Search Results (68)

Efficient irrigation management is essential for optimizing yield and quality in specialty crops like hot peppers (Capsicum chinense), particularly under controlled greenhouse environments. This study employed a novel sensor-based system integrating soil moisture and sap flux monitoring to evaluate water use dynamics in Capsicum chinense, a species for which such applications have not been widely reported. Three cultivars—Habanero, Helios, and Lantern—were grown under three volumetric soil moisture contents: low (15%), medium (18%), and high (21%). Water uptake was measured at leaf (transpiration, stomatal conductance) and plant levels (sap flux via heat balance sensors). Photosynthesis, fruit yield, and capsaicinoid concentrations were assessed. Compared to high irrigation, medium and low irrigation increased photosynthesis by 16.6% and 22.2%, respectively, whereas high irrigation favored greater sap flux and vegetative growth. Helios exhibited an approximately 8.5% higher sap flux as compared to Habanero and about 10% higher as compared to Lantern. Helios produced over 30% higher fruits than Habanero and Lantern under high irrigation. Habanero recorded the highest pungency, with a capsaicinoid level of 187,292 SHU—exceeding Lantern and Helios by 56% and 76%, respectively. Similarly, nordihydrocapsaicin and dihydrocapsaicin accumulation were more cultivar-dependent than irrigation-dependent. No significant interaction between cultivar and irrigation was observed, indicating genotype-driven water use strategies. Our study contributes to precision horticulture by integrating soil moisture and sap flux sensors to reveal cultivar-specific water use strategies in Capsicum chinense, thereby demonstrating the potential of an integrated sensor-based irrigation system for efficient irrigation management under increasing water scarcity in protected environments. As a preliminary greenhouse study aimed at maintaining consistent irrigation throughout the growing season across three volumetric soil moisture levels, these findings provide a foundation for subsequent validation and exploration under diverse soil moisture conditions including variations in stress duration, stress frequency, and stress application at different phenological stages. Full article

In this study, we present analysis of TESS photometry, spectral energy distribution (SED), high-resolution spectroscopy, and spot modeling of the ${\alpha }^2$ CVn-type star AL Col (HD 46462). The primary objective is to determine its fundamental physical parameters and investigate its surface activity characteristics. Using TESS short-cadence (120 s) SAP flux, we identified a rotational frequency of 0.09655 ${\mathrm{d}}^{-1}$ ($P_{\mathrm{rot}}=10.35733$ d). Wavelet analysis reveals that while the amplitudes of the harmonic components vary over time, the strength of the primary rotational frequency remains stable. A SED analysis of multi-band photometric data yields an effective temperature ($T_{\mathrm{eff}}$) of 11,750 K. High-resolution spectroscopic observations covering wavelengthrange 4500–7000 Å provide refined estimates of $T_{\mathrm{eff}}$ = 13,814 ± 400 K, $logg$ = 4.09 ± 0.08 dex, and $\upsilon sini$ = 16 ± 1 km s⁻¹. Abundance analysis shows solar-like composition of O ii, Mg ii, S ii, and Ca ii, while helium is under-abundant by 0.62 dex. Rare earth elements (REEs) exhibit over-abundances of up to 5.2 dex, classifying the star as an Ap/Bp-type star. AL Col has a radius of $R=3.74\pm 0.48{\mathrm{R}}_{\odot }$, with its H–R diagram position estimating a mass of $M=4.2\pm 0.2{\mathrm{M}}_{\odot }$ and an age of $0.12\pm 0.01$ Gyr, indicating that the star has slightly evolved from the main sequence. The TESS light curves were modeled using a three-evolving-spot configuration, suggesting the presence of differential rotation. This star is a promising candidate for future investigations of magnetic field diagnostics and the vertical stratification of chemical elements in its atmosphere. Full article

