Search Results (325)

The aim of the study was to determine the effect of cultivar and nitrogen fertilization on the morphological and physiological traits and yield of soybean (Glycine max (L.) Merrill) grown in central-eastern Poland. In a strict, two-factor field experiment, four soybean cultivars were used: ‘Abelina’, ‘Malaga’, ‘Coraline’, and ‘Petrina’, and three nitrogen rates: 0, 30, and 60 kg N ha⁻¹. The moderate rate (N30) was applied before sowing, while the higher rate (N60) was divided into two parts, with 50% applied before sowing and 50% top-dressed at BBCH 61. The studies were conducted during two growing seasons. It was shown that both the cultivar and nitrogen fertilization significantly affected plant height, leaf area index (LAI), leaf greenness index (SPAD), and chlorophyll fluorescence indices (Fv/Fm, PI). The interaction among cultivar, fertilization, and years was significant for SPAD and Fv/Fm index, indicating a strong influence of environmental factors on plant response. Nitrogen fertilization increased plant height and chlorophyll content but reduced fluorescence indices. Among the cultivars studied, the late-season cultivar ‘Malaga’ was characterized by the highest SPAD index (502), Fv/Fm (0.800), and PI values (4.3), and achieved the highest seed yield (5.06 t ha⁻¹) and thousand-seed weight (230 g). In contrast, the medium-season cultivar ‘Abelina’ showed the lowest SPAD (454), and significantly lower Fv/Fm and PI values (0.790 and 3.51, respectively), resulting in the lowest yield (4.25 t ha⁻¹) and TSW (169.7 g). The application of a moderate rate of nitrogen (N30) improved the physiological indicators of plants and elements of yield structure without reducing the potential photochemical efficiency of PSII, while a higher rate (N60) did not result in a significant increase in yield, despite a greater number of pods and seeds per plant, which may have been due to a reduction in thousand-seed weight. The results highlight the importance of cultivar selection and moderate N fertilization of soybean grown in temperate climates and indicate the need for further research on the physiological mechanisms that determine cultivar-specific nitrogen use efficiency and yield stability under environmental stress. Full article

This study determined the optimal nitrogen–phosphorus–potassium (N-P-K) ratios for maximizing growth performance in spinach (Spinacia oleracea), bok choy (Brassica rapa subsp. chinensis), and Chinese cabbage (Brassica rapa pekinensis). A response surface methodology experiment with 15 N-P-K treatments (0–1.5 g/L per nutrient) was conducted under controlled conditions. Growth parameters including plant height, biomass, leaf area, and root development were measured after four weeks and analyzed using principal component analysis and Pearson correlation analysis. Optimal ratios were species-specific: spinach achieved maximum performance with N-P-K = 2-0-2 (13.15 g fresh weight, 13.88 g total biomass), bok choy with N-P-K = 0-2-2 (2631.31 mm² leaf area, 4.42 mm stem diameter), and Chinese cabbage with N-P-K = 2-0-2 (14.14 cm height, 9883.44 mm² leaf area). High nitrogen levels were negatively correlated with root development across all species (r = −0.531 to −0.690, p < 0.05). These findings demonstrate that species-specific nutrient management strategies are essential for optimal leafy vegetable production. Balanced N-P-K ratios prevent nutrient toxicity while maximizing growth, providing evidence-based guidelines for precision fertilization in controlled environment agriculture. Full article

The ecological strategies of understory shrubs are critical for maintaining the structure and function of forest understory vegetation. Understanding the assembly mechanisms of these shrub communities is a central issue in modern ecology. To address this, our study was conducted in the typical red soil regions of Jiangxi, China, focusing on secondary forests (including both broadleaved and coniferous types) of similar stand age. We aimed to assess the effects of various environmental factors—such as soil pH, total nitrogen content, bulk density, and understory temperature—along with tree-layer characteristics—including canopy closure, tree species richness, and diameter at breast height (DBH)—on the species composition, functional traits, and phylogenetic structure of the shrub layer. Results showed: One-way ANOVA revealed significant differences in functional traits between the two forest types. Specifically, leaf thickness, specific leaf area, and chlorophyll content were significantly higher in the coniferous forest, whereas leaf dry matter content was significantly lower compared to the broadleaved forest (p < 0.05). These results suggest that understory shrubs in the coniferous forest primarily adopt a resource-conservative strategy, while those in the broadleaved forest exhibit a resource-acquisitive strategy. Phylogenetic analysis further revealed that the phylogenetic diversity (PD) of coniferous forests was significantly lower than that of broadleaved forests (p < 0.05). The phylogenetic structure in coniferous forests showed a more clustered pattern (NTI > 0, NRI > 0), suggesting stronger environmental filtering. Diversity index analysis showed that the Chao1 index indicated a richer potential species pool in broadleaved forests (p < 0.05), while species distribution was more even in coniferous forests (p < 0.05). Random Forest model analysis identified the diameter at breast height (DBH) of trees as the most critical negative driver, while soil pH was the primary positive driver. Redundancy Analysis (RDA) confirmed that the community structure in coniferous forests was mainly driven by biotic competition pressure represented by DBH, whereas the structure in broadleaved forests was more closely associated with abiotic factors like soil total nitrogen and pH (R² = 0.29, p < 0.05). These environmental drivers, through strong environmental filtering, collectively resulted in a phylogenetically clustered pattern of shrub communities in both forest types. This study demonstrates that the assembly of understory shrub communities is a complex, multi-level process co-regulated by multiple factors, shaped by both the biotic pressure from the overstory structure and abiotic filtering from the soil environment. This finding deepens our understanding of the rules governing community assembly in forest ecosystems. Full article

