Interaction of Surfactant and Leaf Surface in Glyphosate Absorption

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Moritz Knoche ◽  
Martin J. Bukovac
Keyword(s):  
Fine Structure ◽  
Chain Length ◽  
Homologous Series ◽  
Nonionic Surfactants ◽  
Leaf Surface ◽  
Droplet Evaporation ◽  
Foliar Uptake ◽  
Adaxial Surface ◽  
Adaxial Leaf Surface ◽  
Leaf Surfaces

The effect of oxyethylene (OE) chain length of three homologous series of nonionic surfactants (allinol, nonoxynol, octoxynol) on glyphosate uptake was markedly affected by the leaf surface fine-structure of sugarbeet and kohlrabi. Adaxial leaf surfaces of sugarbeet were covered with a layer of amorphous wax, whereas the adaxial surface of kohlrabi leaves was covered with fine crystalline wax. Foliar uptake of glyphosate (1 mM glyphosate, 20 mM glycine, pH 3.2) averaged 4% for sugarbeet without surfactant, but droplets were not retained by kohlrabi leaves in the absence of a surfactant. Glyphosate absorption with octoxynol (9 to 10 OE units, 0.5 g L−1) was rapid initially (0 to 2 h) and leveled off about 2 h after application in both species. Absorption by sugarbeet decreased from 12 to 3% as OE content of octoxynol was increased from 5 to 30 OE units. In contrast, surfactants of intermediate OE content (octoxynol, 16 OE units) induced the greatest uptake (17%) on kohlrabi. Leaf wetting was markedly affected by surfactant and leaf surface. As OE content of octoxynol increased from 5 to 30 OE units, droplet/leaf interface areas of 1-μl droplets decreased from 4 to 3 mm2 on the adaxial leaf surface of sugarbeet and from 61 to 2 mm2 on kohlrabi. Concurrently, the rate of droplet evaporation (1 μl) decreased from 1.0 to 0.7 nl s−1 on sugarbeet and 4.2 to 0.5 nl s−1 on kohlrabi leaves. The effect of OE content on enhancement of glyphosate uptake and wetting characteristics of spray solutions was similar within species for different hydrophobic moieties but differed markedly between species.

scholarly journals Distribution pattern of arthropods on the leaf surfaces of Acacia auriculiformis saplings

2023 ◽  
Vol 83 ◽  
Author(s):  
L. F. Silva ◽  
F. W. S. Silva ◽  
G. L. Demolin-Leite ◽  
M. A. Soares ◽  
P. G. Lemes ◽  
...  
Keyword(s):  
Leaf Surface ◽  
Acacia Auriculiformis ◽  
Phytophagous Insects ◽  
Adaxial Surface ◽  
Adaxial Leaf Surface ◽  
Arthropod Predators ◽  
Leaf Surfaces ◽  
Management Plans ◽  
Tetragonisca Angustula ◽  
Taxonomic Groups

Abstract Acacia auriculiformis A. Cunn. Ex Benth. (Fabaceae), a non-native pioneer species in Brazil with fast growth and rusticity, is used in restoration programs. Our goal was to assess during a 24-month survey the pattern of arthropods (phytophagous insects, bees, spiders, and predator insects) on the leaf surfaces of A. auriculiformis saplings. Fourteen species of phytophagous, two of bees and eleven of predators were most abundant on the adaxial surface. The values of the ecological indexes (abundance, diversity, and species richness) and the rarefaction, and k-dominance curves of phytophagous, bees and arthropod predators were highest on the adaxial leaf surface of A. auriculiformis. The k-dominance and abundance of Aleyrodidae (Hemiptera) (both leaf surfaces), the native stingless bee Tetragonisca angustula Latreille (Hymenoptera: Apidae) (both leaf surfaces) and the ant Brachymyrmex sp. (adaxial surface) and Pheidole sp. (Hymenoptera: Formicidae) (abaxial surface) were the highest between the taxonomic groups of phytophagous, bees, and predators, respectively on A. auriculiformis saplings. The ecological indexes and rarefaction, abundance, and k-dominance curves of phytophagous insects, bees, and predators were highest on the adaxial leaf surface. The preference of phytophagous insects for the adaxial leaf surface is probably due to the lower effort required to move on this surface. Understanding the arthropod preferences between leaf surfaces may help to develop sampling and pest management plans for the most abundant phytophagous insects on A. auriculiformis saplings. Also, knowledge on the preference pattern of bees and predators may be used to favour their conservation.