Adipose tissue macrophages (ATMs) play important roles in the progression of obesity-related severe acute pancreatitis (SAP). This study aimed to investigate the alterations of autophagic flux within ATMs, as well as the possible regulatory mechanisms. Obese mice were induced via high-fat diets. SAP was triggered using caerulein and lipopolysaccharide. Inflammatory injuries within pancreatic and adipose tissue were assessed. Autophagic flux, along with the expression of autophagosome-located soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, were examined in ATMs. RNA-sequencing was performed to identify the possible regulatory factor, which was further validated. The results showed that obesity exacerbated inflammatory injuries. ATMs in obesity-related SAP exhibited impaired autophagic flux characterized by reduced autophagosome–lysosome fusion. Expression of autophagosome-located SNARE proteins decreased in ATMs. RNA-sequencing identified Forkhead box as the differentially expressed transcription factor associated with autophagy. The expression and transcriptional activity of Forkhead box O1 (FoxO1) decreased. The inhibition of FoxO1 exacerbated SNARE proteins’ suppression and autophagic flux impairment, while the activation of FoxO1 showed the opposite effect. In conclusion, obesity-induced impaired autophagic flux and autophagosome–lysosome fusion in ATMs are potentially regulated via autophagosome-located SNARE proteins and the transcription factor FoxO1. The impaired autophagic flux in ATMs aggravated inflammatory injuries of obesity-related SAP. Full article

Implied by the terminologies “Harang Reversal” and “Harang Discontinuity”, there are two significant features of the Harang region: (i) the reversal of auroral electrojets along with the underlying plasma convection flow and electric (E) fields, and (ii) the discontinuity between the electrojets/convection flows/E-fields. Even the earliest studies reported the discontinuity observed in the meridional E-field. Conversely, some of the previous studies state that convection flow and E-field reversals do not involve any physical discontinuity. We investigate these two features (i–ii) observed in five topside-ionosphere Harang scenarios. Each scenario occurred during a sequence of events that led to the onset of the substorm expansion phase, when the Harang region was newly formed. Our results show (1) the newly formed Harang region between the dusk and dawn convection cells, where one convection cell wraps around the other, (2) the zonal drift- and E-field reversals, (3) the discontinuity between the dusk and dawn convection flows and also between the reversing E-field components, and (4) the Earthward electromagnetic energy deposition locally minimizing or diminishing within the discontinuity and peaking within the reversing zonal drift and E-fields. Thus, the observed convection flow and E-field reversals involved the development of discontinuity. Full article

Since its first detection in 2013, Xylella fastidiosa subsp. pauca (Xfp) has caused a devastating Olive Quick Decline Syndrome (OQDS) outbreak in Southern Italy. Effective disease surveillance and treatment strategies are urgently needed to mitigate its impact. This study investigates the short-term (1.5 years) effects of thymol-based treatments on infected olive trees of the susceptible cultivar Cellina di Nardò in two orchards in Salento, Apulia region. Twenty trees per trial received a 3% thymol solution either alone or encapsulated in a cellulose nanoparticle carrier. Over two years, sap flux density and canopy-transmitted solar radiation were monitored using TreeTalker sensors, and spectral greenness indices were calculated. Xfp cell concentrations in plant tissues were quantified via qPCR. Neither thymol treatment halted disease progression nor significantly reduced bacterial load, though the Xfp cell concentration reduction increased over time in the preventive trial. Symptomatic trees exhibited increased sap flux density, though the treatment mitigated this effect in the curative trial. Greenness indices remained lower in infected trees, but the response to symptom severity was delayed. These findings underscore the need for longer-term studies, investigation of synergistic effects with other phytocompounds, and integration of real-time sensor data into adaptive disease management protocols. Full article