Alpine tundra’s harsh conditions challenge plants, but Rhododendron’s adaptive mechanisms remain unclear. This study explored phenotypic/transcriptomic adaptations of three Rhododendron species (R. aureum, R. lapponicum, R. redowskianum) in Changbai Mountains’ tundra vs. timberline. Mature leaves were sampled for leaf length and leaf width measurement and RNA-seq. Results showed leaf width (not leaf length uniformly) reduced in tundra across all species. RNA-seq identified 2399–5716 DEGs per species; plant dwarfism DEGs (e.g., DELLA, EDS1) were up-regulated. Shared DEGs were enriched in carbon/nitrogen metabolism and stress response; IPUT1 (DUH022406.1) and PGT1 (DUH001929.1) were consistently down-regulated (linked to dwarfism). Species-specific responses included R. aureum’s light adaptation, R. lapponicum’s freezing/hypoxia response, and R. redowskianum’s sugar/UV/microbial regulation. Rhododendron adapts to tundra via leaf width adjustment, metabolic optimization, and IPUT1/PGT1-mediated dwarfism, with conserved core mechanisms and species specialization, supporting climate change response predictions and conservation. Full article

Plants inhabiting arid regions often harbor microbial communities that contribute to their resilience under extreme conditions. Yet, the genomic diversity and functional potential of bacterial endophytes associated with desert-adapted plants, particularly in Africa, remain largely unexplored. In this study, we investigated Microbacterium endophytes from the xerophytic cucurbit Citrullus colocynthis L. (Cucurbitaceae), collected in a semi-arid environment in central Morocco. Using culture-based isolation, phenotypic characterization, and whole-genome sequencing, we analyzed three representative isolates from leaf and root tissues. Genome-based taxonomy combined with polyphasic analyses identified two novel species, Microbacterium xerophyticum sp. nov. and Microbacterium umsixpiens sp. nov., with genome sizes of approximately 4.0 Mb and 3.9 Mb, respectively. Functional annotation revealed traits consistent with endophytism in water-limited ecosystems, including oxidative and osmotic stress responses, metal homeostasis, and high-affinity phosphate uptake. Differences in siderophore acquisition and nitrogen metabolism suggest niche partitioning between the two species. These findings document two novel bacterial species from a medicinal plant native to arid ecosystems, broaden the known diversity of plant-associated Microbacterium, and provide region-specific genomic references with adaptive traits relevant to host resilience under arid conditions. Full article

Functional traits provide key insights into plant ecological strategies and responses to environmental heterogeneity, yet the role of intraspecific trait variability (ITV) in tropical rainforests remains underexplored. We examined ITV in six leaf traits—leaf thickness (LT), leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (LNC), and stomatal density (SD)—in saplings of 15 dominant tree species across ridge and valley habitats in a Sri Lankan tropical lowland rainforest. We compared interspecific and intraspecific variation and quantified trait plasticity using the plasticity index. Significant ITV was observed for LT, LA, and SD, with ridge individuals showing smaller, thicker leaves with lower SD. SLA, LDMC, and LNC exhibited no overall habitat-level differences, though species-specific divergent responses were detected. Interspecific variation exceeded ITV for most traits, except for LNC, where ITV accounted for 55% of total variation. Trait plasticity varied among traits, with LNC showing the highest plasticity. These results indicate that individuals adjust leaf traits in response to fine-scale habitat heterogeneity, reflecting shifts in resource-use strategies. Overall, ITV is ecologically meaningful and should be incorporated into community-level studies and ecosystem models to improve predictions of plant community dynamics and ecosystem functioning under environmental change. Full article