scholarly journals ROSE LEAF SURFACE - BLACKSPOT DISEASE RESISTANCE: A SCANNING ELECTRON MICROSCOPE VIEW

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1093f-1093
Author(s):  
K.S. Reddy ◽  
S.E. Newman ◽  
J.A. Spencer ◽  
R.N. Paul
Keyword(s):  
Fine Structure ◽  
Leaf Surface ◽  
Physical Nature ◽  
Fungal Spore ◽  
Dynamic Nature ◽  
Diplocarpon Rosae ◽  
Leaf Surfaces ◽  
Visual Concepts ◽  
Resistant Genotypes ◽  
Scanning Electron

Blackspot disease, caused by Diplocarpon rosae, is a devastating disease of garden roses. Most hybrid teas and floribundas are susceptible to this disease in contrast to many species roses, which are resistant. The basis of this resistance is not known. The first barrier to invasion by the pathogen is the outer surface of the leaf. The physical nature of this surface may influence the attempted infection, landing, germination and penetration by the fungal spore and may cause a failure of infection. The leaf surfaces of susceptible and resistant genotypes were observed using SEM that allowed examination of the fine structure of the leaf surface. The characteristics of the leaf surface topography including wax structures were pictorially compared and visual concepts developed in relation to the dynamic nature of the leaf surface in space and time as leaf is infected by the pathogen.

scholarly journals SPRAY DROPLET/CHEMICAL DEPOSIT INTERACTION WITH LEAF SURFACES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1146a-1146
Author(s):  
M.J. Bukovac ◽  
D.L. Reichard
Keyword(s):  
Fine Structure ◽  
Growth Regulators ◽  
Leaf Surface ◽  
Crop Protection ◽  
Chemical Deposition ◽  
Lateral Diffusion ◽  
Tween 20 ◽  
Spray Droplet ◽  
Leaf Surfaces ◽  
Droplet Drying

Most growth regulators and crop protection chemicals are delivered to the plant as aqueous sprays. Spray droplet:plant surface interaction is central to establishing spray and, hence, dose retention by the plant. Further, the nature of chemical deposition from spray droplets plays an important role in determining the efficiency of the active ingredient (a.i.). Using scanning electron microscopy and dispersive x-ray analysis, we investigated chemical deposit formation of selected growth regulators (e.g. ethephon, 2,4, 5-TP, TIBA) on leaf surfaces differing in wettability and surface fine-structure. The a.i. frequently deposited in the form of an annulus on droplet drying, and the degree of spreading was related to surface tension of the spray solution, and wettability, fine-structure and morphology of the leaf surface. Marked differences were observed in spreading following impaction on veins vs. interveinal areas of leaves of Prunus and Pyrus sp. The epidermis over veins was more readily wetted leading to rapid lateral diffusion along veins. Surfactants (e.g. Tween 20, Regulaid) altered the deposition pattern, expanding the annulus and increasing spreading on the leaf surface.

scholarly journals Ingestion of Novaluron Elicits Transovarial Activity in Stephanitis pyrioides (Hemiptera: Tingidae)

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 216 ◽  
Author(s):  
Shimat V. Joseph
Keyword(s):  
Leaf Surface ◽  
Control Strategies ◽  
Insect Pest ◽  
Ornamental Plants ◽  
Insect Growth Regulator ◽  
Adaxial Surface ◽  
Nontarget Effects ◽  
Adaxial Leaf Surface ◽  
Significant Difference ◽  
The Usa

