Foliar Surface Research Articles

First Report on Taxonomic Significance of Foliar Microanatomy of Lamiaceae Taxa from Pakistan; A Correct Tool for Taxa Authentication

The foliar epidermal, stomatal and trichome properties are frequently used as plant microscopic attributes from a taxonomic or ecological perspective. Among the angiosperm families, the Lamiaceae is one of the most taxonomically difficult, economically significant, and medicinally important families. To better understand the foliar microanatomy of Lamiaceae taxa obtained from Northern Pakistan, this study attempts to determine the variational and diagnostic features of 27 species that were analyzed using light microscopy (LM) and scanning electron microscopy (SEM). UPGMA cluster analysis, principal component analysis (PCA) and semantic differential chart (SDC) were used to characterize, visualize, and compare the leaf micromorphology across all species. Three different types of epidermal cell types were examined on both foliar surfaces i.e., irregular, hexagonal, and polygonal. Anticlinal wall pattern also shows variation. Anomocytic stomata is dominant in 8 studied species followed by paractic in 5 species, anisocytic in 4 species and diacytic in 2 species. The trichomes could be broadly classified into two groups, glandular trichomes (GTs) and non-glandular trichomes (NGTs). Lamiaceae has two types of glandular trichomes, small capitate and large peltate, which differ in size, structure, and distribution. In present research five distinct forms of non-glandular trichomes are unicellular, multicellular, stellate, branched, and unbranched trichomes. The results that characterized, illustrated, and contrasted the leaf anatomical characteristics of the Lamiaceae taxa can be better understood with the aid of statistical analysis. Future research will depend on these findings to improve the systematics of Lamiaceae taxa. These characteristics have a large taxonomic potential when considered as a whole.

Stimuli-responsive sulfur-containing amino acid functionalized boron nitride nanosheets as nanocarriers via improved adhesion to enhance antibacterial performance against plant diseases

Bacterial wilt caused by Ralstonia solanacearum severely impacts agricultural production, urgently requiring effective control measures. Herein, we designed a strategy via boron nitride nanosheets with enhanced adhesion ability as nanocarriers to improve the antibacterial efficacy of active ingredients. To achieve this, we utilized three sulfur-containing amino acids (SAAs), including methionine (MET), cysteine (CYS), and cystine (CYST) for the simultaneously exfoliation and functionalization of boron nitride nanosheets (BNNS) through mechanochemical method, and compared their structure–activity relationship. The obtained BNNS-SAAs exhibited size around 160–250 nm and thickness near 1.5–2.0 nm. The presence of disulfide bond (S-S) within BNNS-CYS and BNNS-CYST promoted them with the responsiveness by redox stimuli. BNNS-CYST acquired highest functionalization degree of 63.44 % among three BNNS-SAAs. And tea tree essential oil (TTO) loading capacity within BNNS-SAAs was around 36.40–37.11 %. The existence of SAAs within BNNS significantly inhibited the volatilization of TTO via nanoconfinement effect fitting to Logistic model, specially, BNNS-CYST held with slowest release rate among the BN-based carriers, due to the stronger attachment or affinity. Furthermore, BNNS-CYST-TTO exhibited the most excellent synergistic antibacterial effect with the increased inhibition zone diameter by 26.89 % against Ralstonia solanacearum in comparison with pure TTO, with the minimum inhibition concentration reduced from 1.8 mg·mL−1 to 0.6 mg·mL−1. The enhanced antibacterial mechanism was proposed based on physical disruption via strong adhesion. BNNS-SAAs also presented superior adhesion and wettability on seed and foliar surfaces, and also promoted seed germination by providing more S nutrients, and exhibited no significant cytotoxicity. Our system provides a green and effective platform response to redox stimuli to load and release essential oils for application in bacterial wilt control.

Polydopamine-Modified Mesoporous Nanobottles with High Loading Capacity for Sustained Release and Retention of Kresoxim-Methyl on Foliar Surfaces

Polydopamine-Modified Mesoporous Nanobottles with High Loading Capacity for Sustained Release and Retention of Kresoxim-Methyl on Foliar Surfaces

The relationship between atmospheric particulate matter, leaf surface microstructure, and the phyllosphere microbial diversity of Ulmus L.