Rice ranks among the most significant staple crops worldwide. Precise and dynamic monitoring of specific leaf area (SLA) provides essential information for evaluating rice growth and yield. While previous remote sensing studies on SLA estimation have primarily focused on crops such as wheat and soybeans, studies on rice SLA remain limited. This study aims to evaluate the predictive potential of several machine learning algorithms for estimating rice SLA across different growth stages, planting densities, and nitrogen treatments at the pre-flowering stage. By utilizing UAV-based multispectral remote sensing data, a high-precision rice SLA monitoring model was developed. The feasibility of using vegetation indices (VIs), texture indices (TIs), and their combinations to predict rice SLA was explored. VIs and TIs were derived from UAV imagery, and the recursive feature elimination was conducted on these indices individually as well as their combined fusion (VIs + TIs). Four machine learning algorithms were employed to predict SLA values. The results indicate that random forest-based models utilizing VIs, TIs, and their fusion can all predict rice SLA effectively with high accuracy. Among these models, the RF model utilizing the combined variables (VIs + TIs) exhibited the highest performance, with R² = 0.9049, RMSE = 0.0694 m²/g, RRMSE = 0.1042, and RPD = 3.2419. This study demonstrates that individual VIs can provide effective spectral information for SLA estimation, especially during the crucial pre-flowering growth phase of rice. The fusion of VIs and TIs enhances the model’s adaptability to complex field conditions by integrating both canopy biochemical and structural characteristics, thus improving model stability. This technology offers a swift and efficient approach for monitoring crop growth in the field, offering a theoretical foundation for subsequent crop yield estimation. Full article

Mediterranean ecosystems are highly susceptible to wildfires, and shifts in fire patterns pose a threat to biodiversity, soil stability, and overall ecosystem health resilience. Implementing prescribed burning as a management strategy to lower wildfire risk has been proposed, but its ecological impacts in Greece are not well understood. This study examines the relationship between fireline intensity during prescribed burning and plant water potential, as well as its effects on soil properties and plant biodiversity on Chios Island, Greece. Field experiments were carried out in representative ecosystems, where we measured flame length to determine fireline intensity. In addition, we gathered soil samples before and after the prescribed burning and evaluated plant diversity. Measuring leaf water potential gave us a better understanding of how plants respond physiologically to different seasonal and site conditions. Our findings revealed that prescribed burning typically boosted plant diversity after the fire, with Fabaceae and Asteraceae playing a key role in regeneration. However, the soil responses differed from one site to another. Some sites saw a decline in organic carbon and nitrogen, while others showed an increase in exchangeable cations like calcium and magnesium, highlighting the importance of site-specific results. Studies on plant water potential revealed seasonal fluctuations in stress, underscoring the importance of accounting for seasonality in prescribed burn planning. Overall, prescribed burning has the potential to enhance biodiversity and ecosystem recovery, while also reducing fuel loads. These results highlight the importance of ongoing, site-specific monitoring for developing sustainable fire management strategies in Mediterranean ecosystems. Full article

Salinization and eutrophication are increasingly severe pollution problems in wetlands. Myriophyllum spicatum is a cosmopolitan species widely used for pollution control, but its physiological responses under combined stressors remain largely unknown. Here, we used mesocosms to investigate the ecophysiological responses of M. spicatum to three ammonia nitrogen concentrations (0, 1.5, and 3 mg L⁻¹) and two salt concentrations (0 and 5 g L⁻¹). Shoot and stem biomass were significantly affected by both salinity and nitrogen, whereas leaf phosphorus and stem nitrogen responded only to salinity (two-way ANOVA, p < 0.05). A significant salinity–nitrogen interaction was observed for stem biomass (p < 0.05); specifically, low nitrogen alone caused no significant reduction, but under saline conditions it markedly exacerbated biomass suppression. A significant salt–nitrogen interaction was detected for stem biomass (p < 0.05), such that low nitrogen alone did not significantly reduce stem biomass but exacerbated its suppression under saline conditions. These indicate potential synergistic environmental effects and suggest that even low nutrient inputs may aggravate stress under salt exposure. Stem biomass was significantly negatively correlated with malondialdehyde content (Pearson analysis, p < 0.05). Salt–nitrogen co-stress significantly increased malondialdehyde content (Tukey HSD test), indicating enhanced lipid peroxidation and associated oxidative damage, which may represent a physiological mechanism underlying growth inhibition in M. spicatum. Our findings demonstrate the complex adaptive responses of M. spicatum and emphasize the need to consider salt–nutrient interactions in conservation and restoration practices. Full article

