Search Results (142)

Glycine betaine (GB) is a compatible solute that enhances plant tolerance to abiotic stresses, yet its role in fruit crops remains insufficiently explored. This study assessed whether GB improves drought tolerance in Passiflora edulis Sims f. flavicarpa, a crop sensitive to irregular rainfall. A 3 × 2 × 2 factorial design was employed, combining three drought levels (control, mild, and severe), two propagation methods (seedlings and cuttings), and two GB treatments (0 and 100 mM), with 60 plants and five replicates. Plants were grown under controlled conditions, and irrigation was adjusted to maintain target field capacities. Chlorophyll content was monitored daily, and agronomic and physiological traits were measured after 45 days. GB application influenced leaf water dynamics and stress responses. Cuttings generally showed clearer improvements in drought tolerance when treated with GB, while seedlings exhibited more variable outcomes. These differences appear linked to the propagation method and developmental stage as cuttings were at a more advanced phase, whereas seedlings remained vegetative. Overall, the results demonstrate that exogenous GB can enhance drought tolerance in passion fruit, although its effectiveness is propagation-dependent and context-specific, highlighting the need to tailor its application to cultivation practices. Full article

Understanding the propagation of drought from meteorological anomalies to vegetation stress is critical for risk assessment, yet traditional methods often fail to capture the complete spatiotemporal evolution of drought events. This study identified meteorological and vegetation drought events across three dimensions (two-dimensional space and one-dimensional time) in the Loess Plateau of China from 2001 to 2022. As a result, the area, duration, severity, and migration of each event were characterized to reveal their spatiotemporal patterns. We identified 39 meteorological and 63 vegetation events, which show strong concordance with historical records. Results show that while meteorological droughts exhibited cyclical patterns, vegetation droughts showed a significant mitigating trend post-2010. The central Loess Plateau consistently emerged as the primary hotspot for drought frequency and severity, with events concentrated in spring and summer. Analysis of 20 matched meteorological-vegetation event pairs indicates that post-2010, the response of vegetation to meteorological drought was delayed, suggesting enhanced drought resistance of the vegetation following ecological restoration. These findings provide a scientific basis for regional drought risk assessment and offer quantitative evidence of the effectiveness of ecological restoration. Full article

Drought stress caused by continuous global warming poses a severe challenge to the growth and development of Nitraria tangutorum. Abscisic acid has an important regulatory function in the process of plants responding to drought stress. This study took the N. tangutorum seedlings of Zhangye provenance 2-17-16 genealogy as the research object to explore the physiological mechanism of how different concentrations of exogenous ABA alleviate drought damage in N. tangutorum. The results showed that exogenous ABA could promote the growth and increase the leaf relative water content of N. tangutorum seedlings under drought stress. It alleviates the photosynthetic inhibition phenomenon of N. tangutorum seedlings under drought stress by regulating the photoprotective mechanism and energy distribution efficiency of photosystem II. It also alleviates the drought damage of N. tangutorum by increasing the content of osmotic-adjustment substance contents such as soluble sugar, soluble protein, proline, and starch, as well as enhancing the activity of antioxidant enzymes such as POD, SOD, and CAT. The comprehensive analysis showed that 20 μM and 30 μM ABA have the best alleviating effects on the drought damage of N. tangutorum seedlings. This study provides a theoretical basis for the restoration, propagation, and protection of N. tangutorum, and it is of great significance for maintaining the balance and stability of desert ecosystems. Full article

