scholarly journals Interaction of surfactants with barley leaf surfaces: time-dependent recovery of contact angles is due to foliar uptake of surfactants

Planta ◽  
2021 ◽  
Vol 255 (1) ◽  
Author(s):  
Johanna Baales ◽  
Viktoria V. Zeisler-Diehl ◽  
Yaron Malkowsky ◽  
Lukas Schreiber
Keyword(s):  
Leaf Surface ◽  
Pure Water ◽  
Contact Angles ◽  
Time Dependent ◽  
Alcohol Ethoxylate ◽  
Leaf Physiology ◽  
Surfactant Solutions ◽  
Surface Wax ◽  
Leaf Surfaces ◽  
Barley Leaf

Abstract Main conclusion Time-dependent contact angle measurements of pure water on barley leaf surfaces allow quantifying the kinetics of surfactant diffusion into the leaf. Abstract Barley leaf surfaces were sprayed with three different aqueous concentrations (0.1, 1.0 and 10%) of a monodisperse (tetraethylene glycol monododecyl ether) and a polydisperse alcohol ethoxylate (BrijL4). After 10 min, the surfactant solutions on the leaf surfaces were dry leading to surfactant coverages of 1, 10 and 63 µg cm−2, respectively. The highest surfactant coverage (63 µg cm−2) affected leaf physiology (photosynthesis and water loss) rapidly and irreversibly and leaves were dying within 2–6 h. These effects on leaf physiology did not occur with the lower surfactant coverages (1 and 10 µg cm−2). Directly after spraying of 0.1 and 1.0% surfactant solution and complete drying (10 min), leaf surfaces were fully wettable for pure water and contact angles were 0°. Within 60 min (0.1% surfactant) and 6 h (1.0% surfactant), leaf surfaces were non-wettable again and contact angles of pure water were identical to control leaves. Scanning electron microscopy investigations directly performed after surfactant spraying and drying indicated that leaf surface wax crystallites were partially or fully covered by surfactants. Wax platelets with unaltered microstructure were fully visible again within 2 to 6 h after treatment with 0.1% surfactant solutions. Gas chromatographic analysis showed that surfactant amounts on leaf surfaces continuously disappeared over time. Our results indicate that surfactants, applied at realistic coverages between 1 and 10 µg cm−2 to barley leaf surfaces, leading to total wetting (contact angles of 0°) of leaf surfaces, are rapidly taken up by the leaves. As a consequence, leaf surface non-wettability is fully reappearing. An irreversible damage of the leaf surface fine structure leading to enhanced wetting and increased foliar transpiration seems highly unlikely at low surfactant coverages of 1 µg cm−2.

scholarly journals Foliar-Applied Surfactants and Urea Temporarily Reduce Carbon Assimilation of Grapefruit Leaves

2001 ◽  
Vol 126 (4) ◽  
pp. 486-490 ◽  
Author(s):  
Vladimir Orbovic ◽  
John L. Jifon ◽  
James P. Syvertsen
Keyword(s):  
Penetration Rate ◽  
Carbon Assimilation ◽  
Contact Angles ◽  
Poncirus Trifoliata ◽  
Citrus Paradisi ◽  
Inhibitory Effects ◽  
Surfactant Solutions ◽  
Leaf Surfaces ◽  
Net Assimilation ◽  
Underlying Mechanisms

Although urea can be an effective adjuvant to foliar sprays, we examined effects of additional surfactants on urea penetration through leaf cuticles along with the effect of urea with and without surfactants on net gas exchange of leaves of `Marsh' grapefruit (Citrus paradisi Macf.) trees budded to Carrizo citrange (C. sinensis L. Osbeck × Poncirus trifoliata L. Raf.) rootstock. Various combinations of urea, a nonionic surfactant (X-77), and an organosilicone surfactant (L-77), were applied to grapefruit leaves and also to isolated adaxial cuticles. When compared to X-77, L-77 exhibited superior surfactant features with smaller contact angles of droplets deposited on a teflon slide. Both L-77 and X-77 initially increased penetration rate of urea through cuticles, but the effect of X-77 was sustained for a longer period of time. The total amount of urea which penetrated within a 4-day period, however, was similar after addition of either surfactant. Solutions of either urea, urea + L-77, urea + X-77, or L-77 alone decreased net assimilation of CO2 (ACO2) for 4 to 24 hours after spraying onto grapefruit leaves. A solution of X-77 alone had no effect on ACO2 over the 4-day period. Although reductions in ACO2 were similar following sprays of urea formulated with two different surfactants, the underlying mechanisms may not have been the same. For the urea + X-77 treatment, X-77 increased the inhibitory effects of urea on ACO2 indirectly by increasing penetration of urea into leaves. For the urea + L-77 formulation, effects of L-77 on ACO2 were 2-fold, direct by inhibiting ACO2 and indirect by increasing urea penetration. One hour after application, scanning electron microscopy (SEM) of leaf surfaces treated with X-77 revealed that they were heavily coated with the residue of the surfactant, whereas leaves treated with L-77 looked similar to nontreated leaves with no apparent residues on their surfaces. The amount of X-77 residue on the leaves was lower 24 hours after application than after 1 hour as observed by SEM.

