soybean hypocotyl and barley coleoptiie sections increased with an increase in temperature from 5 to 35°C. Uptake was promoted by added ATP and sucrose but inhibited by actinomycin D, cycloheximide, and DNP.After differential centrifugation of aqueous extracts of '*Cpicloram-treated excised tissues more than 95 Vo of the radioactivity was in tke soluble fraction.Ira excised barley and Canada thistle leaf tissues, 3 days after treatment,, part of the '"C-picloram was conjugated with plant constituents,, largely with sugar(s). After acid hydrolysis of ethanol extracts of such tissues only unaltered picioram was detected. In barley coleoptile and soybean hypocotyl sections no conjugation products of ^''C-picloram were detected.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 71%

Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues

Sharma

Born

1973

Physiologia Plantarum

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“…However, absorption was similar when 14 Picloram absorption increased as spray solution pH decreased in detached live oak (Quercus virginiana Mill.) leaves and potato (Solanum tuberosa L.) disks (4,27). Greater root uptake of picloram at pH 3.5 than at pH 4.5 for oat (Avena sativa L.) and soybean [Glycine max (L.) Merr.]…”

Section: Introductionmentioning

confidence: 99%

Environment and Spray Additive Effects on Picloram Absorption and Translocation in Leafy Spurge (Euphorbia esula)

Moxness¹,

Lym²

1989

Weed sci.

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Relative humidity after application, spray additives, and solution pH affected both foliar absorption and translocation of14C-picloram to leafy spurge roots.14C-picloram absorption increased from 11 to 34% and translocation increased from 5 to 21% as time at posttreatment humidity increased from 0 to 48 h. Absorption and translocation were not different when pre- or posttreatment temperatures were 30/18 or 18/10 C (day/night).14C-picloram absorption and translocation to the roots were 18 and 6%, respectively, when applied alone, and increased to 46 and 12%, respectively, when applied with ammonium sulfate at 2.5 kg/ha. Absorption and translocation were unaffected by ammonium nitrate. Foliar absorption and translocation of14C-picloram in leafy spurge were unaffected by pH of unbuffered spray solution but increased at least 50% when applied in a solution buffered at pH 4.8 with trisodium citrate. Foliar absorption in detached leafy spurge leaves increased from 26 to 51% of applied14C as the citrate buffer concentration increased from 0.01 to 0.1 mM, respectively.

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“…Enhanced picloram uptake, which has been attributed to the influence of ATP on uptake mechanisms, actually may have been due to high H+-ion concentrations in inadequately buffered solutions. Numerous workers have demonstrated that picloram uptake is markedly enhanced at pH values less than the pK (4.1) of the acid (8,19). In preliminary experiments the addition of 5 m M ATP to unbuffered treatment solution reduced the pH to about 3.2, suggesting that enhanced uptake in the presence of ATP may be a direct result of lowered pH.…”

Section: Discussionmentioning

confidence: 95%

“…Many of the conclusions about the mechanisms involved in picloram absorption have been drawn from studies conducted with excised roots and various other plant tissues (2,14,16,17,19). Accordingly, a study was undertaken of the factors that affect absorption of picloram by intact roots of alfalfa (susceptible) and barley (resistant) plants.…”

Section: Introductionmentioning

confidence: 99%

Uptake of picloram by roots of alfalfa and barley

Morrison¹,

Born²

1975

Can. J. Bot.

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MORRISON, I. N., and W. H. VANDEN BORN. 1975. Uptake of picloram by roots of alfalfa and barley. Can. J. Bot. 53: 1774-1785. Uptake of [14C]picloram (4-amino-3,5,6-trichloropicolinic acid) from culture solution by alfalfa (Medicago scrti\.o L.) and barley (Hordeirm tzrrlgare L.) seedlings was investigated to determine to what extent passive and (or) active mechanisms are involved in the uptake of the herbicide by roots of intact plants. The roots of both species had similar absorption patterns consisting of rapid initial uptake lasting 1 to 2 h, followed by continuing absorption at a markedly lower rate during the rest of a 12-h treatment period. Initial uptake both by roots and whole plants was not significantly reduced by 1.0 mM NaN,, whereas continuing absorption was depressed by this inhibitor. Q,, values were 1.4foralfalfaand 1 .O for barley forthe first 1-2 hof uptake, whereas for subsequent periods the values were consistently greater than 2.0. Evidently. uptake during the initial phaseof entry is governed by passive processes, while continuing absorption iscontrolled, at least in part. by active mechanisms. Much of the picloram taken up by alfalfa and barley roots during a4-h treatment period was released rapidly tounlabelled nutrient solution. Uptake by both species was decreased in the dark and enhanced in the presence of sucrose. The results of inhibitor studies suggest that picloram absorption by alfalfa plants is more dependent on a supply of metabolic energy than is uptake by barley plants. In most instances, total accumulation of piclolam in 4 h was much greater in alfalfa plants than in barley plants of nearly equivalent mass. This difference may account for at least part of the difference in susceptibility of alfalfa(sensitive) and barley (tolerant) to the herbicide. Alfalfa roots always contained a much greater proportion of the total amount of picloram in the plant than did barley roots.

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Absorption and Penetration of Picloram in Potato Tuber Discs

Cited by 12 publications

References 7 publications

Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues

Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues

Environment and Spray Additive Effects on Picloram Absorption and Translocation in Leafy Spurge (Euphorbia esula)

Uptake of picloram by roots of alfalfa and barley

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Absorption and Penetration of Picloram in Potato Tuber Discs

Cited by 12 publications

References 7 publications

Uptake, Cellular Distribution, and Metabolism of 14C‐picloram by Excised Plant Tissues

Uptake, Cellular Distribution, and Metabolism of 14C‐picloram by Excised Plant Tissues

Environment and Spray Additive Effects on Picloram Absorption and Translocation in Leafy Spurge (Euphorbia esula)

Uptake of picloram by roots of alfalfa and barley

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Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues

Uptake, Cellular Distribution, and Metabolism of ¹⁴C‐picloram by Excised Plant Tissues