Fine roots regulate plant water uptake, but the dynamic cell-level hydraulic behaviour of these organs remains poorly understood, particularly at the onset of drought. We investigated changes in fine root (<2 mm diameter) shrinkage, turgor loss, cell layer viability and uptake during dehydration and rehydration in soybean (Glycine max)to identify critical physiological thresholds of water potentials experienced by plants exposed to experimental drought. Fine root diameter shrank by over 50% at the completion of drying, with 55.36% of this relative shrinkage occurring by -0.25 MPa, and most of that water volume loss was attributed to epidermal and cortex cells. Epidermal cells lost turgor at -0.5 MPa and cortex cells reached mortality by -1.0 MPa, prior to xylem embolism onset. Cells within the stele remained viable after cortex and epidermal mortality until -1.75 MPa, coinciding with the 50% loss of xylem conductivity through embolism (whole-plant P50). Drought recovery experiments revealed that cortical and epidermal cell mortality slowed but did not prevent rehydration of those same cell layers, or whole plant rehydration, prior to embolism. The rapid, dynamic changes in cortical and epidermal cells during the earliest stages of drought exposure, and subsequent recovery, likely act to physically decouple fine roots from the surrounding soil to limit plant dehydration; an effect likely accelerated by bare-root lab drying conditions. Movement of water through these dead cell layers allows rehydration of living stele tissue prior to embolism, supporting root growth and recovery post-drought.

Water availability strongly influences plant survival and distribution in the Cerrado, but many species co-occur in contrasting phytophysiognomies (Gallery vs. Seasonal Semideciduous Forest). This study aimed to assess whether individuals of the same species, growing in environments with contrasting water availability, adopt similar hydraulic strategies and how these strategies influence drought tolerance and growth. Five co-occurring tree species were sampled in adjacent Cerrado fragments (Gallery and Seasonal Semideciduous Forest). Traits related to growth, water storage, water loss, and drought tolerance were measured, and comparative analyses were conducted to test for convergence or divergence of functional strategies across species and habitats. Each phytophysiognomy has a specific and consistent group of physiological characteristics but, within each phytophysiognomy, the characteristics were similar between species. Despite hotter and drier conditions, Seasonal Semideciduous Forest species maintained water potential similar to that of Gallery Forest species due to drought-tolerance mechanisms. In the Seasonal Semideciduous Forest, higher carbon assimilation enabled the development of more drought-tolerant leaves, with changes in total leaf area, residual water leaks, xylem tolerance to embolism, specific leaf area and water potential at the turgor loss point. This plasticity enables the occupation of contrasting habitats, enhancing ecosystem resilience to climate variability. In the Seasonal Semideciduous Forest, hydraulic safety was associated with species ecological dominance. Habitat was the strongest predictor of trait variation, with microclimatic gradients shaping distinct carbon-use patterns and drought-response strategies in Cerrado plants. Regardless of the strategy adopted, species in both areas operated with a broad hydraulic safety margin, indicating high resilience. This may lead to a homogenization of the Cerrado Domain under climate change, as species with lower plasticity may be unable to compete with those that occur across different phytophysiognomies.

In recent decades, heatwaves and droughts have accelerated tree mortality largely via xylem dysfunction and its downstream effects. Whether a tree succumbs to or recovers from drought depends in large part on viable cambial tissue, which is needed to produce new xylem and phloem in subsequent years. We conducted a drought-stress and rewatering experiment on saplings to examine how the vascular cambium responds to water deficit. Cambial viability was assessed using the Neutral Red stain, in addition to measurements of hydraulic function. Cambial viability was significantly reduced when saplings were exposed to moderate water stress, but adding water rehydrated the saplings and the cambium also recovered. By contrast, neither hydraulic nor cambial function recovered in saplings that were exposed to severely low water potentials followed by rewatering. Eventually, the leaves of the severely stressed saplings turned brown and the plants died. Our results suggest that a viable vascular cambium relies on functional xylem. The Neutral Red assay can assess cambial viability and potentially serve as a proxy for hydraulic function in ailing trees recently impacted by environmental stress.