The Loess Plateau frequently endures droughts, and the propagation process has grown more intricate due to the interplay of climate change and human activities. This study developed the Standardized Precipitation Evapotranspiration Index (SPEI) and the Standardized Soil Moisture Index (SSMI) on a 3-month scale and examined the spatiotemporal characteristics and driving mechanisms of drought propagation from meteorological to agricultural drought utilizing cross-wavelet analysis, grey relational analysis, and the optimal parameter-based geographical detector (OPGD) model. The results demonstrate a substantial seasonal correlation between meteorological and agricultural droughts in spring, summer, and autumn, as evidenced by cross-wavelet coherence analysis (wavelet coherence > 0.8, p < 0.05). Lag analysis utilizing grey relational degree (>0.8) indicates that drought propagation generally manifests with a temporal delay of 1–3 months, with the shortest lag observed in spring (average 1.2 months) and the longest in winter (average 3.1 months). Distinct spatial heterogeneity is seen within geomorphological divisions: the loess wide valley hills and loess beam hills divisions exhibit the highest propagation rates (0.64 and 0.59), whereas the loess tableland and soil–stone hills divisions have lower propagation (around 0.50). The OPGD results reveal that precipitation, soil moisture, and temperature are the principal contributing factors, although their effects differ among geomorphological types. Interactions among components exhibit synergistic enhancement effects. This study improves our comprehension of seasonal and geomorphological heterogeneity in drought propagation from meteorological to agricultural droughts and provides quantitative evidence to support early drought warnings across various divisions, agricultural risk assessment, and water security strategies in the Loess Plateau. Full article

Gross primary productivity (GPP) is a key carbon flux in the global carbon cycle, and understanding the inhibitory effects of drought on GPP and its underlying mechanisms is crucial for understanding carbon–climate feedback. However, current research has not sufficiently addressed the threshold dynamics and regional differentiation of GPP responses to the synergistic effects of meteorological drought (MD) and soil moisture drought (SD), particularly in the drought-sensitive Mongolian Plateau. This study focuses on the Mongolian Plateau from 1982 to 2021, using the standardized precipitation index (SPI) and standardized soil moisture index (SSI) to characterize MD and SD, respectively. The study combines the three-threshold run theory, cross-wavelet analysis, Spearman correlation analysis, and copula models to systematically investigate the variation characteristics, propagation patterns, and the probability and thresholds for triggering GPP loss under different time scales (monthly, seasonal, semi-annual, and annual). The results show that (1) both types of droughts exhibited significant intensification trends, with SD intensifying at a faster rate (annual scale SSI12 trend: −0.34/10a). The intensification trend strengthened with increasing time scales. MD exhibited high frequency, short duration, and low intensity, while SD showed the opposite characteristics. The most significant aridification occurred in the central region. (2) The average propagation time from MD to SD was 11.22 months. The average response time of GPP to MD was 10.46 months, while the response time to SD was significantly shorter (approximately 2 months on average); the correlation between SSI and GPP was significantly higher than that between SPI and GPP. (3) The conditional probability of triggering mild GPP loss (e.g., <40^th percentile) was relatively high for both drought types, and the probability of loss increased as the time scales extended. Compared to MD, SD was more likely to induce severe GPP loss. Additionally, the drought intensity threshold for triggering mild loss was lower (i.e., mild drought could trigger it), while higher drought intensity was required to trigger severe and extreme losses. Therefore, this study provides practical guidance for regional drought early-warning systems and ecosystem adaptive management, while laying an important theoretical foundation for a deeper understanding of drought response mechanisms. Full article

Diploid Vaccinium fuscatum is a wild blueberry species with a low chilling requirement, an evergreen growth habit, and soil adaptability to southeast US growing regions. Regardless of its potential to improve the abiotic and biotic resilience of cultivated blueberries, this species has rarely been used for blueberry breeding. One hurdle is the ploidy barrier between diploid V. fuscatum and tetraploid cultivated highbush blueberries. To overcome the ploidy barrier, vegetative shoots micro-propagated from one genotype of V. fuscatum, selected because it grew vigorously in vitro and two southern highbush cultivars, ‘Emerald’ and ‘Rebel,’ were treated with colchicine. While shoot regeneration was severely repressed in ‘Emerald’ and ‘Rebel,’ shoot production from the V. fuscatum clone was not compromised at either 500 µM or 5000 µM colchicine concentrations. Due to the high number of shoots produced in vitro via the V. fuscatum clone shoots of this clone that had an enlarged stem diameter in vitro were subjected to flow cytometer analysis to screen for induced polyploidy. Sixteen synthetic tetraploid V. fuscatum, one synthetic octoploid ‘Emerald,’ and three synthetic octoploid ‘Rebel’ were identified. Growth rates of the polyploid-induced mutants were reduced compared to their respective wildtype controls. The leaf width and length of synthetic tetraploid V. fuscatum and synthetic octoploid ‘Emerald’ was increased compared to the wildtypes, whereas the leaf width and length of synthetic octoploid ‘Rebel’ were reduced compared to the wildtype controls. Significant increases in stem thickness and stomata guard cell length were found in the polyploidy-induced mutant lines compared to the wildtypes. In the meantime, stomata density was reduced in the mutant lines. These morphological changes may improve drought tolerance and photosynthesis in these mutant lines. Synthetic tetraploid V. fuscatum can be used for interspecific hybridization with highbush blueberries to expand the genetic base of cultivated blueberries. Full article