BackgroundPlants can retain atmospheric particulate matter (PM) through their unique foliar microstructures, which has a profound impact on the phyllosphere microbial communities. Yet, the underlying mechanisms linking atmospheric particulate matter (PM) retention by foliar microstructures to variations in the phyllosphere microbial communities remain a mystery. In this study, we conducted a field experiment with ten Ulmus lines. A series of analytical techniques, including scanning electron microscopy, atomic force microscopy, and high-throughput amplicon sequencing, were applied to examine the relationship between foliar surface microstructures, PM retention, and phyllosphere microbial diversity of Ulmus L.ResultsWe characterized the leaf microstructures across the ten Ulmus lines. Chun exhibited a highly undulated abaxial surface and dense stomatal distribution. Langya and Xingshan possessed dense abaxial trichomes, while Lieye, Zuiweng, and Daguo had sparsely distributed, short abaxial trichomes. Duomai, Qingyun, and Lang were characterized by sparse stomata and flat abaxial surfaces, whereas Jinye had sparsely distributed but extensive stomata. The mean leaf retention values for total suspended particulate (TSP), PM2.5, PM2.5-10, PM10-100, and PM> 100 were 135.76, 6.60, 20.10, 90.98, and 13.08 µg·cm− 2, respectively. Trichomes substantially contributed to PM2.5 retention, while larger undulations enhanced PM2.5-10 retention, as evidenced by positive correlations between PM2.5 and abaxial trichome density and between PM2.5-10 and the adaxial raw microroughness values. Phyllosphere microbial diversity patterns varied among lines, with bacteria dominated by Sediminibacterium and fungi by Mycosphaerella, Alternaria, and Cladosporium. Redundancy analysis confirmed that dense leaf trichomes facilitated the capture of PM2.5-associated fungi, while bacteria were less impacted by PM and struggled to adhere to leaf microstructures. Long and dense trichomes provided ideal microhabitats for retaining PM-borne microbes, as evidenced by positive feedback loops between PM2.5, trichome characteristics, and the relative abundances of microorganisms like Trichoderma and Aspergillus.ConclusionsBased on our findings, a three-factor network profile was constructed, which provides a foundation for further exploration into how different plants retain PM through foliar microstructures, thereby impacting phyllosphere microbial communities.

Towards eco-friendly plant growth regulator: A robustly stable and efficient uniconazole emulsion based on onion-like lamellar liquid crystal

As a commonly water-based pesticide formulation, conventional Emulsions in Water (EWs) always suffer from demulsification in actual complex environments and burst release due to their thermodynamic instability. The ecotoxicity and phytotoxicity caused by chemosynthetic adjuvants cannot be ignored. To address these issues, herein, using a soybean lecithin-based lamellar liquid crystal emulsion (LCE) as the carrier, we construct a robustly stable and low-toxicity EW with the “onion-like” bionic structure and achieve the efficient delivery of plant growth regulator (PGR) uniconazole (UZ). The hydrophobic UZ is firmly encapsulated within the orderly assembled Oil-in-Liquid Crystal-in-Water (O/LC/W) multilayers. This confinement endows UZ-LCE with robust stability, even while encountering disturbances such as dilution, shaking, and changes in pH, ions, and temperature. Furthermore, UZ-LCE exhibits enhanced wettability and affinity to foliar surfaces, as well as specific sustained-release ability. Owing to these superiorities of UZ-LCE, during two consecutive years of efficacy evaluations in cotton field experiments, UZ-LCEs administered through drip irrigation and foliar spray demonstrate remarkable enhancements in controlling excessive plant growth, increasing chlorophyll content, and boosting flower bud formation, surpassing the effectiveness of conventional EWs. UZ-LCE even outperforms commercial preparations (WP and SC) in balancing vegetative growth and reproductive growth, resulting in an 8.3% increase in yield. This research provides an innovative pesticide formulation with eco-friendly adjuvants, less organic solvent, and synergistic functionalities, which is prospective to be extended to other pesticide EWs and contribute to sustainable agriculture.

