Search Results (640)

Leaf blight and fruit rot caused by Phomopsis vexans are critical issues for eggplant crops. Our study evaluated the biochar amendment, alone and in combination with a foliar spray of silicon dioxide nanoparticles (SiO₂-NPs), on plant performance and disease development. Fungal infection reduced plant growth, with a 22% decline in plant height and a marked decrease in chlorophyll and carotenoid levels. Adding biochar plant height mitigated these effects: the highest dose (30 g) increased plant height in infected plants by 17.1% and increased pigment concentrations and POX and PPO activities. At the same time, the blight index declined. When biochar was combined with SiO₂-NPs, the improvements were more pronounced. In infected plants, the 30 g + SiO₂-NPs treatment produced substantial improvement in plant height (+31.3%) and shoot biomass and restored chlorophyll and carotenoid contents by 63% and 28.1%, respectively. This treatment also produced the lowest blight index and the strongest enzymatic responses. Principal component analyses discriminated treated plants from infected ones. These findings indicate that biochar and SiO₂-NPs can jointly enhance plant resilience to P. vexans infection, reducing its negative impact. Full article

The application of biostimulants is a promising tool for enhancing plant growth and crop quality in the context of sustainable and resilient agricultural production. This study evaluated four microbial biostimulants (IMB1–4) on Sonchus oleraceus L. under field and pot cultivation. Our results indicate that the growing system was a more dominant factor than biostimulants in influencing plant performance. For morphological and growth traits, biostimulants generally had a neutral or negative impact compared with untreated plants, with IMB3 consistently showing the lowest performance. Field-grown plants, especially the untreated ones, excelled in plant weight and leaf count, while pot-grown plants treated with IMB2 and IMB4 achieved higher leaf weight per plant, leaf area, and chlorophyll index (SPAD). Specifically, untreated field plants recorded the highest biomass, whereas IMB2 and IMB4 optimized leaf traits in pots. Biostimulant applications enhanced fat content and energetic value, with IMB1 and IMB2 yielding the highest protein levels. Pot cultivation favored the accumulation of nitrogen, phosphorus, and sodium, while IMB2-treated pot plants proved most effective for maximizing overall nutrient content. The phytochemical profile also varied by system: pot-grown plants yielded higher total phenols, particularly with IMB3, while field-grown plants recorded higher flavonoids, especially with IMB4. Furthermore, untreated or IMB3-treated pot plants exhibited the highest antioxidant activity, significantly outperforming field-grown counterparts. In conclusion, while biostimulants did not improve morphological and growth traits, they significantly enhanced the nutritional and phytochemical quality of S. oleraceus L., particularly in the pot cultivation system, where specific biostimulants (IMB2 and IMB3) resulted in nutrient-dense crops with high antioxidant value. Full article

The transition from High-Pressure Sodium (HPS) to energy-efficient Light-Emitting Diode (LED) supplemental lighting alters the plant thermal environment in controlled environment agriculture (CEA). This study evaluated how three practical supplemental lighting regimes, HPS, LED, and LED supplemented with infrared radiation (LED + IR), influence the physiology, growth, and phytochemical profile of Swiss chard (Beta vulgaris L.). We assessed biomass production, photosynthetic performance, oxidative stress markers (TBARS), and the concentration of primary and secondary metabolites. The LED treatment was superior for biomass production, yielding significant fresh mass while maintaining the lowest leaf nitrate content. Conversely, the addition of IR significantly increased leaf temperature, which suppressed growth but acted as a potent “bio-stress” agent, significantly increasing the total phenolic index. This biofortification, however, significantly decreased photosynthetic pigments (chlorophylls and carotenoids), increased lipid peroxidation (TBARS), and led to the highest accumulation of undesirable nitrates. Our findings reveal a clear growth-defense trade-off, demonstrating that while LED lighting is optimal for maximizing yield and food safety, the targeted application of IR radiation is an effective strategy for enhancing the nutraceutical value of leafy greens, requiring careful management to mitigate negative impacts on growth and quality. Full article