To ensure the normal water status of apple rootstock softwood cuttings during the initial stage of cutting, a drought stress monitoring model was designed. The model is optimized based on the YOLOv11n-seg instance segmentation model, using the leaf curl degree of cuttings as the classification basis for drought-stress grades. The backbone structure of the IMYOLOv11n-seg model is improved by the C3K2_CMUNeXt module and the multi-head self-attention (MHSA) mechanism module. The neck part is optimized by the KFHA module (Kalman filter and Hungarian algorithm model), and the head part enhances post-processing effects through HIoU-SD (hierarchical IoU–spatial distance filtering algorithm). The IMYOLOv11-seg model achieves an average inference speed of 33.53 FPS (frames per second) and the mean intersection over union (MIoU) value of 0.927. The average recognition accuracies for cuttings under normal water status, mild drought stress, moderate drought stress, and severe drought stress are 94.39%, 93.27%, 94.31%, and 94.71%, respectively. The IMYOLOv11n-seg model demonstrates the best comprehensive performance in ablation and comparative experiments. The automatic humidification system equipped with the IMYOLOv11n-seg model saves 6.14% more water than the labor group. This study provides a design approach for an automatic humidification system in protected agriculture during apple rootstock cutting propagation. Full article

Accurate reservoir inflow forecasting is vital for effective water resource management. Reliable forecasts enable operators to optimize storage and release strategies to meet competing sectoral demands—such as water supply, irrigation, and hydropower scheduling—while also mitigating flood and drought risks. To address this need, in this study, we propose a novel time-variant encoder–decoder (ED) model designed specifically to improve multi-step reservoir inflow forecasting, enabling accurate predictions of reservoir inflows up to seven days ahead. Unlike conventional ED-LSTM and recursive ED-LSTM models, which use fixed encoder parameters or recursively propagate predictions, our model incorporates an adaptive encoder structure that dynamically adjusts to evolving conditions at each forecast horizon. Additionally, we introduce the Expected Baseline Integrated Gradients (EB-IGs) method for variable importance analysis, enhancing interpretability of inflow by incorporating multiple baselines to capture a broader range of hydrometeorological conditions. The proposed methods are demonstrated at several diverse reservoirs across the United States. Our results show that they outperform traditional methods, particularly at longer lead times, while also offering insights into the key drivers of inflow forecasting. These advancements contribute to enhanced reservoir management through improved forecasting accuracy and practical decision-making insights under complex hydroclimatic conditions. Full article

Thylakoid rhodanese-like protein (TROL) serves as a thylakoid membrane hinge linking photosynthetic electron transport chain (PETC) complexes to nicotinamide adenine dinucleotide phosphate (NADPH) synthesis. TROL is the docking site for the flavoenzyme ferredoxin-NADP⁺ oxidoreductase (FNR). Our prior work indicates that the TROL-FNR complex maintains redox equilibrium in chloroplasts and systemically in plant cells. Improvement in the knowledge of redox regulation mechanisms is critical for engineering stress-tolerant plants in times of elevated global drought intensity. To further test this hypothesis and confirm our previous results, we monitored light-independent ROS propagation in the leaves of Arabidopsis wild type (WT), TROL knock-out (KO), and TROL ΔRHO (RHO-domain deletion mutant) mutant plants in situ by using confocal laser scanning microscopy with specific fluorescent probes for the three different ROS: O₂^·−, H₂O₂, and ¹O₂. Plants were grown under the conditions of normal substrate moisture and under drought stress conditions. Under the drought stress conditions, the TROL KO line showed ≈32% less O₂^·− while the TROL ΔRHO line showed ≈49% less H₂O₂ in comparison with the WT. This research confirms the role of dynamical TROL-FNR complex formation in redox equilibrium maintenance by redirecting electrons in alternative sinks under stress and also points it out as promising target for stress-tolerant plant engineering. Full article