Vertical variation in swelling properties of Norway spruce bark depending on tree age and bark moisture content

AbstractIn forest ecosystems, interception of rainwater on foliar and woody surfaces and the subsequent partitioning into stemflow is largely controlled by physical and hydrological properties of bark. Few forest ecohydrology studies have explored the role of bark properties (e.g., thickness, density) on bark water storage capacity and stemflow production. Even fewer have explored how different phases of water (e.g., liquid, vapor) may affect bark through bark swelling properties across the stem and how the degree of swelling affects tradeoffs between bark water storage and stemflow generation. Thus, the objective of this study was to analyze changes in a bark swelling index (BSI) vertically along stems of Picea abies (Norway spruce) after exposure to both water vapor and liquid water, as a function of tree age and bark moisture content. We found that tree age influenced BSI and bark moisture content, wherein BSI was ∼ 6.5% lower in older trees (70 years) compared to younger trees (35 and 50 years), and average moisture content was 10.4–13.2% lower. BSI increased when bark was exposed to hygroscopic water vapor and reached maximum swelling after 1 day of water saturation. BSI also increased from the base of the tree to 20–30% of total tree height, beyond which BSI remained relatively stable across all age classes. Enhanced understanding of bark swelling mechanisms as a result of stem position, age, and moisture content and exposure provide stronger foundations for understanding canopy hydrologic partitioning and the fate of rainwater moving through forest canopies.

Multi-Stimuli-Responsive, Topology-Regulated, and Lignin-Based Nano/Microcapsules from Pickering Emulsion Templates for Bidirectional Delivery of Pesticides.

The increasing demand for improving pesticide utilization efficiency has prompted the development of sustainable, targeted, and stimuli-responsive delivery systems. Herein, a multi-stimuli-responsive nano/microcapsule bidirectional delivery system loaded with pyraclostrobin (Pyr) is prepared through interfacial cross-linking from a lignin-based Pickering emulsion template. During this process, methacrylated alkali lignin nanoparticles (LNPs) are utilized as stabilizers for the tunable oil-water (O/W) Pickering emulsion. Subsequently, a thiol-ene radical reaction occurs with the acid-labile cross-linkers at the oil-water interface, leading to the formation of lignin nano/microcapsules (LNCs) with various topological shapes. Through the investigation of the polymerization process and the structure of LNC, it was found that the amphiphilicity-driven diffusion and distribution of cyclohexanone impact the topology of LNC. The obtained Pyr@LNC exhibits high encapsulation efficiency, tunable size, and excellent UV shielding to Pyr. Additionally, the flexible topology of the Pyr@LNC shell enhances the retention and adhesion of the foliar surface. Furthermore, Pyr@LNC exhibits pH/laccase-responsive targeting against Botrytis disease, enabling the intelligent release of Pyr. The in vivo fungicidal activity shows that efficacy of Pyr@LNC is 53% ± 2% at 14 days postspraying, whereas the effectiveness of Pyr suspension concentrate is only 29% ± 4%, and the acute toxicity of Pyr@LNC to zebrafish is reduced by more than 9-fold compared with that of Pyr technical. Moreover, confocal laser scanning microscopy shows that the LNCs can be bidirectionally translocated in plants. Therefore, the topology-regulated bidirectional delivery system LNC has great practical potential for sustainable agriculture.