Grapevine growth and physiological performance are strongly influenced by biotic and abiotic stresses occurring during the growing season. Plant stimulants are increasingly applied in viticulture as management tools aimed at supporting plant physiological processes and improving plant performance under variable environmental conditions; however, cultivar-specific responses to different application strategies remain insufficiently characterized. The aim of this study was to evaluate the effects of foliar plant stimulant application strategies differing in application frequency and phenological timing on selected physiological and canopy-related indicators in Slovak grapevine cultivars (Vitis vinifera L.) under field conditions. The assessed parameters included leaf chlorophyll a and b contents, chlorophyll a/b ratio, leaf area index (LAI), vegetation indices (NDVI and PRI), cluster weight, and basic must composition. Grapevines were subjected to three treatment variants: a control without plant stimulant application, a variant with two foliar applications, and a variant with three foliar applications of commercial biostimulants (Tecamin Max, Tecamin Flower, and Tecamin Brix) performed at key phenological stages during the growing season. Plant stimulant applications were associated with variations in leaf chlorophyll content and LAI values, particularly under repeated application strategies. NDVI and PRI complemented leaf-level measurements by capturing cultivar-dependent differences in canopy condition and photosynthetic regulation throughout the season. Responses of cluster weight and must composition to plant stimulant application were moderate and varied among cultivars, indicating cultivar-specific responses. Although no consistent increase in cluster yield was observed, treated variants showed higher sugar content and lower titratable acidity in several cultivars, indicating differences in grape composition and ripening-related traits. Overall, the results indicate that foliar plant stimulant application strategies can influence physiological and canopy-level grapevine traits in a cultivar-dependent manner. The combined use of leaf-level, canopy-level, and spectral indicators provides a practical framework for evaluating plant stimulant strategies under field conditions and supports their application in sustainable viticulture. Full article

Remote sensing advancements have enhanced defoliation monitoring in forests, but distinguishing insect-specific damage from general canopy stress remains challenging due to overlapping spectral signatures. This study addresses this gap by analyzing multispectral reflectance changes in Eucalyptus dunnii caused by Gonipterus sp. n. 2 larval feeding and artificial defoliation (AD). A randomized complete block design with five replicates tested four treatments: No Damage, Medium (100 larvae/tree) and High (200 larvae/tree) larval inoculation, and AD (80% leaf removal). Twenty potted E. dunnii trees were monitored over 16 days using UAV-based multispectral 10-band imagery. Five multispectral flights were conducted during the experiment. The reduction in visible and near-infrared (NIR) reflectance likely reflects structural changes in canopy composition, namely an increased proportion of mature foliage. Both larval feeding and AD treatments decreased reflectance in these spectral regions, probably due to the removal of young leaves and exposure of older, darker leaves. This explanation is inferred from morphological observations; further biochemical measurements would be required to confirm the underlying mechanisms. Larval feeding and AD reduced chlorophyll-related vegetation indices (CVI, NDRE), decreased anthocyanin-related vegetation indices (mARI, ARI), and also caused a drop in relative carotene content (MTVI, CTRI/RE). The effects were strongest in the AD and peaked soon after the treatment, indicating that these pigment effects can mostly and also be attributed to the older leaves becoming more exposed. Statistically significant interactions between date and treatment were found for the pigment-sensitive indices, the Anthocyanin Reflectance Index (ARI) and the Chlorophyll Vegetation Index (CVI). They displayed opposite reflectance trends—CVI increased while ARI decreased—but followed a consistent pattern aligned with insect feeding. EVI values also exhibited a distinguishable pattern that matched this trend. Due to the inherent difficulty of studying insect feeding in natural settings, AD trials may serve as a practical proxy for assessing the impact of pest-induced damage on vegetation reflectance and physiological indices. Full article

Light availability is a key environmental factor influencing plant functional traits and ecological strategies. To investigate how natural populations of Iris pumila respond to contrasting irradiance, we conducted an in situ reciprocal transplant experiment using clonal genotypes from two natural populations, each originating from an open dune and a shaded forest habitat. Leaves collected from each of the replanted and transplanted genotypes were analyzed for structural (specific leaf area—SLA, leaf dry matter content—LDMC), physiological (specific leaf water content—SLWC, photosynthetic pigments) and biochemical (peroxidase—POD, glutathione reductase—GR, phenolics and anthocyanins) traits. Shade-grown individuals developed thinner leaves with higher SLA and chlorophyll content, enhancing light-harvesting efficiency, whereas sun-exposed plants exhibited greater LDMC, increased POD and GR activities and higher anthocyanin levels—traits consistent with enhanced photoprotection under high irradiance. All genotypes exhibited pronounced plasticity to light intensity, with habitat exerting a stronger influence on trait expression than population origin. To evaluate oxidative balance, we proposed the ODAC index (Oxidative Damage to Antioxidant Capacity), which integrates lipid peroxidation with antioxidant capacity. ODAC values revealed consistent population-level differences, with higher values in Dune genotypes across habitats, indicating a constitutively elevated oxidative load relative to antioxidant protection and suggesting differentiation in redox regulation between populations. Overall, leaf trait variation in I. pumila appears to be primarily driven by plastic responses to light conditions, while differentiation in oxidative physiology contributes to functional divergence between populations. Full article