Pine wilt disease (PWD), caused by Bursaphelenchus xylophilus Steiner & Buhrer (pine wood nematodes, PWN), impacts forest carbon sequestration and climate change. However, satellite-based PWD monitoring is challenging due to the limited spatial resolution of Sentinel’s MSI sensor, which reduces its sensitivity to subtle biochemical alterations in foliage. We have, therefore, developed a slope product index (SPI) for effective detection of PWD using single-date satellite imagery based on spectral gradients in the visible and near-infrared (VNIR) range. The SPI was compared against 15 widely used vegetation indices and demonstrated superior robustness across diverse test sites. Results show that the SPI is more sensitive to changes in chlorophyll content in the PWD detection, even under potentially confounding conditions such as drought. When integrated into Random Forest (RF) and Back-Propagation Neural Network (BPNN) models, SPI significantly improved classification accuracy, with the multivariate RF model achieving the highest performance and univariate with SPI in BPNN. The generalizability of SPI was validated across test sites in distinct climate zones, including Zhejiang (accuracyZ_Mean = 88.14%) and Shandong (accuracyS_Mean = 78.45%) provinces in China, as well as Portugal. Notably, SPI derived from Sentinel-2 imagery in October enables more accurate and timely PWD detection while reducing field investigation complexity and cost. Full article

In recent years, droughts and extreme weather events have witnessed increasing frequency around the globe, leading to a growing number of issues related to soil cracking that severely impact the stability of engineering projects and ecological environments. This study mainly investigates the cracking of clay in arid areas of Xinjiang. An experiment is conducted in a climate simulation laboratory, in which we explored the evolution of soil drying cracks under different (straight/curved) boundary constraints. The crack development process is quantitatively described through the use of digital imaging technology and by combining parameters such as crack rate, fractal dimension, and water-holding performance at different boundaries. The following conclusions were drawn: Under curved boundary conditions, cracks expand in a curve-like manner, and the cracks in the boundary area are densely distributed. However, under straight boundary conditions, penetrating straight cracks are formed, and the soil blocks present as regular polygons. Boundary conditions significantly impact the residual water content. Under straight boundary conditions, the residual masses of strongly and weakly bound water are significantly higher than those under curved boundary conditions. The complexity of the crack network under the curved boundary condition is higher, and its fractal dimension is significantly greater than that under the straight boundary condition. A quantitative analysis based on the use of digital image processing technology indicates that the boundary geometry has a significant controlling effect on the crack propagation path. This research provides guidance on the prevention and control of soil engineering cracking and damage in arid regions. Full article

Black elder (Sambucus nigra L.) is a temperate shrub with flowers and fruits that are edible after processing. This species is not yet widely known in the global agricultural sector, but its adaptability and drought tolerance may generate more interest in this crop. Our study aimed to find suitable micropropagation techniques for the black elder ‘Albida’ and compare suitable statistical methods for evaluating multiplication and rooting. For micropropagation, we tested the Murashige and Skoog (MS) growth medium with selected auxins and cytokinins. Five proliferation MS media containing 1, 2, and 4 mg/L BAP or 0.5 and 1 mg/L TDZ were tested. To induce root formation, three types of auxins were tested at a concentration of 1 mg/L in a 50% MS medium: IBA, IAA, and NAA. Data analysis was performed using different parametric and nonparametric tests to robustly capture the effects of treatments across varying distributional scenarios in developing explants subjected to the interactions of internal native and externally added plant growth regulators. The average multiplication rate ranged from 1.6 to 2.0 shoots per explant. High multiplication was recorded on the MS medium with 1 mg/L 6-benzylaminopurine. The root number per rooted explant was highly variable, ranging from 3.0 to 12.0 roots per explant. The highest average root number result was observed when 1 mg/L α-naphthalenacetic acid was used. All rooted plants were successfully acclimated to normal growing conditions. This in vitro propagation protocol allows for the production of hundreds to thousands of rooted plants from one initial explant within one year, enabling faster introduction to the agronomic sector. Full article