Recent changes in rainfall patterns driven by climate change, including localized heavy rainfall, droughts, and prolonged rainy seasons, have significantly impacted grapevine growth and quality. An analysis of rainfall patterns in South Korea from 1995 to 2024 revealed that 54.5–58.0% of the annual average precipitation of 1357 mm occurs during the fruit enlargement period from June to August, at an average of seven consecutive days of rainfall, indicating a heightened potential for exposure to increased soil moisture stress for seven days annually. This study evaluated the physiological responses of grapevine cultivars ‘Campbell Early’ and ‘Jinok’ under flooding and excessive soil moisture conditions over a seven-day period. Both cultivars exhibited reductions in leaf (LWP) and stem (SWP) water potential, cumulative sap flow in the xylem (CSF), and photosynthetic rate (Pr) under flooding or excessive soil moisture conditions. At the same time, an increase was observed in the crop water stress index (CWSI) and relative leaf electrolyte leakage (REL). Several investigated parameters indicated impaired water uptake and transport under soil moisture stress conditions. Correlation analysis revealed that soil moisture was negatively correlated with the Pr and CSF, while it was positively correlated with LWP, SWP, REL, and CWSI. Our findings provide critical insights into the physiological responses of grapevines to rainfall variability and offer valuable guidance for future research in this field. Full article

Scrub mangrove forests, dominated by Rhizophora mangle L., are characterized by high porewater salinity, which might compromise individual sap flow rates (SF) due to seasonal and diurnal microenvironmental variations. We tested the functional, anatomical, and SF responses of 12 individuals to microenvironmental variables such as solar radiation, photosynthetic photon flux, wind speed, evaporative demand, and porewater salinity, measured using an in situ weather station. Measurements were made in the dry and rainy seasons in the Yucatan Peninsula, using Granier heat dissipation sensors, installed on tree branches. During the rainy season, SF was twice as high as that during the dry season (0.22 ± 0.00 L h⁻¹ and 0.11 ± 0.00 L h⁻¹, respectively), despite lower evaporative demand. In both seasons, negative relationships between SF with vapor pressure deficit (VPD; dry τ = −0.54; rainy τ = −0.56) and with photosynthetic photon flux (PPF; dry τ = −0.97; rainy τ = −0.98) were found, indicating a strong hydraulic coupling to atmospheric conditions. Sap flow and transpiration rates of this R. mangle scrub mangrove forest exceeded those of some tropical dry deciduous forests, suggesting adaptations that support water transport in saline environments. The clustered xylem vessels of R. mangle ensure safe sap flow year-round. As an evergreen species, it contributes water to the atmosphere all year-round, underscoring its critical role in the tropical ecohydrological environment. Full article

Oil palms (Elaeis guineensis Jacq.) are increasingly cultivated throughout the humid tropics and are reported to have high transpiration rates. A potential contribution of stem water storage to transpiration has been discussed in previous studies. We assessed the water-use characteristics of oil palms at different horizontal and vertical positions in the plant by using three sap flux techniques, i.e., thermal dissipation probes, the heat ratio method and heat field deformation sensors. In a radial profile of the stem, sap flux densities were low at the outer margin, increased to 2.5 cm under the bark and remained relatively high to the innermost measured depth at 7.5 cm. In a vertical profile of the stem and with further sensors in leaf petioles, we found only small time lags in sap flux densities. Time lags along the flow path are often used for analyzing the contribution of water storage to transpiration. Thus, the small observed time differences in our study would leave only little room for the contribution of water storage to transpiration. However, water storage might still contribute to transpiration in ways that are not detected by time lag analysis. Such mechanisms may be explored in future studies. Full article

The effects of recent climate change, including warm winters and repeated temperature fluctuations during dormancy, can lead to freezing injuries that result in significant economic losses in the fruit industry. This study aimed to examine the physiological responses of ‘Fuji’/M9 apple trees to trunk covering and continuous airflow treatments over 30 days, providing insights into mitigating freezing damage. The temperature difference between the sunlit and shaded sides of the trunk was lower in the whitewashed and foam insulation-covered treatments compared to those covered with newspaper, rice straw, or left uncovered. Under airflow treatment, the temperature difference in the uncovered control was 2.2 °C lower than in the non-airflow group, while no significant difference was observed in the whitewash treatment. Sap flow initiation was observed the earliest in the foam insulation-covered treatment and the latest in the whitewashed treatment. The timing of bud burst followed the order of foam insulation, rice straw, whitewash, newspaper, and the uncovered control. Furthermore, sap flow initiation and the bud burst period were delayed under airflow treatment compared to non-airflow conditions. This study provides fundamental insights into the effects of covering materials and airflow on apple tree physiology during dormancy, offering valuable information to guide future research in this field. Full article