Exogenous gibberellin improves the yield and quality of basil (Ocimum basilicum L.) and chervil (Anthriscus cerefolium L.) plants grown under salinity stress conditions

Gibberellins play a crucial role as plant hormones in the regulation of various aspects of plant growth and development. They are involved in processes such as seed germination, breaking plant and bud dormancy, and counteracting the effects of auxin. Additionally, gibberellins promote leaf expansion, stimulate stem elongation, and contribute to flower development and fruit set. The objective of this study was to investigate the effects of gibberellic acid (GA3) treatments (T0: 0 ppm, T1: 1 ppm, and T2: 10 ppm) on the growth regulation and physiological parameters of basil and chervil plants under salinity stress conditions (150 mM NaCl). The study explored various growth outcomes and biochemical parameters, including chlorophyll, proteins, soluble sugars, proline, and nitrate. The results indicate that the application of gibberellic acid alleviated the adverse effects of high salinity and resulted in enhanced biomass production. In comparison to the control treatment, foliar surface values for basil and chervil increased by 15% and 35%, respectively, in T2. Moreover, root lengths of basil and chervil reached their highest values in T2, showing a 16% increase for basil and a 33% increase for chervil. Carotenoid levels were positively influenced by GA3 treatments, reaching high concentrations in T2, exceeding T0 levels by 41% for basil and 83% for chervil. Additionally, under T2 treatment, protein and glucose levels increased by factors of 2.7 and 1.7, respectively, in basil plants and by factors of 2.1 and 1.7, respectively, in chervil plants. The application of gibberellic acid led to a 33% reduction in proline content for basil and a 27% reduction for chervil compared to the T0 treatment.

Synergistic mechanism and environmental behavior of tank-mix adjuvants to topramezone and atrazine.

An effective way to reduce herbicide quantity is to use adjuvants in order to optimize the amount of herbicide and improve its control efficiency. In order to screen for efficient herbicide tank-mix adjuvants, improve the control of weeds in maize fields, reduce the amount of effective ingredients, and improve the adsorption and digestion behavior of herbicides in soil, this study evaluated the synergistic effects and soil behavior of four types of tank-mix adjuvants combined with herbicides. Different types of adjuvants can enhance herbicide production. Surface tension was significantly reduced by 13% after the pesticide solution was applied with AgroSpred™ Prime. The contact angle with the foliar surface was significantly reduced and solution wettability improved using Atp Lus 245-LQ-(TH). The permeability of topramezone and atrazine in leaves of Amaranthus retroflexus L. and Digitaria sanguinalis (L.) Scop. was increased by 22-96% after adding either tank-mix adjuvant. The solution drying time and maximum retention on leaves were not affected by the tank-mix adjuvants. Ethyl and methylated vegetable oils can reduce the adsorption of topramezone in the soil, thus reducing its half-life in soil. The tank-mix adjuvants had no significant effect on soil dissipation or adsorption of atrazine. AgroSpred™ Prime and Atp Lus 245-LQ-(TH) have the best synergistic effect on topramezone and atrazine in the control of A. retroflexus L. and D. sanguinalis (L.) Scop. in maize fields.

Substantial contribution of tree canopy nitrifiers to nitrogen fluxes in European forests

Human activities have greatly increased the reactive nitrogen in the biosphere, thus profoundly altering global nitrogen cycling. The large increase in nitrogen deposition over the past few decades has led to eutrophication in natural ecosystems, with negative effects on forest health and biodiversity. Recent studies, however, have reported oligotrophication in forest ecosystems, constraining their capacity as carbon sinks. Here we demonstrate the widespread biological transformation of atmospheric reactive nitrogen in the canopies of European forests by combining nitrogen deposition quantification with measurements of the stable isotopes in nitrate and molecular analyses across ten forests through August–October 2016. We estimate that up to 80% of the nitrate reaching the soil via throughfall was derived from canopy nitrification, equivalent to a flux of up to 5.76 kg N ha−1 yr−1. We also document the presence of autotrophic nitrifiers on foliar surfaces throughout European forests. Canopy nitrification thus consumes deposited ammonium and increases nitrate inputs to the soil. The results of this study highlight widespread canopy nitrification in European forests and its important contribution to forest nitrogen cycling.

The Effect of External Treatment of Arabidopsis thaliana with Plant-Derived Stilbene Compounds on Plant Resistance to Abiotic Stresses.