In order to maintain adequate hydration of apple rootstock softwood cuttings during the initial stage of cutting, a drought stress grading model based on machine vision was designed. This model was optimized based on the U-Net (U-shaped Neural Network), and the petiole morphology of the cuttings was used as the basis for classifying the drought stress levels. For the CU-ICA-Net model, which is obtained by improving U-Net with the ICA (Improved Coordinate Attention) module designed using a cascaded structure and dynamic convolution, the average accuracy rate of the predictions for the three parts of the cuttings, namely the leaf, stem, and petiole, is 93.37%. The R² values of the prediction results for the petiole curvature k and the angle α between the petiole and the stem are 0.8109 and 0.8123, respectively. The dataset used for model training consists of 1200 RGB images of cuttings under different grades of drought stress. The ratio of the training set to the test set is 1:0.7. A humidification test was carried out using an automatic humidification system equipped with this model. The MIoU (Mean Intersection over Union) value is 0.913, and the FPS (Frames Per Second) value is 31.90. The test results prove that the improved U-Net model has excellent performance, providing a method for the design of an automatic humidification control system for industrialized cutting propagation of apple rootstocks. Full article

Urban expansion has led to two significant environmental challenges: the reduction in green spaces and the rise in urban temperatures, decreasing city livability. Green roofs have emerged as a sustainable solution to mitigate these issues, offering ecological and economic benefits while improving building energy efficiency. Some species of the genus Sedum, particularly Sedum sediforme and Sedum album, are ideal for such green infrastructure due to their non-aggressive and superficial root system, high drought tolerance, low nutrient needs, pest and disease resistance, and metabolic adaptability during dry periods. This study aims to optimize the large-scale production of two native ecotypes of S. sediforme and S. album from the Valencian Community through an efficient propagation system that enables uniform plant production in limited space. For this purpose, we have developed micropropagation systems that allow a rapid multiplication of these two species. A direct morphogenesis system was established using axenic plant shoots, and a protocol for adventitious organogenesis from leaves was also developed. These methods significantly enhance propagation speed, spatial efficiency, and plant uniformity. Notably, the metabolic plasticity of S. sediforme and S. album reduces abiotic stress during acclimatization, promoting efficient ex vitro establishment and functional integration into extensive green roof ecosystems. Full article

Understanding the propagation dynamics from meteorological to hydrological droughts, particularly in regions heavily influenced by human activities, is essential for the effective monitoring and prevention of hydrological drought risks. This study focuses on the Haihe River Basin, investigating the evolution of meteorological and hydrological droughts using the Standardized Precipitation and Evapotranspiration Index and the Standardized Runoff Index, supplemented by run theory analysis. Using correlation analysis, we examine the propagation lag times between meteorological and hydrological droughts. Our results indicate a worsening drought trend in the Haihe River Basin over the past six decades. Notably, a turning point occurred in 1991, where meteorological droughts began to abate, while hydrological droughts intensified, highlighting a divergence in trends between meteorological and hydrological droughts. We identify four distinct pathways for the transition from meteorological to hydrological droughts in the region. This study identifies a hydrological drought lag time of 3 months. The occurrence of droughts in the Haihe River Basin is becoming increasingly frequent. Furthermore, our findings reveal that the severity of hydrological droughts is increasingly exceeding that of meteorological droughts, and the influence of meteorological conditions on hydrological droughts is diminishing, while human activities may become a more significant contributing factor. The findings from this research enhance our comprehension of how drought propagation trends and characteristics are shaped by significant human influences, thereby offering pivotal insights for managing water resources at the basin level. Full article