As the average temperature in summer rises and heat waves occur more frequently, the urban heat island (UHI) phenomenon is becoming a social problem. Asphalt road pavement stores heat during the day, raising the surface temperature, and releases the stored heat at night, thereby aggravating the UHI phenomenon. Government authorities often spray water to lower the temperature of road pavement for the safety and convenience of citizens. However, the effect is immediate and does not last long. Therefore, in order to reduce the urban heat island phenomenon by spraying water, the recovery time of the surface temperature must be delayed. In this study, Super Absorbent Polymer (SAP), a highly absorbent polymer that absorbs 100 to 500 times its weight in water, was applied to asphalt road pavement. SAP is commonly used in diapers, feminine hygiene products, soil moisturizers, and concrete, and its scope is gradually expanding. The purpose of this study is to reduce the urban heat island phenomenon by mixing the SAP into asphalt and to increase the latent heat flux by evaporating the water absorbed by the SAP, thereby delaying the recovery time of the surface temperature of the road pavement. In this study, the performance of asphalt mixtures mixed with the SAP and the thermal characteristics according to the mixing amount were analyzed. In this study, the physical properties and temperature reduction performance of the asphalt mixture according to the SAP type and content were studied. The results of indoor and outdoor experiments on asphalt mixtures using the SAP showed that they satisfied the mechanical performance criteria as asphalt pavement materials and that the temperature recovery delay effect was improved. Full article

Heat velocity (V_h) is a key metric to estimate sap flow which is linked to transpiration rate and is commonly measured using thermocouples implanted in plant stems or tree trunks. However, measuring transpiration rates in the Gramineae family, characterized by thin and hollow stems, is challenging. Commercially available sensors based on the measurement of heat velocity can be unaffordable, especially in developing countries. In this work, a real-time heat pulse flux monitoring system based on the heat ratio approach was configured to estimate heat velocity in wheat (Triticum durum L.). The heat velocity sensors were designed to achieve optimal performance for a stem diameter smaller than 5 mm. Sensor parameterization included the determination of casing thermal properties, stabilization time, and time to achieve maximum heat velocity which occurred 30 s after applying a heat pulse. Heat velocity sensors were able to track plant water transport dynamics during phenological stages with high crop water demand (milk development, dough development, and end of grain filling) reporting maximum V_h values in the order of 0.004 cm s⁻¹ which scale to sap flow rates in the order of 3.0 g h⁻¹ comparing to reports from other methods to assess sap flow in wheat. Full article

Phosphorus is a major essential element in plants, and the absorption and transport of P are related to crop growth and productivity. Phosphate (Pi) is absorbed in the roots and transported to the shoot. Plants store surplus Pi in the vacuoles. The characteristics of Pi storage and turnover in various parts of the nodulated soybeans might be related to plant growth and P-use efficiency. This research focused on the changes in the Pi concentrations and Pi contents in each part of young soybean plants grown in Pi-sufficient (50 μM Pi) or Pi-deficient (0 μM Pi) conditions. Also, the Pi flux rate in xylem sap from roots to shoot was determined. The growth of the plants was the same after 7 days of Pi-sufficient and Pi-deficient treatments. During the Pi-deficient period, the Pi concentrations in the roots, leaves, and stems decreased significantly but did not deplete. The decrease in Pi concentration in nodules was much slower than the other parts. After the re-supply of 50 μM Pi in the solution, the Pi concentration increased only a little in each part of the Pi-deficient plants. The Pi concentration and Pi flux in the xylem sap quickly responded to the changes in the Pi concentration in the culture solution. Full article