scholarly journals Surfactant-induced enhancement of droplet adhesion in superhydrophobic soybean (Glycine max L.) leaves

2017 ◽  
Vol 8 ◽  
pp. 2345-2356 ◽  
Author(s):  
Oliver Hagedorn ◽  
Ingo Fleute-Schlachter ◽  
Hans Georg Mainx ◽  
Viktoria Zeisler-Diehl ◽  
Kerstin Koch
Keyword(s):  
Glycine Max ◽  
Leaf Surface ◽  
Pure Water ◽  
Epicuticular Wax ◽  
Hierarchical Organization ◽  
Water Contact ◽  
Hydrophilic Lipophilic Balance ◽  
Leaf Surfaces ◽  
Before And After ◽  
Soybean Leaf

This study performed with soybean (Glycine max L.), one of the most important crops for human and animal nutrition, demonstrates that changes in the leaf surface structure can increase the adhesion of applied droplets, even on superhydrophobic leaves, to reduce undesirable soil contamination by roll-off of agrochemical formulations from the plant surfaces. The wettability and morphology of soybean (Glycine max L.) leaf surfaces before and after treatment with six different surfactants (Agnique® SBO10 and five variations of nonionic surfactants) have been investigated. The leaf surface structures show a hierarchical organization, built up by convex epidermal cells (microstructure) and superimposed epicuticular platelet-shaped wax crystals (micro- to nanostructure). Chemical analysis of the epicuticular wax showed that 1-triacontanol (C30H61OH) is the main wax component of the soybean leaf surfaces. A water contact angle (CA) of 162.4° (σ = 3.6°) and tilting angle (TA) of 20.9° (σ = 10.0°) were found. Adherence of pure water droplets on the superhydrophobic leaves is supported by the hydrophilic hairs on the leaves. Agnique® SBO10 and the nonionic surfactant XP ED 75 increased the droplet adhesion and caused an increase of the TA from 20.9° to 85° and 90°, respectively. Scanning electron microscopy showed that surfactants with a hydrophilic–lipophilic balance value below 10 caused a size reduction of the epicuticular wax structures and a change from Cassie–Baxter wetting to an intermediate wetting regime with an increase of droplet adhesion.

Spread of Paraffinic Oil on Leaf Surfaces of Johnsongrass (Sorghum halepense)

Weed Science ◽  
1988 ◽  
Vol 36 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Chester G. McWhorter ◽  
William L. Barrentine
Keyword(s):  
Soybean Oil ◽  
Leaf Surface ◽  
Sorghum Halepense ◽  
Complete Coverage ◽  
Mode Of Entry ◽  
Surface Wax ◽  
Leaf Surfaces ◽  
Water Sprays ◽  
Paraffinic Oil ◽  
Leaf Surface Wax

Paraffinic oil applied at 2.3, 4.7, and 9.3 L/ha to the surface of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] leaves spread to provide complete coverage of the leaf surface. Soybean oil applied at the same volumes provided only 30 to 50% coverage of leaf surfaces. Water at 187 L/ha that contained 1.25% paraffinic oil adjuvant provided only about 30% coverage because spray droplets did not spread appreciably. Spread coefficients obtained when five different oil-soluble herbicides were applied to leaf surfaces in paraffinic oil were more than 100 times greater than when applied in water alone. Higher spread coefficients were obtained when paraffinic oil contained herbicides than when paraffinic oil was applied alone. Spread coefficients were also much greater for paraffinic oil alone than for soybean oil with or without herbicides. Stomata on johnsongrass leaves were distorted by paraffinic oil, suggesting that leaf surface wax was dissolved and this might be a mode of entry of herbicide into johnsongrass when applied in paraffinic oil. Stomata were unaffected by soybean oil or by water sprays that contained 1.25% soybean oil adjuvant or paraffinic oil adjuvant.

scholarly journals Effect of Surfactant Compound Sprays on The Rate of Adsorption on Different Target Surfaces

2019 ◽  
Vol 10 ◽  
pp. 1834-1845
Author(s):  
Muhammed Cemal Toraman ◽  
Ali Bayat
Keyword(s):  
Active Substance ◽  
Negative Impact ◽  
Pure Water ◽  
Contact Angles ◽  
Surface Active Substance ◽  
Drop Shape ◽  
Leaf Surfaces ◽  
Surface Active ◽  
Spreading Rates ◽  
Active Substances