This study investigated the relationship between Subsoil Geological Structure (SSGS) and the yield, berry composition, and wine attributes of Merlot grapevines in a mountainous region. The research found significant differences in vine physiology, yield, and berry chemistry of grapevines between five adjacent rows, which corresponded with the underlying SSGS. The middle row, planted over filling material and a karst layer, had the highest yield (1.96 kg·vine−1), consistent with better water availability, but produced berries and wine with the lowest concentrations of anthocyanins, phenolics, and soluble solids, resulting in the lowest wine quality score (82.33 points). In contrast, the northernmost row planted over bedrock had the lowest yield (0.12 kg·vine−1), consistent with limited water availability, but produced highly concentrated berries, though extreme stress compromised overall wine balance. The southern row, positioned over filling material on bedrock with moderate water stress (stem water potential −1.4 MPa), achieved an optimal balance between yield and quality, producing wine with the highest sensory score (88.78 points) and favorable chemical composition. Geophysical methods, including electric resistivity tomography (ERT) and ground-penetrating radar (GPR), identified the subsurface structure, revealing the karst layer beneath high-yielding rows and consolidated bedrock beneath severely stressed rows. Chemical analyses of berries and wine confirmed the dilution effect of higher water availability on quality-determining compounds, providing mechanistic evidence linking SSGS to wine quality. This study demonstrates the utility of integrating geophysical, physiological, and enological approaches for understanding terroir effects and optimizing vineyard management in complex geological settings.

Seed imbibition and germination under water stress conditions are critical determinants of successful crop establishment; therefore, understanding imbibition responses under osmotic stress is essential for improving seed quality assessment and management strategies for crop production under suboptimal water availability. This study aimed to analyze the effect of reduced water potential on the imbibition curve and triphasic pattern of seeds in several Solanaceae species. The study used seeds from three Solanaceae crops—chili (Capsicum annuum L., varieties Simpatik and Sempurna), tomato (Solanum lycopersicum L., varieties Niki and Rempai), and eggplant (Solanum melongena L., varieties Tangguh and Provita). The seeds were subjected to various levels of osmotic stress using polyethylene glycol (PEG 6000) to simulate water potentials of 0.00, −0.30, −1.90, and −4.10 MPa. Lower water potential in the growing medium reduced the seed’s ability to absorb the water. The triphasic pattern consistently appeared only in chili seeds, whereas in tomatoes and eggplants, it varied across varieties and water potential conditions. Lower water potential delayed the end of Phase I and prolonged the duration of Phase II. These findings confirm that the standard imbibition pattern cannot be generalized to all seeds, and therefore, the imbibition response is specific to seed type, variety, and germination environment.

In savanna ecosystems, water availability and fire are interconnected, shaping plant structure and diversity. In Cerrado, factors such as water seasonality and fire-related cues (e.g., smoke) interact to influence recruitment. This study investigated the germinative and post-germinative responses of Cerrado ground-layer species to a gradient of water potential reduction, both independently and in combination with smoke water (SW). It assessed the effects of smoke and water deficit on treatment (WDT) and post-water deficit recovery (WDR), exploring the potential protective role of smoke under these conditions. Different concentrations of polyethylene glycol 6000, both alone and in combination with 10 and 25 mL L-1 of SW, were used to assess the germination and seedling growth responses of 15 Cerrado ground-layer species at 25°C. After WDT, species were subjected to the WDR (using only deionized water) to evaluate recovery capacity. Effect sizes were used to evaluate species' responses to the treatments and whether these responses were associated with growth forms (i.e., shrubs and herbs). Reduced water potential was the primary factor negatively impacting germination and post-germination responses. While species-specific, SW had a protective effect on germination and seedling growth under moderate water deficit. Tolerance to water deficit was more evident in shrub species, whereas positive responses to SW were more common in herbaceous species. During WDR, most species either recovered from WDT and germinated or maintained seed viability. Herbaceous species showed a stronger recovery, with germination reaching control levels. Both water potential reduction and SW influence the germination and seedlings' growth of Cerrado ground-layer species and growth forms. Smoke can alleviate stress induced by water deficit, with species showing tolerance without loss of seed viability, suspending germination under stress but retaining their ability to recover.