This study employs a hybrid methodology that integrates a physical process-based radiative transfer (RT) model and machine learning regression to assess three key wheat crop traits: leaf area index (LAI), leaf chlorophyll content (LCC), and canopy chlorophyll content (CCC). The non-imaging hyperspectral data collected proximally using the ASD FieldSpec Spectroradiometer were spectrally resampled to 269 spectral bands ranging from 400 to 1000 nm for the retrieval of these crop traits. Upon validating against in situ measurements, good accuracies in terms of NRMSE values, 10.65%, 11.63%, and 13.85%, were achieved for LAI, LCC, and CCC, respectively. Full article

Common vetch (Vicia sativa L.) is a well-adapted winter legume in the Mediterranean area, used for both forage and grain production. Phosphorus (P) is a key nutrient influencing plant growth, development, yield, and nutritional quality. This study evaluated how phosphorus availability (0 vs. 60 kg ha⁻¹ P₂O₅) affected the growth, physiological characteristics, yield and environmental resource-use efficiency of two common vetch cultivars, BK-45 and Evinos, over two growing seasons (2020–2021 and 2021–2022). Phosphorus fertilization significantly enhanced vegetative growth, increasing plant height (37.5%) and leaf area index (57%) compared with the control. Improved physiological performance was also observed, as P application increased the chlorophyll content (SPAD) and normalized difference vegetation index (NDVI), particularly during later growth stages. Evinos showed better growth and chlorophyll content around anthesis, whereas BK-45 retained more chlorophyll at maturity. These influences on canopy development and photosynthetic capacity translated into improved yield components, with increases in seeds per pod (40%) and pods per plant (33%), resulting in a higher seed yield (0.127 kg m⁻² vs. 0.06 kg m⁻² in the control). The dry biomass increased by 50%, with BK-45 showing the strongest response to P fertilization. P fertilization also improved water-use efficiency (WUE) and radiation-use efficiency (RUE), thereby promoting resource use and also the sustainability of the crop. These findings underscore that phosphorus fertilization plays a key role in improvement of common vetch seed yield, forage yield and the sustainability of the cultivars, with the interactions depending on the seasonal variation. Full article

Fruit quality and yield of citrus orchards are co-regulated by complex interactions among soil properties, microbial communities, and plant physiological processes. However, systematic studies that integrate the soil–microbe–plant–fruit continuum remain limited. This study selected four representative ponkan orchards based on yield and fruit quality performance, and systematically determined and correlated key indicators in the soil–plant–fruit continuum. The results showed that the orchards with higher comprehensive performance exhibited more suitable soil pH, higher contents of soil organic matter and available nutrients, as well as higher activities of soil enzymes including urease and acid phosphatase. Compared with the orchards with lower comprehensive performance, soil bacterial and fungal Chao1, Shannon, and Simpson indices were higher in the orchards with higher comprehensive performance. Among the dominant phyla, the relative abundance of Proteobacteria was significantly higher, while that of Actinobacteria was significantly lower. Leaf photosynthetic indexes (chlorophyll content, net photosynthetic rate, Rubisco activity) of the higher-performing orchards were also significantly higher. Correlation analysis showed that soil microbial diversity and Proteobacteria were significantly positively correlated with soil nutrients, enzyme activities, leaf photosynthesis, fruit quality and yield, while Actinobacteria showed the opposite trend. These results provide a theoretical basis for soil management and high-quality cultivation of ponkan orchards. Full article