The first operation of adsorption on leaf surfaces in pulverization is drop sticking. In the water wettability of the surfaces, the sticking of the drops has a great importance. Drop contact angle, contact height, and contact diameter values in the third and tenth seconds were measured with Drop Shape Analysis 10 device to determine adsorption, spreading, and sticking levels by applying mixtures of ten surface active substances including different contents with pure water to different leaf surfaces. The adsorption and sticking rates of the drops they formed on different leaf surfaces were determined for the time they are obtained from the data obtained in both time periods. Furthermore, the spreading rates of the mixtures prepared by taking into account the change rates during the last seven seconds between these two periods were determined as the sticking rate. Coating shares related to covering rates of different surface active substances with different surface properties on the surface of leaves were evaluated as possible work success according to the adsorption, spreading and sticking levels anticipated in spraying. According to their results on the application surfaces, surface active substances and leaves were evaluated statistically by the SPSS 15 program in terms of their similar properties. It has been found that surface active substance mixtures with sodium carboxymethylcellulose and carboxymethylcellulose contents had the largest drop contact angles and contact heights with the smallest drop contact diameters on the leaf surfaces, and a negative impact on the adsorption performance as they spread very little over seven seconds. It has been determined that drops with surface active substance including trisiloxane + allyloxypolyethyleneglycol and alcoholethoxylate, alkylphenolethoxylate have formed the smallest contact angles, minimum drop heights and largest contact diameters on the surface of the leaves, as well as increased adsorption and sticking by spreading rapidly for seven seconds.

scholarly journals Infra-Specific Variation in Wax on Leaf Surfaces

1965 ◽  
Vol 18 (2) ◽  
pp. 323 ◽  
Author(s):  
DM Hall ◽  
AI Matus ◽  
JA Lamberton ◽  
HN Barber
Keyword(s):  
Electron Microscope ◽  
Light Scattering ◽  
Pisum Sativum ◽  
Leaf Surface ◽  
Chemical Data ◽  
Surface Wax ◽  
Leaf Surfaces ◽  
Specific Variation ◽  
Wax Deposits ◽  
Cuticular Surface

The structure of the surfaCe wax on green and glaucous variants in Eucalyptus urnigera, Poa colensoi (natural cline forms), Pisum sativum, and BraBsica oleracea (mutants) are described as seen under the electron microscope. Preliminary chemical data are also given. The green forms always possess wax deposits which are either smooth films on the cuticle or consist predominantly of platelets which lie flat on the cuticular surface. In some cases the platelets tend to be arranged in parallel groups. In the glaucous variants, the wax consists predominantly of rods or filaments growing outwards from the leaf surface and presenting many light-scattering surfaces.

scholarly journals Time-dependent Dynamic Receding Contact Angles Studied during the Flow of Dilute Aqueous Surfactant Solutions through Fluorinated Microtubes

2012 ◽  
Vol 41 (10) ◽  
pp. 1232-1234 ◽  
Author(s):  
Manos Anyfantakis ◽  
Daniela Fell ◽  
Hans-Jürgen Butt ◽  
Günter K. Auernhammer
Keyword(s):  
Contact Angles ◽  
Time Dependent ◽  
Surfactant Solutions ◽  
Receding Contact

scholarly journals Study on contact angles and surface energy of MXene films

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5512-5520
Author(s):  
Hang Zhou ◽  
Fuqiang Wang ◽  
Yuwei Wang ◽  
Changping Li ◽  
Changrui Shi ◽  
...  
Keyword(s):  
Surface Energy ◽  
Contact Angles ◽  
Time Dependent ◽  
Wetting Behaviors

This work sheds light on the process- and time-dependent wetting behaviors and surface energy of MXene films.

Particle size, leaf pubescence and condition of humidity at leaf surfaces are key factors determining the retention of volcanic ash on crop foliage.

2021 ◽  
Author(s):  
Noa Ligot ◽  
Benoît Pereira ◽  
Patrick Bogaert ◽  
Guillaume Lobet ◽  
Pierre Delmelle
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Leaf Surface ◽  
Volcanic Risk ◽  
Chilli Pepper ◽  
Leaf Pubescence ◽  
Leaf Surfaces ◽  
Plant Foliage ◽  
Leaf Surface Area ◽  
Ash Deposit

