Abstract
Abstract The influence of a number of commercial nonionic polyoxyethylene surfactants on the foliar penetration and movement of two systemic fungicides, ethirimol and diclobutrazol, was studied in outdoor‐grown wheat plants at different growth stages and post‐treatment temperatures in two consecutive growing seasons. Both fungicides were applied as ca 0·2 μl droplets of aqueous suspension formulations containing 0·5 g litre −1 of 14 C‐labelled active ingredient; surfactants were added to these suspensions at concentrations ranging from 0·2‐10 g litre −1 . To achieve optimum uptake of each fungicide the use of surfactants with different physicochemical properties was required. For diclobutrazol, a lipophilic compound, uptake of radiolabel was best with surfactants of low mean molar ethylene oxide (E) content (5‐6) but it was necessary to use concentrations of ca 5 g litre −1 to attain this. The surfactant threshold concentration for uptake enhancement of radiolabel from ethirimol formulations (< 2 g litre −1 ) was much lower than that for diclobutrazol but surfactants with E contents > 10 induced the greatest amount of uptake. For both fungicides, surfactants with an aliphatic alcohol hydrophobe were generally more efficient in promoting their uptake than those with a nonylphenol moiety. The sorbitan‐based surfactant ‘Tween 20’ proved to be an effective adjuvant only for the ethirimol formulation; the uptake enhancing properties of the block copolymer ‘Synperonic PE/F68’ were weak. Uptake performance could not be related to the spreading properties of the respective formulations on the wheat leaf surface or to differences in solubilisation of the two fungicides by the surfactants. Although surfactants could substantially increase the amount of acropetal transport of radiolabel from both fungicides, none of those tested specifically promoted it; a constant proportion of the radioactive dose absorbed by a treated leaf was usually exported away from the site of application. The results are discussed in the light of current theories about the mode of action of surfactants as spray adjuvants.
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Claims 11
Claim · model-written summary
Optimal uptake required surfactants with different properties for the two fungicides.
- Taxon
- wheat
Triticum aestivumt0 - Outcome
- optimum uptakee0
- Qualifier
- different physicochemical propertiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To achieve optimum uptake of each fungicide the use of surfactants with different physicochemical properties was required.”
t0“wheat leaves”
Claim · model-written summary
Diclobutrazol uptake was best with low-E surfactants at about 5 g per litre.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- surfactants of low mean molar ethylene oxide (E) content (5‐6)e0
- Outcome
- uptake of radiolabele0
- Direction
- beste0
- Value
- ca 5 g litre −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For diclobutrazol, a lipophilic compound, uptake of radiolabel was best with surfactants of low mean molar ethylene oxide (E) content (5‐6) but it was necessary to use concentrations of ca 5 g litre −1 to attain this.”
t0“wheat leaves”
Claim · model-written summary
Ethirimol uptake enhancement had a lower surfactant threshold than diclobutrazol.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- surfactant threshold concentration for uptake enhancement of radiolabele0
- Direction
- much lowere0
- Value
- < 2 g litre −1e0
- Comparator
- diclobutrazole0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The surfactant threshold concentration for uptake enhancement of radiolabel from ethirimol formulations (< 2 g litre −1 ) was much lower than that for diclobutrazol”
t0“wheat leaves”
Claim · model-written summary
Surfactants with E contents above 10 induced the greatest ethirimol uptake.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- surfactants with E contents > 10e0
- Outcome
- uptakee0
- Direction
- greateste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“surfactants with E contents > 10 induced the greatest amount of uptake”
t0“wheat leaves”
Claim · model-written summary
Aliphatic alcohol surfactants generally promoted uptake more efficiently than nonylphenol surfactants.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- surfactants with an aliphatic alcohol hydrophobee0
- Outcome
- their uptakee0
- Direction
- more efficiente0
- Comparator
- those with a nonylphenol moietye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For both fungicides, surfactants with an aliphatic alcohol hydrophobe were generally more efficient in promoting their uptake than those with a nonylphenol moiety.”
t0“wheat leaves”
Claim · model-written summary
Tween 20 enhanced uptake only from the ethirimol formulation.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- ‘Tween 20’e0
- Outcome
- effective adjuvante0
- Qualifier
- only for the ethirimol formulatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The sorbitan‐based surfactant ‘Tween 20’ proved to be an effective adjuvant only for the ethirimol formulation”
t0“wheat leaves”
Claim · model-written summary
Synperonic PE/F68 had weak uptake enhancement.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- ‘Synperonic PE/F68’e0
- Outcome
- uptake enhancing propertiese0
- Direction
- weake0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the uptake enhancing properties of the block copolymer ‘Synperonic PE/F68’ were weak.”
t0“wheat leaves”
Claim · model-written summary
Uptake performance was unrelated to formulation spreading on wheat leaves.
- Taxon
- wheatTriticum aestivume0
- Treatment
- spreading properties of the respective formulationse0
- Outcome
- Uptake performancee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Uptake performance could not be related to the spreading properties of the respective formulations on the wheat leaf surface”
Claim · model-written summary
Uptake performance was unrelated to surfactant solubilisation of the fungicides.
- Taxon
- wheatTriticum aestivume0
- Treatment
- differences in solubilisation of the two fungicides by the surfactantse0
- Outcome
- Uptake performancee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Uptake performance could not be related to the spreading properties of the respective formulations on the wheat leaf surface or to differences in solubilisation of the two fungicides by the surfactants.”
Claim · model-written summary
Surfactants substantially increased acropetal transport of radiolabel.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- surfactantse0
- Outcome
- amount of acropetal transport of radiolabele0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“surfactants could substantially increase the amount of acropetal transport of radiolabel from both fungicides”
t0“wheat leaves”
Claim · model-written summary
No tested surfactant specifically promoted acropetal transport.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- constant proportion of the radioactive dose absorbed by a treated leaf was usually exported away from the site of applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“none of those tested specifically promoted it; a constant proportion of the radioactive dose absorbed by a treated leaf was usually exported away from the site of application.”
t0“wheat leaves”
The same questions in other papers
surfactant · nutrient: content · Triticum aestivum (wheat)Positive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
7 papers more in this group
See all 11 papers →polysorbate 20 · molecular: metabolites · Triticum aestivum (wheat)Results agree
1 paper in the same direction as this paper
- positive
oxirane · nutrient: content · Triticum aestivum (wheat)Results agree
2 papers in the same direction as this paper
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.