Stilbenes are a group of plant phenolic secondary metabolites, with trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) being recognized as the most prominent and studied member. Stilbenes have a great potential for use in agriculture and medicine, as they have significant activities against plant pathogens and have valuable beneficial effects on human health. In this study, we analyzed the effects of direct application of stilbenes, stilbene precursor, and stilbene-rich extract solutions to the plant foliar surface for increasing the resistance of Arabidopsis thaliana to various abiotic stresses (heat, cold, drought, and soil salinity). Exogenous treatment of A. thaliana with stilbenes (trans-resveratrol, piceid, and spruce bark extract) and phenolic precursor (p-coumaric acid or CA) during germination resulted in considerable growth retardation of A. thaliana plants: a strong delay in the root and stem length of 1-week-old seedlings (in 1.3-4.5 fold) and rosette diameter of 1-month-old plants (in 1.2-1.8 fold), while the 2-month-old treated plants were not significantly different in size from the control. Plant treatments with stilbenes and CA increased the resistance of A. thaliana to heat and, to a lesser extent, to soil salinity (only t-resveratrol and spruce extract) to drought (only CA), while cold resistance was not affected. Plant treatments with stilbenes and CA resulted in a significant increase in plant resistance and survival rates under heat, with plants showing 1.5-2.3 times higher survival rates compared to untreated plants. Thus, exogenous stilbenes and a CA are able to improve plant survival under certain abiotic stresses via specific activation of the genes involved in the biosynthesis of auxins, gibberellins, abscisic acid, and some stress-related genes. The present work provides new insights into the application of stilbenes to improve plant stress tolerance.

Enhancing the salt stress resistance of seeds and seedlings via a brassinolide sustained release agent system

BackgroundThe growing escalation of soil salinization is tremendously threatening the global food security and the development of sustainable agriculture. To address the worldwide predicament caused by salt stress toward crops, combining nanotechnology with the merits of plant hormone may become an efficient and effective approach.ResultsIn this work, a sustained release agent system (BR@MSN) was developed by loading brassinolide (BR) to mesoporous silica nanoparticles (MSN) to enhance the salt stress resistance of cucumber seeds and seedlings. The obtained BR@MSN agent was about 120 nm. As an endogenous plant hormone, promotion in crop growth was found at low BR concentration. Due to the sustained release property, BR@MSN avoided excessive BR exposure to seeds and seedlings to cause inhibitory effects. After the soil application of BR@MSN, the promotion effect from BR combined with the regulation enhancement from MSN nanocarrier improved the seed germination rate by 11.76% under saline environment. Compared with the same BR concentration (2.0 mg/L), BR@MSN increased the seed germination rate even by 1324.29%. In addition, remarkable wettability on foliar surfaces was found, and the foliar application of BR@MSN significantly enhanced the salt stress resistance of cucumber seedlings by alleviating the accumulation of reactive oxygen species (ROS) and increasing the cell viability along with the improvement in superoxide dismutase (SOD) activity (234.11%), the decrease in malondialdehyde (MDA) content (61.30%), and the increase in chlorophyll content (110.88%).ConclusionsThe newly developed BR@MSN agents could effectively enhance the salt stress resistance of crop seeds and seedlings, and their applications significantly improved the seed germination rate and seedling growth. The remarkable efficacy makes this BR@MSN agent system potential in agricultural field for enhancing the salt stress resistance of crops and facilitating the development of sustainable agriculture.Graphical

Differential response to calcium-labelled (44Ca) uptake and allocation in two peach rootstocks in relation to transpiration under in vitro conditions

Calcium-labelled (44Ca) uptake and transport under in vitro GreenTray® temporary immersion bioreactor conditions have been studied related to aeration conditions. For this aim, Rootpac®-20 (RP-20) and Garnem® (G × N) were selected as two main rootstocks used in peach production. Two transpiration conditions, aerated and unaerated, were established for each plant material. 44Ca location, plant development and foliar stomata surface were measured after the in vitro culture period. The results showed that aeration improved Ca transport within the shoot, but it did not enhance Ca uptake by the roots. Regarding plant material, G × N presented a better Ca uptake capacity and concentration. The findings suggest that Ca uptake in the roots is a precise process that is influenced by transpiration. However, it was observed that transpiration and thus the water flux is not the only force promoting Ca uptake by roots. Furthermore, the transport of Ca to the shoot was primarily determined by transpiration, indicating that water flux plays a crucial role in the aboveground movement of Ca. The study also revealed distinct behaviors in Ca uptake and allocation between the different peach rootstocks, emphasizing the importance of considering these factors in the selection process of rootstocks. These findings contribute to our understanding of the mechanisms involved in Ca uptake and transport in peach rootstocks under in vitro conditions. They provide valuable insights for rootstock selection processes and highlight the need for further research in this area.

