Search Results (1,499)

Internet of things long range (IoT/LoRa) devices emit radiofrequency electromagnetic fields (RF-EMF), ensuring long-range, low-power communication, and their use in precision agriculture continuously expands. Thus, the interest in the impact of low-intensity but long-term EMF exposure on plants has increased. In this study, maize plants were exposed to 868 MHz, 10 mW EMF for the first 28 days of their development with soil-buried antennas. Plants were divided into three groups: Control, Sham-exposed, and EMF-exposed. Biological effects were followed on morphological, physiological, and biochemical levels every week. The plant height values were fitted to a Gompertz function modeling the growth. The results showed slightly faster early development of EMF-exposed plants in about 21 days. The relative dry-leaf biomass from EMF-affected plants was a bit higher than in the Control and Sham groups until day 21. Chlorophyll fluorescence analysis (JIP-test) indicated photosynthetic stability. Antioxidant enzyme activity, antioxidant capacity, content of malondialdehyde, hydrogen peroxide, and reducing sugars were measured, and principal component analysis was done for all parameters. Overall, the developmental stage accounts for most of the observed variations in the data rather than EMF exposure. The results suggest that under the tested conditions, IoT/LoRa-emitted EMF did not provoke adverse effects in maize and acted as a modest modulator of physiological functions. Full article

A comprehensive multiregional characterization of the spectral response of cassava leaves across different ontogenetic stages was performed. For this, ultraviolet (UV), visible (VIS) and shortwave near-infrared (UV-VIS-NIR; 200–900 nm) regions were used to identify spectral signatures and indices for their potential use as biomarkers of leaf development and physiological status of plants under induced senescence conditions. Manihot esculenta Crantz (HMC-1 variety) was used as a model. Spectral signatures were obtained from leaves at two phenological stages (4 and 6 months after planting) using UV-VIS-NIR spectroscopy by the diffuse reflectance technique. Classical and experimental spectral indices were evaluated, and their discriminatory power through different ontogenies was assessed using ANOVA/Kruskal–Wallis and post hoc tests. Senescence effects were further examined by postharvest monitoring (1–20 days), with temporal, ontogenetic, and interaction effects validated using linear mixed models (LMMs), while multivariate structure and spectral convergence were explored via principal component analysis and hierarchical clustering (PCA-HCA). Functionally Enhanced Derivative Spectroscopy (FEDS), comparative analysis, and spectral correlation mapping allowed signal’s selective enhancement and the identification of phenolic compounds, photosynthetic pigments, and structural molecular components. Results showed high ontogenetic stability of UV-associated phenolic signals (~210–220 nm), whereas the VIS region (420–600 nm) clearly differentiated young leaves. The NIR region was stable across ontogeny but highly sensitive to temporal degradation, reflecting changes in water status and internal structure. UV-VIS-NIR indices effectively differentiated young leaves and changes by stress. It is concluded that multiregional characterization of the spectral response supported by FEDS allows the extraction of robust indices with strong potential as biomarkers of leaf maturation and senescence in cassava. Full article

Tropospheric ozone (O₃) is a phytotoxic air pollutant that can impair visible foliar injury (O₃ VFI) and reduce photosynthesis in sensitive forest species. Viburnum lantana L. has been used as an in situ bioindicator of O₃ pollution in mountainous areas of Europe; however, flux-based response functions and critical levels (CLs) for this species have not yet been established. This study validated field-observed O₃ effects in V. lantana through experiments carried out in a Free-air O₃ eXposure infrastructure and determined which O₃ metric (exposure-based AOT40 or flux-based-POD₁) best explains O₃ effects on leaf physiology and VFI. Throughout the experimental period (T2: 3.5-month O₃ exposure), V. lantana saplings were subjected to ambient air (AA) conditions and elevated O₃ levels (1.5× and 2.0× AA). O₃ VFI appeared after 16 days in 2.0× and increased progressively during the growing season, reaching the highest Plant Injury Index (PII) values in the 2.0× (9.06 ± 3.24) compared with 1.5× and AA treatments (1.31 ± 0.62 and 1.29 ± 0.71). Elevated O₃ also significantly reduced net photosynthetic rate (A_sat), relative chlorophyll content (SPAD), and the maximum photochemical efficiency of photosystem II (F_v/F_m); no significant difference in stomatal conductance (g_s) was found. The flux-based metric POD₁ better explained variability in O₃ VFI and physiological parameters. Based on the best-fitting models, CLs for V. lantana were estimated at 1.61 mmol m⁻² and 1.22 mmol m⁻² for a 4% reduction in A_sat and g_s, and a CL of 7.82 mmol m⁻² for the O₃ VFI-onset. Full article