<p>Volcanic ashfall negatively affects crops, causing major economic losses and jeopardising the livelihood of farmers in developing countries where agriculture is at volcanic risk. Ash on plant foliage reduces the amount of incident light, thereby limiting photosynthesis and plant yield. An excessive ash load may also result in mechanical plant damages, such as defoliation and breakage of the stem and twigs. Characterising crop vulnerability to ashfall is critical to conduct a comprehensive volcanic risk analysis. This is normally done by describing the relationship between the ash deposit thickness and the corresponding reduction in crop yield, i.e. a fragility function. However, ash depth measured on the ground surface is a crude proxy of ash retention on plant foliage as this metrics neglects other factors, such as ash particle size, leaf pubescence and condition of humidity at leaf surfaces, which are likely to influence the amount of ash that stays on leaves.</p><p>Here we report the results of greenhouse experiments in which we measured the percentage of leaf surface area covered by ash particles for one hairy leaf plant (tomato, Solanum lycopersicum L.) and one hairless leaf plant (chilli pepper, Capsicum annuum L.) exposed to simulated ashfalls. We tested six particle size ranges (≤ 90, 90-125, 125-250, 250-500, 500-1000, 1000-2000 µm) and two conditions of humidity at leaf surfaces, i.e. dry and wet. Each treatment consisted of 15 replicates. The tomato and chilli pepper plants exposed to ash were at the seven- and eight-leaf stage, respectively. An ash load of ~570 g m<sup>-2 </sup>was applied to each plant using a homemade ashfall simulator. We estimated the leaf surface area covered by ash from pictures taken before and immediately after the simulated ashfall. The ImageJ software was used for image processing and analysis.</p><p>Our results show that leaf coverage by ash increases with decreasing particle size. Exposure of tomato and chilli pepper to ash ≤ 90 μm always led to ~90% coverage of the leaf surface area. For coarser particles sizes (i.e. between 125 and 500 µm) and dry condition at leaf surfaces, a significantly higher percentage (on average 29 and 16%) of the leaf surface area was covered by ash in the case of tomato compared to chilli pepper, highlighting the influence of leaf pubescence on ash retention. In addition, for particle sizes between 90 and 500 µm, wetting of the leaf surfaces prior to ashfall enhanced the ash cover by 19 ± 5% and 34 ± 11% for tomato and chilli pepper, respectively.</p><p>These findings highlight that ash deposit thickness alone cannot describe the hazard intensity accurately. A thin deposit of fine ash (≤ 90 µm) will likely cover the entire leaf surface area, thereby eliciting a disproportionate effect on plant foliage compared to a thicker but coarser deposit. Similarly, for a same ash depth, leaf pubescence and humid conditions at the leaf surfaces will enhance ash retention, thereby increasing the likelihood of damage. Our study will contribute to improve the reliability of crop fragility functions used in volcanic risk assessment.</p>

Lack of Internalization of Escherichia coli O157:H7 in Lettuce (Lactuca sativa L.) after Leaf Surface and Soil Inoculation

2009 ◽  
Vol 72 (10) ◽  
pp. 2028-2037 ◽  
Author(s):  
GUODONG ZHANG ◽  
LI MA ◽  
LARRY R. BEUCHAT ◽  
MARILYN C. ERICKSON ◽  
VANESSA H. PHELAN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Lactuca Sativa L ◽  
Leaf Surfaces ◽  
Leaves And Roots ◽  
Leaf Lettuce

Survival and internalization characteristics of Escherichia coli O157:H7 in iceberg, romaine, and leaf lettuce after inoculation of leaf surfaces and soil were determined. A five-strain mixture of E. coli O157:H7 in water and cow manure extract was used as an inoculum for abaxial and adaxial sides of leaves at populations of 6 to 7 log and 4 log CFU per plant. The five strains were individually inoculated into soil at populations of 3 and 6 log CFU/g. Soil, leaves, and roots were analyzed for the presence and population of E. coli O157:H7. Ten (4.7%) of 212 samples of leaves inoculated on the adaxial side were positive for E. coli O157:H7, whereas 38 (17.9%) of 212 samples inoculated on the abaxial side were positive. E. coli O157:H7 survived for at least 25 days on leaf surfaces, with survival greater on the abaxial side of the leaves than on the adaxial side. All 212 rhizosphere samples and 424 surface-sanitized leaf and root samples from plants with inoculated leaves were negative for E. coli O157:H7, regardless of plant age at the time of inoculation or the location on the leaf receiving the inoculum. The pathogen survived in soil for at least 60 days. Five hundred ninety-eight (99.7%) of 600 surface-sanitized leaf and root samples from plants grown in inoculated soil were negative for E. coli O157:H7. Internalization of E. coli O157:H7 in lettuce leaves and roots did not occur, regardless of the type of lettuce, age of plants, or strain of E. coli O157:H7.

Tribological research of leaf-surface wax derived from plants of Pinaceae

2018 ◽  
Vol 31 (1-2) ◽  
pp. 1-10 ◽  
Author(s):  
Xin Feng ◽  
Yichao Hu ◽  
Yanqiu Xia
Keyword(s):  
Leaf Surface ◽  
Surface Wax ◽  
Leaf Surface Wax
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