Synergistically enhancing both photosynthetic rate (A) and intrinsic water use efficiency (iWUE) in rice remains a major challenge for achieving high productivity in the future. In this study, 37 cultivated rice (Oryza sativa) varieties with significant variation in stomatal morphological traits were selected for pot experiments. Among these, the two highest and two lowest stomatal density varieties were further subjected to drought treatments. Under well-watered conditions, stomatal density was identified as a key factor coordinating stomatal conductance (gs) and mesophyll conductance (gm) among rice varieties by influencing mesophyll cell arrangement through stomatal development. Although increased stomatal density enhanced A, it did not synergistically improve iWUE. Under water stress, however, stomatal aperture decreased rapidly as drought intensified, gradually diminishing the positive effect of high stomatal density on gs until it disappeared. Notably, varieties with high stomatal density maintained higher gm than those with low stomatal density across the entire range of leaf water potentials measured, enabling simultaneous enhancement of both A and iWUE under drought conditions. Our study demonstrates that high stomatal density can synergistically enhance both AandiWUE under drought conditions, underscoring its potential utility in breeding drought-tolerant rice varieties.

Curcuma is a traditional Chinese medicine that has been utilized for centuries in the treatment of various diseases. Terpenoids, particularly monoterpenes and sesquiterpenes, constitute the primary bioactive components of the essential oil derived from Curcuma species. Among these, curdione-one of the key active constituents-has been identified in 25 Curcuma species, with the highest concentration reported in the rhizome essential oil of Curcuma trichosantha Gagnep. Curdione can also be synthesized through chemical methods, and its regio- and stereo-selectivity can be further optimized via chemo-bio transformations. This compound demonstrates significant therapeutic potential, including anticancer, anti-thrombotic, anti-inflammatory, anti-viral, anti-fungal, anti-diabetic, and multi-organ protective properties. Despite these promising biological activities, its clinical application is hindered by poor water solubility and potential toxicity. This review summarizes current knowledge on the natural sources, chemical synthesis, chemo-bio transformations, metabolism, pharmacokinetics, pharmacological effects, potential toxicities, and molecular mechanisms of curdione. Furthermore, perspectives on future drug development are discussed with the aim of promoting the clinical translation of this promising natural compound.

Plant leaf drought tolerance is regulated by the coordinated effects of water transport efficiency, transpirational water loss, and hydraulic safety. Although cotton is considered drought-tolerant, the mechanisms that coordinate water transport and gas exchange to confer drought tolerance remain incompletely understood. In this study, four soil moisture gradients were established under field conditions and maintained consistently throughout the growing season. The relationships among leaf turgor loss point (Ψtlp), gas exchange, and hydraulic traits were examined in two cotton cultivars at the peak flowering stage. With increasing drought treatments, Ψtlp, stomatal aperture ratio (gratio), leaf hydraulic conductance (Kleaf), leaf hydraulic conductance inside the xylem (Kx) and leaf hydraulic conductance outside the xylem (Kox) declined significantly, with Kx showing the greatest reduction. Both Kx and gratio were strongly positively correlated with Ψtlp. Anatomically, vein density (Dv) and vessel number (Np) increased, whereas xylem vessel area (Ap) decreased. The reduction in Ap was the primary structural factor driving the decline in Kx and contributing to lower Ψtlp. We conclude that cotton enhances drought tolerance through a coordinated hydraulic and osmotic strategy, by modifying xylem anatomy (reducing Ap) to downregulate Kx and by adjusting osmotically to depress Ψtlp. The synergistic reduction in Kx and gratio slows the decline in leaf water potential, thereby delaying Ψtlp and enhancing leaf hydraulic safety during drought. This integration optimizes stomatal regulation and water transport while ensuring hydraulic safety. The findings provide a key theoretical basis and potential breeding targets for the targeted improvement of drought tolerance and water use efficiency in cotton.