Azaleas (Rhododendron L. spp.) are widely grown ornamental plants in eastern and western regions of the USA. The azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is an important insect pest of azaleas. Adults and nymphs of S. pyrioides consume chlorophyll in azalea foliage, and severely affected plants appear bleached. Neonicotinoid insecticides are effective and widely used for S. pyrioides control; however, nursery growers and landscape professionals are concerned about nontarget effects on beneficial insects and demand neonicotinoid-free plants. There is clearly a need to develop reduced-risk control strategies for S. pyrioides. The insect growth regulator (IGR) novaluron elicits transovarial activity when adult S. pyrioides are exposed to it. However, it is not certain whether transovarial effects can be observed when S. pyrioides adults that colonize the abaxial leaf surface ingest novaluron residues deposited on the adaxial leaf surface. Experiments were conducted to assess transovarial activity upon exposure to various application rates of novaluron alone and novaluron with various adjuvants. The numbers of nymphs were significantly lower when the full rate of novaluron was applied on the adaxial surface of leaves compared to the number of nymphs on non-treated leaves. The densities of nymphs were not significantly different between the half and full rates of novaluron treatment. When novaluron with various adjuvants was applied to the adaxial surface of the leaves, the densities of nymphs were significantly lower under the novaluron treatments compared to the non-treated leaves, regardless of the type of adjuvant added. There was no significant difference between treatment with novaluron alone and the treatments of novaluron with adjuvants. These data show that transovarial activity was elicited in adults of S. pyrioides when novaluron was applied on the adaxial leaf surface.

Influence of leaf surface micromorphology, wax content, and surfactant on primisulfuron droplet spread on barnyardgrass (Echinochloa crus-galli) and green foxtail (Setaria viridis)

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 627-633 ◽  
Author(s):  
Debanjan Sanyal ◽  
Prasanta C. Bhowmik ◽  
Krishna N. Reddy
Keyword(s):  
Leaf Area ◽  
Leaf Surface ◽  
Unit Area ◽  
Wetting Agent ◽  
Adaxial Leaf Surface ◽  
Green Foxtail ◽  
Abaxial Leaf Surface ◽  
Leaf Surfaces ◽  
Spread Area ◽  
Wax Content

Laboratory studies were conducted to examine the leaf surface, epicuticular wax content, and spread area of primisulfuron spray droplet with and without surfactant on leaf surface of barnyardgrass and green foxtail. Adaxial and abaxial leaf surfaces were examined using scanning electron microscopy and leaf wax was extracted and quantified. The spread of 1-μl droplets of distilled water, primisulfuron solution (without surfactant), primisulfuron solution with a nonionic low foam wetter/spreader adjuvant (0.25% v/v), and with an organosilicone wetting agent (0.1% v/v) was determined on the adaxial leaf surfaces of each of the weed species. Stomata and trichomes were present on adaxial and abaxial leaf surfaces in both species. Green foxtail had more stomata per unit area on the adaxial as compared to the abaxial leaf surface. Barnyardgrass had more stomata on the abaxial than on the adaxial leaf surface. There was no significant variation in the number of trichomes per unit leaf area of green foxtail, and the number of prickles per unit area of leaf was significantly higher in adaxial than the abaxial leaf surface, in both young and old leaves. In barnyardgrass, there were more trichomes on abaxial than adaxial leaf surface. The mean value of the wax content per unit of leaf area in barnyardgrass and green foxtail was 35.9 μg cm−2and 19.1 μg cm−2, respectively. On both species primisulfuron with a nonionic surfactant had more spread area than that without a surfactant, and the spread was even greater with organosilicone wetting agent. The spread area of primisulfuron droplet was higher on the leaf surface of barnyardgrass than on green foxtail when surfactant was added.

Surface Energies of Nonionic Surfactants Adsorbed onto Nylon Fiber and a Correlation with Their Solubility Parameters

1992 ◽  
Vol 62 (9) ◽  
pp. 535-546 ◽  
Author(s):  
Philip E. Slade ◽  
Debra N. Hild
Keyword(s):  
Homologous Series ◽  
Nonionic Surfactants ◽  
Solubility Parameters ◽  
Nylon 66 ◽  
Synthetic Fibers ◽  
Surface Energies ◽  
Nylon Fiber

The surface energies of spin finishes adsorbed onto synthetic fibers are a major factor in determining the processing capabilities of these fibers. They also play a key role in determining how wettable the fibers are by other materials that may be applied to yarn or fabrics in later stages of processing, such as dyes, sizes, or anti-soiling agents. We have applied several homologous series of nonionic surfactants, which can be used as spin finish emulsifiers, to nylon 66 fibers and determined the polar, dispersion, and total surface energies of these adsorbed materials. We also propose a relationship between the measured surface energies and the calculated Hansen fractional solubility parameters.

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.

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