Studying the response of plant leaf functional traits to elevation helps us understand plant adaptation to the environment and their distribution trends under global climate change. Currently, how plant leaf functional traits respond to elevation across different scales or among different species remains controversial. Quercus rehderiana Hand.-Mazz. is widely distributed across various altitude ranges in southwestern China, making it an ideal species to address this question. Therefore, this study established three 20 × 20 m quadrats at each of five altitude gradients (2000, 2200, 2400, 2600, and 2800 m). By measuring morphological and nutrient indicators in leaves from five individuals of Quercus rehderiana in each quadrat, we analyzed the response of leaf functional traits to elevation. The results showed that leaf thickness (LT), specific leaf area (SLA), phosphorus (P), potassium (K) concentrations, carbon phosphorus ratio (C:P ratio), and nitrogen phosphorus ratio (N:P ratio) of Quercus rehderiana varied significantly across different elevations. Regression analysis revealed that leaf area (LA), K concentration, and carbon nitrogen ratio (C:N ratio) decreased with increasing elevation, while LT and nitrogen (N) concentration increased. Correlation analysis indicated that LA was significantly negatively correlated with LT and leaf P concentration, but positively correlated with carbon (C) concentration and stoichiometric ratios (C:N, C:P, N:P). Leaf thickness (LT) was significantly negatively correlated with K and calcium (Ca) concentration. Specific leaf area (SLA) and K concentration were significantly negatively correlated with leaf dry matter content (LDMC). The leaves of Quercus rehderiana mainly adapt to different elevations through trade-offs among different morphological and chemical traits. These findings can support the conservation of germplasm resources and forest management. Full article

Phyllotaxy is a key determinant of intraspecific variation in leaf functional traits, with different leaflet positions often representing distinct strategies of resource acquisition and utilization. Yet, the extent to which such phyllotactic differentiation is modulated by ontogenetic stage remains poorly understood. Here, we examined saplings and adult trees of Fraxinus mandshurica, a dominant compound-leaved species in temperate broadleaf forests, by quantifying four leaf economic traits and four stomatal traits across six phyllotactic positions. We further assessed the relative influences of phyllotaxy and environmental factors, including soil total nitrogen, soil water content, and canopy openness, on trait variation at different ontogenetic stages. Our results showed that economic traits varied significantly along phyllotaxy, whereas stomatal traits were relatively conservative. The effects of ontogenetic stage on traits at a given phyllotactic position were trait-specific. Within-group correlations of economic traits and of stomatal traits remained stable across ontogenetic stages and were consistently stronger than between-group correlations. Sapling traits were more strongly affected by soil total nitrogen and soil water content, whereas those in adult trees were primarily shaped by soil water content and canopy openness. Moreover, both trait–trait and trait–environment associations were weaker at the leaflet level than at the compound-leaf level. Our study highlights the critical role of ontogenetic stage in shaping leaf trait responses to phyllotaxy and environmental change, providing new insights into the mechanisms underlying intraspecific trait variation in compound-leaved tree species. Full article

Understory vegetation, particularly dwarf bamboo, plays a crucial role in regulating forest nutrient cycles by intercepting litter and altering decomposition processes, yet its overall impacts remain understudied and insufficiently quantified. This study employs a combination of field surveys and decomposition bag experiments to investigate how understory dwarf bamboo (Fargesia decurvata) alters the spatial–temporal patterns of leaf litter production and decomposition. We found that the dwarf bamboo intercepted more than 25% of canopy litterfall, altering its spatial distribution and reducing decomposition efficiency in the bamboo crown (BC). Leaf trait-decomposition relationships differed strongly across habitats, being positive for saturated fresh weight (SFW), leaf thickness (LFT), and leaf area (LA) and dry weight (DW) in bamboo habitats but weaker in the bamboo-free habitat (NB). Potassium release was significantly higher in the BC treatment, whereas carbon release showed the opposite trend. In contrast, nitrogen and phosphorus exhibited net enrichment across all treatments, with phosphorus enrichment being slower in BC than in bamboo-covered ground surface (BG) and NB. Our results demonstrate that the understory dwarf bamboo reshapes the spatial distribution of litter and nutrient release dynamics during decomposition, resulting in element-specific nutrient release patterns. These findings provide mechanistic insights into how understory dwarf bamboo mediates nutrient cycling dynamics in forest communities. Full article