The Kelch-repeat superfamily genes played important roles in regulating plant growth and development; however, their functions in foxtail millet (Setaria italica) have not yet been characterized. In this study, SiNL4, a homolog of ZmNL4 controlling leaf width in maize, was knocked out using the CRISPR/Cas9 technology, and two homozygous knockout lines (ko1 and ko2) were obtained. Phenotypic analysis showed that compared with the wild-type Ci846, ko1 and ko2 exhibited reduced leaf width and decreased yield related traits (e.g., panicle weight, grain width, and 1000-grain weight). Cytological analysis showed that changes in leaf width of ko1 and ko2 resulted from a decrease in leaf epidermal cell width and the number of small vascular bundles (SVBs) close to the leaf edge, suggesting that SiNL4 might regulate leaf width by influencing cell expansion and the development of SVB. Spatiotemporal expression analysis indicated that the relative expression level of SiNL4 was high in the stem, leaf, and young panicle. Subcellular localization showed that SiNL4 was mainly localized in the mitochondria and plasma membrane. In addition, the T-DNA insertion mutant (Atnl4) of AT5G18590, the ortholog of SiNL4 in Arabidopsis thaliana, exhibited similar phenotypes with reduced rosette leaf width, seed width, and 1000-seed weight. Moreover, complementary expression of SiNL4 in Atnl4 not only restored the phenotypes, but also significantly increased the 1000-seed weight, indicating that the function of these two genes might be conserved. Meanwhile, we found that SiNL4 knockout caused a decrease in chlorophyll content and net photosynthetic rate (Pn), showing that SiNL4 might be involved in regulating photosynthesis. In summary, this study revealed the function of SiNL4 in regulating leaf width in foxtail millet, providing a potential gene for the genetic improvement of foxtail millet. Full article

The growing use of wireless technology significantly increases the exposure of all living organisms to radiofrequency electromagnetic fields (RF-EMF). However, the physiological effects of RF-EMF on plants have not yet been sufficiently researched. In this study, we investigated the effects of RF-EMF radiation in the frequency ranges 1890–1900 MHz (DECT) and 2.4 GHz plus 5 GHz (Wi-Fi) on photosynthetic performance of Tilia plants (Tilia tomentosa). The recorded fast chlorophyll fluorescence transients were used to analyze the structure and function of PSII by the JIP-test. The analysis of the fluorescence of chlorophyll a showed that the RF-EMF interfered with the electron transport processes of photosynthesis. Tilia plants exposed to RF-EMF induced decrease in photosynthetic efficiency (F_V/F_M) and inactivation of part of PSII reaction centers (RC/CS_O). Observations of leaf senescence and lifespan over a period of 102 days showed that RF-EMF-exposed Tilia plants exhibited accelerated aging. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

Leaf biomass accumulation is a critical determinant of photosynthetic capacity and crop productivity. In Arabidopsis thaliana, multiple hormonal and environmental pathways, including brassinosteroid (BR), auxin and light signaling, as well as functional proteins such as TNY (TINY), SAUR21 (SMALL AUXIN UP-RNA21) and HY5 (ELONGATED HYPOCOTYL 5), play important roles in regulating leaf growth. However, the precise regulatory mechanisms integrating these factors during leaf biomass accumulation remain incompletely understood. Herein, we showed that NF-YC3/4/9, members of the NUCLEAR FACTOR Y subunit C family, were required for normal leaf cell expansion. Loss-of-function mutation of NF-YC3/4/9 (nf-ycT) resulted in significantly smaller true leaves with reduced leaf cell expansion. NF-YC9 directly regulated the expression of HY5, HYH, and SAUR21 and indirectly regulated the expression of TNY. These results help reveal the function of NF-YCs in leaf growth and provide insights into the regulation of hormonal and transcriptional networks controlling leaf biomass accumulation in A. thaliana. Full article