Leaf and spike diseases can significantly reduce wheat yield and grain quality. To mitigate these impacts, an integrated disease management approach can be adopted, incorporating measures such as the use of resistant cultivars, fungicides and nitrogen fertilization. This study aimed to evaluate the impact of these practices on chlorophyll a fluorescence, yield components, and the technological quality of wheat grains. The area under the disease progress curve (AUDPC) was correlated with the maximum efficiency of photosystem II (PSII) photochemistry (F_v/F_m), as measured at the dough development stage (ZGS80) under field conditions, which also affected quality parameters. Additionally, an increase in AUDPC values reduced the thousand kernel weight (TKW) and test weight (TW). Conversely, AUDPC values for tan spot, powdery mildew and leaf rust were positively related to ash content (affecting flour color), protein content (PC) and grain falling number. Both the recommended nitrogen rate (130 kg ha⁻¹) and the high rate (200 kg ha⁻¹) increased grain protein content (PC) and gluten index (GI), while maintaining dough stability and water absorption. Fungicide application increased flour lightness and yellowness. Overall, integrated disease management combining moderately resistant cultivars, fungicide applications and nitrogen fertilization reduced AUDPC values, increased F_v/F_m (indicating optimal physiological performance) and ensured yield components and maintenance of wheat technological quality. Full article

To assess digestate’s efficacy as a fertilizer for basil development, a two-year pot experiment was established, comprising four fertilization treatments: namely, mineral fertilizer (F), digestate (D), combined mineral fertilizer and digestate (1:1, FD), and unfertilized control (C). Key metrics assessed included plant height, chlorophyll concentration index (CCI), total biomass (TB), leaf production (LP), essential oil yield, and composition. Post-harvest analysis evaluated nutrient and heavy metal content and pathogen contamination in the growing substrate and leaves. FD treatment produced the highest TB (68.2 g plant⁻¹) and LP (52.7 g plant⁻¹). Digestate application substantially enhanced substrate nutrient availability, increasing extractable phosphorus by 68.5%, potassium by 134.4%, and organic matter by 54.7%. The essential oil yield was significantly higher in the control plants. whereas different fertilization regimes altered secondary metabolite synthesis. Specifically, fertilization with digestate favored sesquiterpenes synthesis, inorganic fertilization enhanced methyleugenol and β-farnesene synthesis, and the control showed higher limonene, eugenol, and linalool. Heavy metal accumulation in the growing substrate was negligible, remaining well within regulatory limits. Salmonella spp., were not detected. Pathogen concentration in the growing substrate was low, while Enterococcus faecalis levels were marginally below EU safety limits (100 cfu g⁻¹) on the leaves. Continuous monitoring of soil chemical properties and plant products after digestate application is essential to ensure soil health and food safety. Full article

Leaf chlorophyll content (LCC) is a key physiological parameter affecting plant growth and development. Rapid and non-destructive monitoring of LCC using hyperspectral remote sensing is crucial for promoting precision agriculture. In this study, hyperspectral data of apple canopy leaves at different phenological stages were collected alongside their corresponding SPAD values (representing LCC) to construct a dataset. Two types of spectral features were extracted: (1) optimized spectral index combinations; and (2) feature bands selected using the Successive Projections Algorithm (SPA). Based on these features, three machine learning models—Support Vector Machine (SVM), Least Squares Support Vector Machine (LSSVM), and Chaos Evolution Optimization-enhanced LSSVM (CEO-LSSVM)—were developed to estimate SPAD values. The results indicate that the constructed optimal spectral index combinations exhibit superior sensitivity in SPAD estimation compared to the feature bands selected by SPA. Specifically, during the physiological fruit drop stage, the CEO-LSSVM model based on spectral indices achieved a test set R² of 0.851, surpassing the SPA-based model (R² = 0.813). Regarding model performance, the CEO-LSSVM demonstrated the highest accuracy and robustness across all stages. In the fruit drop period, using optimized spectral indices, it achieved an RMSE of 1.338, significantly outperforming the LSSVM (RMSE = 1.703) and SVM (RMSE = 2.409) models. This superiority was further evident in the fruit enlargement stage, where the CEO-LSSVM model reached a peak test set R² of 0.868 and the lowest RMSE of 1.254. The integrated model combining optimized spectral indices and CEO-LSSVM provides an efficient and high-precision approach for hyperspectral SPAD estimation in apple canopies, effectively addressing the challenges of inversion modeling in arid oasis environments. Full article