Self-assembly of eugenol-loaded particles to regulate the adhesion of carriers on leaves for efficient foliar applications and ecotoxicological safety

Currently, there is a pressing need to develop an agrochemical-loaded system that is both uncomplicated and efficient, thereby enhancing the adhesion of agrochemical to leaf surfaces and optimizing their insecticidal efficacy, while concurrently mitigating environmental risks. The flexible eugenol-loaded particles were synthesized via a one-step polyurethane self-assembly reaction, utilizing polyethylene glycol (PEG) as the soft segment and 4,4-diphenylmethane diisocyanate (MDI) as the hard segment. The increase in the length of the soft segment enhances the flexibility of the particles, thereby improving the contact area and adhesion with the foliar surface. When flexible particles are applied on the foliar surface, they can achieve satisfactory resistance to rainfall erosion. When the PEG molecular weight is 800, the residual concentration of eugenol can still reach 42.11% after 6 washes. The carrier protects the active ingredients and improves the resistance to ultraviolet irradiation. After 5 h of ultraviolet irradiation, the concentration of eugenol remained at 59.03% when PEG with a molecular weight of 200 was employed. Greenhouse experiments showed that the flexible transformation of particles greatly enhanced the application effect of spray on the foliar surface of particles. After undergoing three washes, the mortality of the particles can be enhanced by 5.4–8.4 times compared to that of emulsion concentrate (EC) sample. The enhancement of leaf retention performance reduces environmental risks caused by pesticide loss. Meanwhile, the controlled release of particles also reduces the acute toxicity to zebrafish. The toxicity selection pressure of the EUG@P800-Ps sample is 10.6 times that of the EC sample. In conclusion, the preparation process of the system is simple, and the flexible transformation is an effective strategy to improve the foliar application effect of spray and improve the environmental safety.

Effects of road dust on vegetation composition and surface chemistry of three ombrotrophic peatlands in eastern Canada

Dust deposition can fertilize nutrient-limited peatlands and affect their plant assemblages and ecosystem functions, but the effects of local road dust on peatlands have seldom been studied. Here, we investigate the responses of vegetation composition and surface chemistry (vegetation, surface peat, and groundwater chemistry) at three ombrotrophic peatlands: Rivière-au-Tonnerre (RT), Chemin de l'Anse-de-la-Grande-Pointe (GP), and Kegaska (KEG) in eastern Québec, Canada, to varying levels of road dust deposition with differential chemical composition. At each site, a transect aligned with the dominant wind direction, starting at and perpendicular to the roadside, was sampled at increasing intervals up to 250 m away from the gravel (unpaved) road. We find that the ash content of surface peat is highest closest to the roads at all three sites and decreases exponentially with increasing distance up to 200 m away from the roads. At KEG, with the highest amount of, and the most phosphorus (P) rich, road dust deposition, the ash content is highest among the three sites, decreasing most rapidly with distance away from the road. The stoichiometric mass ratios of carbon (C), nitrogen (N) and P, i.e., C:N, C:P, and N:P, in foliar tissues and surface peat increase significantly with distance away from the road at KEG, and mosses are found to be more responsive in terms of foliar chemistry than shrubs to the road dust deposition. A higher concentration of total dissolved phosphorus at KEG is found closer to the road. At GP, having a moderate amount of road dust deposition, significant increases in C:N, C:P, and N:P ratios with distance are found only in surface peat but not in foliar tissues. Due to the presence of carbonate minerals in the road dust of GP, the calcium (Ca) concentration and pH value of groundwater closer to the road are higher, leading to an obvious loss of vegetation coverage, especially mosses, and a consequent increase in NO3− leaching. In contrast, at RT, having the lowest amount of road dust deposition, only a few clear variation patterns in surface chemistry are found along the sampling transect. Overall, our results suggest that dust from gravel roads can be an important localized source of nutrients for adjacent peatlands and influence their vegetation composition and surface chemistry, depending on the amount of road dust and its chemical composition, especially its contents in Ca and P.