In the face of ongoing climatic changes, understanding the species’ sap flow responses is of crucial importance for adaptation and resilience of ecosystems. This study investigated diurnal variability and radial sap flux density (Js) in a natural Juniperus drupacea forest on Mt Parnon and determined the climatic factors affecting its total sap flow (Qs). Between July 2021 and March 2022, Granier-type sensors and automatic weather stations monitored Js of J. drupacea trees and environmental factors. Utilizing a multi-point sensor for Js radial profile variability, correction factors were applied to calculate (Qs), ranging from 4.78 to 16.18 L day⁻¹. In drier months of the study period (July–September), Qs progressively increased with increasing PAR and soil temperature, reaching a plateau at maximum values (app. 600 µmol m⁻² s⁻¹ and 26 °C respectively) indicating partial stomatal closure. Whereas, during the wetter period (October–March), when water was no longer a limiting factor, VPD and PAR emerged as significant controllers of stand transpiration. In this period, Qs responded positively to increasing soil water content (θ) only on days with high VPD (>0.5 kPa). The studied J. drupacea stand demonstrated adaptability to varying environmental conditions, crucial for the species’ survival, considering anticipated climate change scenarios. Full article

Forest transpiration plays a vital role in the regional water budget and water supply security of the semi-arid Loess Plateau of northwest China. A thorough understanding and accurate predictions of the variation in the transpiration of forests with important tree species, e.g., Armeniaca sibirica (L.) Lam., are critical for land and water management. Owing to the extreme climatic seasonality and interannual variability, detailed information on the seasonal variation in the transpiration of Armeniaca sibirica plantations and its response to climatic and soil moisture/temperature fluctuations is limited. Therefore, in this study, the sap flux density and meteorological and soil moisture/temperature conditions were continuously monitored during the growing season (May to October) in 2019–2020. The results show the four following features: (1) The mean daily transpiration of the Armeniaca sibirica plantation was 0.31 mm·day⁻¹; (2) the daily transpiration varied nonlinearly with increasing potential evapotranspiration (PET). Transpiration first increased rapidly until reaching the PET threshold of 4 mm·day⁻¹ and then slowly increased within the PET range of 4–8.5 mm·day⁻¹, but thereafter, it decreased slightly when PET exceeded 8.5 mm·day⁻¹; (3) the daily forest transpiration varied with increasing relative extractable soil water content (REW) and soil temperature (ST) following a saturated exponential function; i.e., it first increased until reaching a threshold of 0.5 of REW or 14 °C of ST, but thereafter tended to stabilize; (4) models for estimating the daily forest transpiration were established. According to these models, PET had the greatest limiting effect (32.17%) on forest transpiration during the observation period, while REW and ST showed lower limits at 7.03% and 3.87%, respectively. The findings of this study are useful for understanding and managing the hydrological effects of forests in the semi-arid Loess Plateau as a typical dryland with seasonal droughts. Full article

This trial was carried out over two years in southern Italy. Two grapevine rootstocks, 110R and SO4, were compared to evaluate their ability to extract water from the soil and the effect on the yield and quality of the Cardinal grapevine table cultivar. Therefore, a new approach to plant water consumption based on sap flow was adopted. The earlier and faster water refilling of the xylem in Cardinal onto 110R (C/110R) appears responsible for the earlier evolution of the phenological phases than Cardinal onto SO4 (C/SO4). The maximum length of the principal shoot was reached in Cardinal/110R compared to the C/SO4, while a higher number of lateral shoots with lower internode changed the canopy architecture and light distribution in the C/SO4. The 110R used more water compared to the SO4. It was possible to quantify the real transpired flux of the plant per day: the sap flow was 12.3 L.plant⁻¹.d⁻¹ and 11.7 L.plant⁻¹.d⁻¹ in C/110R in the first and second year, respectively, while it was 14% lower in the alternative graft combination. The overall lower C/SO4 water status does not compromise the production result, with similar or higher-quality aspects compared to the alternative graft combination C/110R, which can be also attributed to the strong resilience of Cardinal to water deficit. Full article