Water deficit during the grain filling stage is a major threat to sustainable crop production, especially in arid and semi-arid regions. This study aims to investigate the comprehensive effects of water deficit on the photosynthetic characteristics, dry matter accumulation, and yield formation of triticale (× Triticosecale wittmack). The photosynthetic characteristics of the flag leaf and spike organs (awn, glume, and lemma) and their relationship with yield were analyzed during the grain filling stage when the triticale plant was subjected to adequate water supply and water deficit 0, 7, 14, 20, and 25 days after anthesis. The results showed that under normal water supply, photosynthesis was reduced by 27.5% and 34.4% in awned and awnless spikes, respectively, at 25 days after anthesis (25DAAs), compared to flag leaves. Under water deficit at 25DAAs, photosynthesis was reduced by 50.5% and 60.9% in awned and awnless spikes, respectively. Water deficit reduced RWC and chlorophyll content in flag leaf and spike organs, and the changes in RWC and chlorophyll content in spike organs were less than those in flag leaf. The differences in grain yield, biomass, and harvest index of awned and awnless triticale were not significant under adequate water supply. Grain yield of awned and awnless triticale was reduced by 23.7 and 24.6%, respectively, under water deficit compared to adequate water supply. Our results suggest that awnless plants suffer from drought more than awned plants in grain-filling stage, where the role of awns is critical. Full article

This data descriptor presents a dataset comprising crop and soil parameters measured in winter wheat fields near the town of Knezha, Bulgaria. The data were collected as part of a project evaluating the potential of vegetation indices derived from Sentinel-2 satellite imagery to predict biophysical and biochemical crop parameters. The core dataset consists of measurements obtained from 20 m × 20 m field plots and includes a broad range of parameters: leaf area index, fraction of absorbed photosynthetically active radiation, vegetation cover fraction, chlorophyll content, above-ground biomass, plant nitrogen content, biological yield, surface soil moisture, spectral reflectance, plant density, crop height, visual assessments of disease or pest damage, and data on weed occurrence. The dataset is complemented by unmanned aerial vehicle imagery, crop calendars, and field management information. The main soil types in the study area were characterized through soil profiles, while meteorological data were obtained from an automated weather station. The data were collected during the 2016–2017 and 2017–2018 agricultural seasons. The dataset is freely available for download and serves as a valuable resource for researchers in remote sensing—particularly for validating satellite-derived products—as well as for specialists involved in winter wheat monitoring, modeling, and agronomic studies. Full article

While increasing planting density is a viable strategy for enhancing maize yield, it concurrently elevates the risks of lodging and accelerated leaf senescence due to intensified inter-plant competition, which can ultimately compromise yield stability. A field experiment was conducted in Heilongjiang Province and the study investigated two maize cultivars, JNK728 (Jingnongke 728) and SD5 (Saide 5), under high-density planting conditions (90,000 plants ha⁻¹). The treatments were arranged in a factorial design, incorporating four nitrogen levels (0, 120, 240, and 360 kg N ha⁻¹) in combination with the presence or absence of a chemical regulator (30% diethyl aminoethyl hexanoate · ethephon), with water serving as the control. Results demonstrated that the integration of 240 kg N ha⁻¹ with chemical regulation significantly enhanced photosynthetic capacity—elevating chlorophyll content (SPAD), net photosynthetic rate (Pn), and activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) and phosphoenolpyruvate carboxylase (PEPCase)—while improving canopy structure through increased leaf area index (LAI) and optimized light distribution. This strategy also reinforced lodging resistance by optimizing plant morphology (reducing plant height and center of gravity), strengthening basal internodes (increasing stem diameter, dry weight per unit length, and mechanical strength), and promoting accumulation of stem structural components (cellulose, hemicellulose, lignin). Additionally, it facilitated post-anthesis nitrogen translocation to grains and up-regulated key nitrogen metabolism enzymes (glutamate synthetase-GS, glutamate dehydrogenase-GDH, and glutamate-pyruvate transaminase-GPT), thereby boosting nitrogen use efficiency. In contrast, excessive nitrogen (360 kg N ha⁻¹) suppressed these benefits and increased lodging. Consequently, the combined application of 240 kg N ha⁻¹ with chemical regulation achieved the highest yield, proving an effective approach for synergistically enhancing photosynthesis, lodging resistance, and nitrogen utilization in high-density maize systems. Full article