Backyard aerosol pollution monitors: foliar surfaces, dust enrichment, and factors influencing foliar retention.

Air pollution is one of the leading causes of death from noncommunicable diseases globally, and in Arizona, both mining activities and abandoned agriculture can generate erodible dust. This dust is transported via wind and can carry high amounts of toxic pollutants. Industry-adjacent communities, or "fenceline communities," are generally closer to the pollution sources and are disproportionally impacted by pollution, or in this case, dust. The dust transported from the mine settles into nearby rivers, gardens, and homes, and increases the concentrations of elements beyond their naturally occurring amounts (i.e., enriched). This study was built upon previous community science work in which plant leaves were observed to collect similar concentrations to an accepted dust collection method and illustrated promise for their use as low-cost air quality monitors in these communities. This work investigated the concentration of Na, Mg, Al, K, Ca, Mn, Co, Cu, Zn, Mo, and Ba in dust from the leaves of community-collected backyard and garden plants (foliar dust), as well as if certain variables affected collection efficacy. This assessment evaluated (1) foliar concentration versus surface area for 11 elements, (2) enrichment factor (EF) values and ratios, (3) comparisons of foliar, garden, and yard samples to US Geological Survey data, and (4) what variable significantly affected dust collection efficacy. The EF results indicate that many of the samples were enriched (anthropogenically contaminated) and that the foliar samples were generally more contaminated than the yard and garden soil samples. Leaf surface area was the most influential factor for leaf collection efficiency (p < 0.05) compared to plant family or sampling location. Further studies are needed that standardize the plant species and age and include multiple replicates of the same plant species across partnering communities. This study has demonstrated that foliar dust is enriched in the participating partnering communities and that plant leaf samples can serve as backyard aerosol pollution monitors. Therefore, foliar dust is a viable indicator of outdoor settled dust and aerosol contamination and this is an adoptable monitoring technique for "fenceline communities."

Progression toward maximum leaf surface storage during the rainfall interception process

AbstractDuring rainfall events, leaves in the canopy absorb kinetic energy from falling raindrops causing the leaves to vibrate after each individual drop impact. Additionally, intercepted water gradually increases on foliar surfaces adding greater mass exerted on each leaf. This accumulated mass of water increases the leaf inclination angle and may enable the drainage of water from the leaf surface as the water drop retention angle is surpassed. This study explored the dynamic process of leaf vibration and changes in steady‐state leaf inclination angles after raindrop impact for three species (Acer saccharinum, Quercus gambelii, and Ulmus pumila) and with four different drop sizes. An incremental increase in steady‐state leaf inclination angle was measured from processing single frames of videos as each additional raindrop impacted leaf surfaces. In general, larger drops increased leaf inclination angles to a larger degree than the smaller drops. As maximum leaf surface storage or the water drop retention angle was approached, water drained from leaf surface causing an abrupt rebound of the leaf inclination angle. The maximum changes in steady‐state leaf inclination angle before rebound (LIAmax) and the number of drops needed for leaf inclination angle rebound were significantly correlated with the initial leaf inclination angle (LIAi) for experiments with A. saccharinum and U. pumila, but not for the experiments with Q. gambelii. No significant correlations were found between LIAmax and any leaf trait (i.e., leaf area, leaf mass, petiole length, petiole diameter, leaf hydrophobicity, and water drop retention) for A. saccharinum and U. pumila; however, a significant negative correlation was found for Q. gambelii between maximum changes in leaf inclination angle and petiole diameter. Of the leaf characteristics examined, leaf surface storage is most influenced by LIAi before drop impact.