Alfalfa (Medicago sativa L.) is an important perennial leguminous crop whose growth and yield are frequently limited by drought stress because the main planting areas are concentrated in arid and semi-arid regions. Plant growth-promoting rhizobacteria (PGPR) are crucial for enhancing plant stress resistance and constitute an attractive supplementary strategy for alfalfa production, but this has mainly been based on the use of single-strain inoculants in rhizobia. Here, we designed a microbial consortium to alleviate drought stress in alfalfa. Seven PGPR strains isolated from the rhizosphere and five rhizobial strains with in vitro growth-promoting properties obtained from alfalfa nodules were chosen. Based on a comprehensive evaluation of drought tolerance, growth-promoting traits, and metabolite-feeding experiments, we selected Sinorhizobium meliloti GAU-93 and Bacillus mycoides Y1 to construct a drought-resistant microbial consortium (DR-MC). A pot experiment indicated that inoculation with the microbial consortium enhanced drought resistance by increasing osmotic adjustment substance levels and reducing malondialdehyde content, promoting alfalfa growth. Separately, GAU-93 promoted aboveground growth by increasing photosynthetic pigment content under different water potential conditions, whereas Y1 enhanced root development and protected the plant from drought-induced oxidative damage. The DR-MC selected in this study is a valuable tool for further development to improve drought resistance in alfalfa.

Groundwater is the most utilized source of domestic potable water in Damaturu metropolis of Yobe State, Nigeria as a result of the paucity of surface water resources, which, due to climate variability, population increase and higher anthropogenic activities, are depleting over time. This study, therefore, assessed the groundwater potential of Obasanjo Quarters, Damaturu for zoning appropriate areas for sustainable borehole siting. A total of Seven (7) Vertical Electrical Sounding (VES) lines, performed using the Schlumberger array, were used to characterize subsurface geoelectric layers in the study area and to delineate aquiferous targets. Interpreted resistivity data shows several geoelectric layers, mainly inter-bedded sands, clays, silt and sandy clay lenses characteristic of the Chad Formation with unconfined and confined aquifer conditions across many sounding points. This is supported by the curve types of K, KH and mainly A-types generated from the sounding data, which show good hydrogeological conditions across the study area. However, several VES points had low resistivity layer at depth of ~80 m to ~350 m and interpreted as saturated layers with high groundwater potential and suggested drilling depth of 90 ± 5 m to 350 ± 5 m. The study therefore confirms that Obasanjo Quarters has exploitable groundwater bearing formations, and therefore, can support domestic and municipal water supply. This result provides basis for informed drilling of boreholes and for sustainable groundwater management in Damaturu metropolis, where water table is on the decline and reported cases of borehole failures are rife in recent times.

This study examines the application of mining effluents as feed solutions in a bench scale pressure retarded osmosis (PRO) system for energy generation and the prospect of water recycling or safe discharge to the environment. Effluents were characterized and pretreated by ultrafiltration (UF) and nanofiltration (NF) prior to PRO. The PRO process was then conducted over 6 h in a cross flow flat plate cell with an effective membrane area of 34 cm2, a hydraulic pressure of 12.4 bar and a 3M ammonium carbonate (NH4)2CO3 as draw solution. Effluent 1 contained ions such as Cl− (539 mg/L), NO3− (585 mg/L), SO42− (3000 mg/L), Na+ (560 mg/L), and Mg2+ (656 mg/L), with a total dissolved solids (TDS) concentration of 5400 mg/L, chemical oxygen demand (COD) of 136 mg/L, total organic carbon (TOC) concentration of 3.5 mg/L, and acidic pH of 3.8, while effluent 2 was highly dominated by Cl− (32,100 mg/L), NO3− (9720 mg/L), SO42− (6512 mg/L), Na+ (14,306 mg/L), and Mg2+ (5336 mg/L), had a TDS concentration of 73,315 mg/L, COD of 8100 mg/L, TOC concentration of 10.2 mg/L, and pH of 7.4. These physiochemical properties indicated a significant potential of fouling and scaling which necessitated the appropriate pretreatments. It was shown that integrating UF and NF pretreatments was highly effective in refining the quality of effluents with a significant removal efficiency of above 90% for ions and heavy metals by NF, led to fouling mitigation, higher and more stable power density as well as potential water reuse or safe environmental discharge. The achieved water fluxes and power densities were 54 L/m2h and 18.6 W/m2, for effluent 1, and 38 L/m2h and 13 W/m2, for effluent 2, respectively. The outcome of this study is applicable for the mining sector especially in remote areas with the potential for water and energy recoveries to contribute to more sustainable mining operations.