Extreme flooding has emerged as a major climate risk for low-lying Australian macadamia (Macadamia spp.) orchards, yet the physiological mechanisms underlying tree decline remain poorly understood. We investigated whole-plant responses to complete submergence in young, grafted macadamia trees by subjecting plants to one- and two-week floods, as well as repeated flooding. Following emergence from the flood water, photosynthetic rate (A) and stomatal conductance (g_s) declined progressively with increased flood duration and repeated exposure. Grafted plants of G on H2 maintained a more resilient photosynthetic apparatus post-flood than G grafted on Beaumont, as reflected by a smaller decline in maximum assimilation rates as well as biochemical capacities for ribulose 1,5 bisphosphate (RuBP) carboxylation (V_cmax), and RuBP regeneration (J_max). Despite these differences in leaf-level function, prolonged and repeated flooding triggered a cascade of post-flood stress symptoms in both rootstocks, including progressive canopy dieback, sharp reductions in root biomass, depletion of total non-structural carbohydrates, and ultimately scion mortality. Collectively, these findings indicate that plants only partially tolerated one week of complete submergence, whereas longer or repeated flooding severely compromised carbon balance and plant survival in both rootstocks. Full article

To reveal the variation patterns and differences in the adaptation strategies of leaf functional traits between male and female Populus euphratica in an arid desert environment, this study evaluated the effects of sex, developmental stage, and their interaction on 31 leaf traits using variance partitioning and trait network analysis. Furthermore, we analyzed the topological characteristics of the trait networks across two dimensions: developmental stage and vertical canopy gradient. The results indicated that sex moderately explained the variation in leaf nutrient characteristics (N and K) and physiological resistance indicators (Pro). Meanwhile, developmental stage largely accounted for variations in traits such as leaf dry weight, leaf width, specific leaf area, and photosynthetic physiology. The interaction between sex and developmental stage significantly influenced leaf anatomical structures and water-use strategies. Leaf trait network analysis revealed that during development, the male network exhibited higher connectivity and shorter average path lengths, with its core traits shifting from photosynthetic physiological indicators to nutrient and water transport characteristics; female plants exhibited higher network modularity during key developmental stages, with core nodes concentrated on leaf area, biomass, and structural traits. Along the vertical canopy gradient, the male leaf trait network showed pronounced topological reorganization in the mid-to-upper layers, suggesting a stronger capacity to respond to environmental fluctuations. Conversely, the core hubs of the female leaf trait network shifted from morphogenesis toward a synergy between structure and metabolism, which may be associated with maintaining system stability at different canopy heights. These findings suggest that female and male P. euphratica may adopt “conservative” and “acquisitive” ecological adaptation strategies, respectively, potentially leading to differentiated patterns of trait variation and coordination. This study provides a theoretical basis for understanding the potential ecological adaptation mechanisms and evolutionary strategies underlying sexual dimorphism in desert plants. Full article

Seaweed-derived biostimulants are a promising strategy for improving crop performance in sustainable agriculture. In this context, this study evaluated the effects of foliar application of Kappaphycus alvarezii extracts, obtained from two Brazilian regions (São Paulo: Kal-SP and Santa Catarina: Kal-SC), at different concentrations (1%, 3%, 5%, and 7%) on the growth, biochemical profile, essential oil yield, and rhizosphere microbiome of Ocimum basilicum under field conditions. Morphological analysis indicated that the 5% and 7% concentrations increased plant height, biomass, root development, and inflorescence production, with biomass gains of up to 51% and essential oil production increases of up to 142% compared to the control. Biochemical responses varied by extract origin, with Kal-SC promoting greater increases in photosynthetic pigments, antioxidant activity, and carbon-related metabolites, whereas Kal-SP induced only minor metabolic changes. The algal biostimulant modulated essential oil yield and composition, promoting treatment-dependent shifts in major terpenoid compounds. Microbiome analysis showed no significant changes in alpha diversity, but significant shifts in beta diversity and functional groups, such as Bacillaceae, indicating rhizosphere reorganization. Overall, the effectiveness of K. alvarezii-based biostimulants depends on concentration and biomass source, highlighting their potential as sustainable agricultural bioproducts and the importance of standardized extraction for consistent outcomes. Full article