Ecofriendly polysaccharide-based alginate/pluronic F127 semi-IPN hydrogel with magnetic collectability for precise release of pesticides and sustained pest control

Controlled-release systems are crucial for efficient pesticide utilization and environmental protection in agricultural production. The utilization of polysaccharide-based materials derived from biopolymers as carriers for controlling pesticide release holds significant potential. In this work, a reversible near infrared-responsive polysaccharide-based hydrogel (RNPH) was fabricated by employing a semi-interpenetrating polymer network (alginate-FeIII/pluronic F127) as a carrier to encapsulate Fe3O4@polydopamine (FP) and emamectin benzoate (EB)-loaded hollow mesoporous silica. The incorporation of FP into the RNPH introduced a photothermal effect, enabling the precise release of EB through reversible shrinkage of the hydrogel upon NIR irradiation. Additionally, the presence of magnetic Fe3O4 in the system facilitated the rapid removal of remaining RNPH from the environment using a magnet, reducing EB residue. Importantly, RNPH exhibited exceptional controlled-release performance and could be reused for at least 4 cycles. Furthermore, the anti-photolysis ability of EB protected by RNPH was enhanced by 4.8 times compared to EB alone. Moreover, RNPH significantly improved the adhesion of EB to foliar surfaces, thereby reducing the loss of EB while ensuring crop safety. Therefore, the polysaccharide-based hydrogel holds promise as a versatile carrier for the precise release of EB, offering valuable applications in enhancing pesticide bioavailability and promoting environmental safety.

Effects of Foliar and Soil Applications of Silicic Acid (Silicon 0.8%) on the Growth and Yield of Tomato under Greenhouse Conditions

Tomato (Solanum Lycopersicum L.) is an important vegetable crop in Iraq. Experiments have been conducted to compare the effects of foliar and soil surface (drench) applications of silicic acid on tomato under greenhouse conditions. The experiment consisted of treatments with or without silicic acid (AB Yellow) treatments with different concentrations to evaluate the efficacy on growth, yield, and quality parameters of tomato. The results showed that foliar applied and soil drenching of silicic acid in different concentrations (0.5, 1 and 2 ml/L) significantly increased yield and quality attributes compared to control. Silicic acid, applied as foliar spray or as soil drench, as 2 ml/L increased growth and yield significantly.

Photo‐Stimuli Smart Supramolecular Self‐Assembly of Azobenzene/β‐Cyclodextrin Inclusion Complex for Controlling Plant Bacterial Diseases

AbstractControllable and on‐demand delivery of supramolecular systems have received considerable attention in modern agricultural management, especially for managing intractable plant diseases. Here, an intelligent photoresponsive pesticide delivery system is reported based on β‐cyclodextrin (β‐CD) and azobenzene, which overcomes the resistance of phytopathogens caused by the irrational use of conventional pesticides. Antibacterial bioassays illustrated that designed azobenzene derivative 3a possesses the most efficient bioactivity with EC50 values of 0.52–25.31 µg mL−1 toward three typical phytopathogens. Moreover, the assembly of the supramolecular binary complex 3a@β‐CD is successfully elucidated and displays exceptional inhibitory activity on biofilm formation. Of note, this supramolecular binary complex significantly improves the water solubility, foliar surface wettability, and shows marked light‐responsive properties. In vivo anti‐Xoo assays reveal that 3a@β‐CD has excellent control efficiency (protective activity: 51.22%, curative activity: 48.37%) against rice bacterial blight pathogens, and their control efficiency can be elevated to values of 55.84% (protective activity) and 52.05% (curative activity) by UV–vis exposure. In addition, the 3a@β‐CD are non‐toxic toward various non‐target organisms. This study therefore offers new insights into the potential of host‐guest complexes as a feasible pesticide discovery strategy characterized by a safe, biocompatible, light‐responsive release, and antibiofilm properties for overcoming intractable plant bacterial diseases.