Understanding hydrological, agricultural, and environmental processes in soils relies on accurately measuring volumetric water content (θ), matric potential (h), and hydraulic conductivity (K). These parameters are fundamental for quantifying plant-available water, optimizing irrigation scheduling in precision agriculture, modeling watershed responses, and studying the impacts of climate change in complex ecosystems. Among these parameters, θ is truly indispensable, as it represents the primary indicator of the water status of soils and a prerequisite for interpreting the other hydraulic variables. In recent years, capacitive sensors have become one of the most widely adopted technologies for θ estimation, owing to their favorable balance between accuracy, robustness, and affordability. These sensors infer soil moisture by measuring dielectric permittivity of soils, which is strongly governed by water content, making them particularly suitable for distributed monitoring and IoT-based environmental applications. The present study aimed to develop a low-cost capacitive sensor for θ estimation. This sensor can be made using 3D printing technology combined with conductive, nickel-based paint, which (once applied on the 3D-printed guides) forms the capacitive electrode. The capacitive component operates at an operational frequency of 60 MHz. The system was subjected to a rigorous testing protocol, including calibration and validation phases under laboratory conditions using three soils of different textures. Its performance was specifically compared with the time-domain reflectometry (TDR) technique, which is widely recognized in Soil Physics and Soil Hydrology as the reference method for θ estimation due to its reliability and accuracy. These tests confirmed the effective performance of the proposed sensor, which overall exhibited good reliability within the selected validation range, corresponding to a θ range of 0 to 0.40 cm3/cm3.

Abstract. Consequences of climate change are likely to pose severe challenges on agriculture in Southern Africa. Agroforestry systems (AFSs) can potentially alleviate some of the adverse effects and offer adaptation solutions to a sustainable land use. Positive effects of AFSs may include increasing soil carbon (C) and nitrogen concentrations, sustaining favourable nutrient cycling, protection against erosion and increased carbon sequestration. The influence of the AFS tree component on the soil water storage and thus water availability for the crops, however, is still relatively unknown. In this study we assessed the influence of Gliricidia sepium-maize intercropping on carbon cycling and water fluxes compared to maize as a sole crop at two well-established long-term experiments in central and southern Malawi, run by the World Agroforestry (ICRAF). Utilizing the field experiments of different durations (&gt;10 and &gt;30 years) at the two sites provided information regarding soil-specific impacts of gliricidia on water dynamics. We examined soil C contents and density fractionation as proxy for organic matter stability, soil physical and soil hydrological characteristics. We also monitored soil moisture and matric potential in different depths, determined retention curves on samples in the lab and from field data and analysed soil moisture responses to rainfall events to assess the influence of the AFS on water fluxes. Our results show a clear increase in C contents and stability as a result of the gliricidia impact compared to the control at the site with the generally lower baseline C contents. At this site, the treatment effect was not visible in soil physical characteristics such as porosity and bulk density, but in saturated hydraulic conductivity, which is rather a structural soil property. The soil water dynamics were influenced by several additional factors such as soil texture and interception. The gliricidia treatment showed greater soil water storage capacities and retained overall more water, while generally none of the plots neither control nor treatment were under severe water stress during the observation period. We also noticed a protective effect against soil drying below the topsoil potentially by more immediate/macropore infiltration into the subsoil under gliricidia. We conclude that, from a methodological point of view, assessing the effects on water fluxes requires respective field measurements as they cannot be deduced from soil physical characteristics directly. Overall, the AFS treatment of adding gliricidia into maize cultivation can have a considerable effect on nutrient and water dynamics in the system, however, this effect is also dependent on initial site conditions. A sensible AFS implementation can not only support carbon accumulation and stabilization but also increase the efficient use of available water, thus supporting different aspects towards sustainable agriculture in Malawi.