Organic fertilizer granulation represents a promising strategy for modifying nitrogen (N) release from compost in soil. Nevertheless, there is a lack of large-scale field trials exploring its impact on tobacco production and soil N supply. This research conducted a preliminary study by employing ¹⁵N tracing technology to investigate the effects of granular compost on soil N transformation and supply; on the yield and quality of tobacco leaves; and on the distribution of granular compost-derived N among the different soil N pools and tobacco plant organs. The results revealed that the 2 cm diameter granule organic fertilizer treatment (G2) significantly increased tobacco leaf yield by 15% compared to conventional fertilization (CK). However, the 4 cm diameter granule organic fertilizer (G4) treatment resulted in a reduction in leaf yield. Notably, the quality of tobacco leaves remained unaffected compared to conventional fertilization treatment; the N content ranged from 15 to 25 g kg⁻¹, which was within the high-quality range. The results also indicated that direct N supply to the tobacco from granular compost was limited. The G2 and G4 treatments provided 2.8% and 2.2% of the N in the fertilizer to the tobacco plants, respectively, with more than 93% of the N in the tobacco plants derived from the soil. Therefore, both of these particle sizes of granular compost facilitated the absorption of soil N by tobacco plants. At the end of the growth period, the N content derived from the G4 granular fertilizer in the soil was significantly higher than that from the G2 fertilizer. This may be due to the slower nutrient release mechanism and longer release period of the G4 fertilizer compared to G2. Our results suggested that granulated compost fertilizer (both G2 and G4) has the potential to enhance soil N supply. Despite the elevated nitrogen levels observed in leaves treated with 4 cm diameter granular fertilizer, an integrated assessment of yield performance demonstrates that the 2 cm diameter granular organic fertilizer delivers superior economic benefits. However, G2 may also have a higher potential for N loss. Further investigations under field conditions are necessary to validate the applicability of granular fertilizer of different particle sizes and its specific mechanisms of impact. Full article

The common bean (Phaseolus vulgaris L.) is a vital food crop worldwide, particularly in Latin America, Asia, and Sub-Saharan Africa, due to its high levels of protein, fiber, and essential nutrients. However, it is susceptible to viral infections, especially from the Bean common mosaic virus and Bean common mosaic necrosis virus. While previous research has primarily focused on specific resistance genes, a broader understanding of the plant’s overall immune response remains limited. To investigate this, a study was conducted involving 51 infected leaf samples. RNA was extracted, and deep metatranscriptomic sequencing was performed using the Illumina MiSeq platform. The results indicated that several genes related to stress response, nitrogen metabolism, and biosynthesis pathways were activated during infection. Key defense mechanisms included pathogen recognition, the production of antimicrobial peptides, and changes in metabolic activity. The Mitogen-Activated Protein Kinase (MAPK) signaling pathway and enzymes like glycosyl transferases, which aid in building protective structures, played a significant role. These findings suggest that the bean’s defense system is complex and involves not only direct attacks on pathogens but also metabolic shifts and microbial interactions. Understanding these processes provides valuable insights for breeding stronger, disease-resistant, and climate-resilient bean varieties. Full article

Horticultural research into the group of plants known as cycads has been deficient, and this includes the study of root growth and function. The form of nitrogen (N) available to plants is known to influence root growth and morphology. The response of cycad roots to N has not been studied to date. Cycas revoluta and Cycas edentata seedlings were grown in hydroponic culture and provided urea, nitrate, or ammonium forms of N. Solutions with all three forms of N increased root growth and branching when compared with nutrient solution devoid of N, with ammonium eliciting the greatest increases. Ammonium increased lateral root length 210% for C. revoluta and 164% for C. edentata. Ammonium decreased specific root length 38% for C. revoluta and 39% for C. edentata. The influence of the N source on stem and leaf growth was minimal. Ammonium increased the root-to-shoot ratio 15% for C. revoluta and 51% for C. edentata, but urea and nitrate did not influence this plant trait. A mixture of nitrate and ammonium generated plant responses that were no different from ammonium alone. The plants supplied with N in the solution produced coralloid root growth that was 14% of the no-N plants for C. revoluta and 22% of the no-N plants for C. edentata. This initial determination of the cycad plant response to the N form indicated that root plasticity was considerable and ammonium stimulated root growth more so than urea or nitrate. Long-term growth studies in mineral soils and nursery container medium are needed to determine if these findings from the hydroponic culture of small seedlings translate to general recommendations for the preferential use of ammonium for cycad culture. Full article