This study calculates the water environmental capacity and pollution reduction potential in the Nanyi Lake Basin. Water quality status was analyzed using the single-factor index method with monitoring data from 2021 to 2023. Pollutant loads and the contribution of point and non-point sources were quantified using the emission factor method. The water environmental capacity was determined via a one-dimensional model and the control section compliance method. Results show that key pollutants in descending order of severity are total nitrogen (TN), chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), and total phosphorus (TP). The annual pollutant loads entering the river are 8078.19 t COD, 572.14 t NH₃-N, 80.93 t TP, and 844.02 t TN. The calculated environmental capacities for COD are 7914.13 t/a (1D model) and 8186.36 t/a (compliance method); for NH₃-N, 708.26 t/a and 718.39 t/a; and for TP, 169.96 t/a and 170.93 t/a. TN capacity is negative (-263.16 t/a and -251.32 t/a), indicating severe overload. Correlation analysis identifies pH and conductivity as primary influencing factors. Targeted reduction measures are proposed: upgrading urban sewage plants for enhanced nitrogen/organic removal, promoting precision agriculture, and constructing riparian buffers. This study provides empirical support for managing the Nanyi Lake Basin and a reference for similar regions.

Hydraulic redistribution (HR) in plants facilitates bidirectional water transport through the vascular system in response to soil water potential gradients, with implications for ecological facilitation. This study aimed to evaluate the efficacy and results obtained with high-precision weighing lysimeters in detecting HR in olive (Olea europaea L.) using a split-root experimental setup with potted trees. Sixteen pots, each containing half of a plant’s root system, were independently monitored for mass changes to quantify HR between irrigated and water-stressed compartments. The independent weighing of each pair of linked pots was a challenge, but the purpose-built precision lysimeter array effectively isolated weights despite mechanical connections between pot pairs. Results demonstrated measurable water redistribution via roots from irrigated to dry pots, with mass transfer from the irrigated side to the non-irrigated side of the plants, between 10 and 70 g. After irrigation, non-irrigated pots received by HR on average between 3 and 12% of the irrigation water applied in irrigated pots. This furthermore highlighted the potential of the lysimeters for precise quantification of plant-mediated water dynamics. It was observed that HR intensity peaked shortly after irrigation, some hours to one day, and diminished over time, with higher intensity during nocturnal periods or cloudy humid daily conditions of negligible or null evapotranspiration. These findings confirm previous observations with reverse sap flow sensors, now with a different experimental approach, which appears precise but only possible for potted plants, allowing further understanding of HR.

Dehydration tolerance and embolism resistance contribute to plant drought survival, but their limits and combinations in perennial grasses remain unexplored. We investigated four grasses (Stipa species and Dactylis subspecies) from Mediterranean sites prone to intense summer drought. Plant tolerance to soil water deficit and tissue dehydration, embolism resistance (P50), and water-soluble carbohydrates (WSCs) were measured under severe drought. Dactylis were more dehydration tolerant, reaching 50% survival at a lower soil water potential (-6.07 MPa) than Stipa (-2.64 MPa), and at a lower leaf base water content (32.8%) than Stipa (50.0%). Dactylis accumulated higher WSCs in leaf bases [479 mg g-1 dry mass (DM), high fructan concentration] than Stipa (17 mg g-1 DM, high sucrose concentration). WSCs contributed 47% (Dactylis) and 29% (Stipa) to osmotic adjustment. However, Stipa had higher embolism resistance (P50= -8.7 MPa) than Dactylis (-2.9 MPa). Plants from the most arid sites had the highest dehydration tolerance, while embolism resistance was uncorrelated with aridity of the sites of origin. We found the highest embolism resistance and dehydration tolerance reported for herbaceous species. We showed that semi-arid grasses combine contrasting strategies to survive drought. Assessing these strategy combinations is crucial to predicting plant resilience under climate change.

The peanut market in the United States is expected to reach $81 billion dollars in 2025 and the state of Georgia is the main producer. Frequent contamination of peanuts with aflatoxins due to pre and postharvest fungal infection, mainly with Aspergillus flavus, results in up to 30% rejection of shelled runner peanuts. Most studies to mitigate aflatoxins have been focused on peanut varieties and plant responses to environmental stress such as drought and temperature. Despite A. flavus being present in all USA peanut growing soils, information on management of A. flavus populations in soil is scarce. In this study, we designed and implemented a controlled environment system to assess soil water potential (SWP) and soil amendment with antagonistic Bacillus subtilis for monitoring A. flavus populations in soil over time. We found that saturated soil (0 kPa) conditions led to decreased A. flavus titers compared to dryer conditions (30 – 1000) kPa; whereas soil amendment with B. subtilis did not significantly affect A. flavus counts. This method will facilitate further research into strategies to reduce aflatoxigenic Aspergilli in soil and potentially minimize pre-harvest aflatoxin accumulation.

Phytophthora root rot (PRR), caused by Phytophthora cinnamomi, is a major production challenge for avocado growers worldwide. PRR management includes cultural practices, the use of resistant rootstocks, and fungicide applications, however, the recent emergence of more virulent and potassium phosphite-resistant pathogen populations has reduced the effectiveness of these management practices. We evaluated the efficacy of Oomycota fungicides to control PRR in five unreleased experimental rootstocks developed by the University of California, Riverside (UCR) and two commercial rootstocks grafted with 'Hass' under greenhouse conditions. All rootstocks were inoculated with P. cinnamomi and treated with either one of six fungicides representing different modes of action to assess PRR management by evaluating PRR incidence, pathogen propagules in soil (ppg), root health, and stem water potential (SWP). All fungicides reduced PRR incidence and pathogen ppg values ranging from 2.1 to 12.3 % and 0.8 to 2.7 ppg, respectively, compared with the untreated control values (36.2% and 11.8 ppg). Potassium phosphite treatments were only effective when using the most resistant rootstocks. Oxathiapiprolin was the best treatment followed by mefenoxam, fluopicolide, ethaboxam, and mandipropamid. The five UCR experimental rootstocks exhibited significantly less PRR incidence (1.8 to 7.4 %) and P. cinnamomi ppg (0.7 to 2.5 ppg) than the susceptible control (28.2% and 8.9 ppg). Improved PRR management was achieved by combining the most resistant rootstock with fungicide treatments, indicating the cumulative effect of rootstock resistance and fungicide treatment. These results support the commercial release of these UCR experimental rootstocks and registration of new Oomycota fungicides to control avocado PRR.

ABSTRACT In-situ observations provide accurate data on irrigation water use, but their spatiotemporal coverage is limited. This study employed a remote-sensing and machine-learning framework, combined with extensive field data on cropping patterns, to assess water stress and to highlight fields where irrigation water use could be reduced. To this end, actual evapotranspiration (ETa) and its uncertainty were computed from 30-m Landsat imagery using the METRIC method. Additionally, 10-m resolution multi-crop maps were extracted from Sentinel-1 and Sentinel-2 imagery by applying a random forest classifier at different intra-annual periods, based on the crop calendar. Results from the Lake Urmia Basin in northwest Iran demonstrated high crop classification accuracy of 83% to 91% across classification periods. Comparing farm-scale ETa against crop evapotranspiration revealed notable spatiotemporal patterns of water stress during crop development and mid-season, whereas high potential for water savings was observed during the initial and late growth stages.