Cadmium (Cd) is one of the most toxic heavy metals in the environment, and it severely represses photosynthesis, growth, development and nutrient uptake in photosynthetic organisms. Excessive cadmium (Cd) taken up by plants seriously threatens global food security and human health. Therefore, designing an eco-friendly and sustainable strategy that can reduce the accumulation of Cd in plants is a major challenge. Phosphorus (P), as an essential nutrient for plant growth, has been shown to play a pivotal role in mediating Cd-induced stress response. However, the molecular mechanisms underlying the crosstalk between phosphate signaling and Cd stress response remain largely uncharacterized, especially the role of the core phosphate homeostasis regulator Phosphate Starvation Response 1 (PSR1). Here, we used the model green microalga Chlamydomonas reinhardtii to investigate the physiological and transcriptomic responses to Cd stress in wild type (WT, CC-125) and PSR1 loss-of-function mutant (Crpsr1, CC-4267). Our results showed that the Crpsr1 mutant exhibited significantly enhanced Cd tolerance compared with WT under P-sufficient conditions, with a better growth phenotype and a significantly lower Cd accumulation. Transcriptome analysis revealed distinct gene expression profiles between WT and the Crpsr1 mutant in response to Cd treatment. Gene Ontology (GO) enrichment analysis showed that differentially expressed genes (DEGs) were mainly involved in primary metabolism, protein kinase activity, ion binding and transmembrane transport, which are critical processes for mitigating Cd stress. Notably, key genes associated with iron uptake and homeostasis were significantly upregulated in the Crpsr1 mutant under Cd stress, indicating a potential regulatory link between PSR1, iron homeostasis and Cd tolerance. Taken together, our findings establish a functional association between the central phosphate signaling regulator PSR1 and Cd stress response in green microalgae, and provide novel candidate genes and regulatory networks for developing engineered microalgae with enhanced Cd phytoremediation capacity. Full article

Aluminum (Al) toxicity is an important factor limiting crop production in acidic soils; however, systematic evaluation of Al tolerance and its physiological basis in celery (Apium graveolens L.) remains limited. In this study, 400 μmol·L⁻¹ AlCl₃ was identified as the appropriate concentration for Al-tolerance screening through a concentration-gradient experiment. Based on this concentration, 43 celery germplasm accessions were evaluated using 14 morphological and physiological traits. A comprehensive evaluation framework for Al tolerance was established using principal component analysis, membership function analysis, and hierarchical cluster analysis. The comprehensive A-value index enabled quantitative evaluation and classification of Al tolerance, and the accessions were divided into five categories ranging from highly Al-tolerant to highly Al-sensitive. Furthermore, key indicators were identified through stepwise regression analysis, which simplified the evaluation system while maintaining its assessment reliability. Physiological analysis of contrasting accessions showed that Al tolerance in celery was closely associated with restricted Al accumulation, enhanced redox homeostasis, and maintenance of photosynthetic system stability. Among these processes, the coordinated regulation of antioxidant defense and light energy utilization efficiency may represent an important physiological basis for tolerance differentiation. Overall, this study established an integrated framework from screening-concentration optimization to comprehensive evaluation and physiological characterization, providing a technical reference for the screening, evaluation, and breeding utilization of Al-tolerant celery germplasm. Full article

Objectives: Plant extracellular vesicles (EVs) mediate intercellular communication and carry tissue-specific metabolites, yet tissue-resolved EV metabolomics in non-model medicinal plants remains poorly explored. Hibiscus syriacus is a valuable medicinal and ornamental species rich in bioactive compounds, but the metabolic profiles of flower- and leaf-derived EVs are unknown. This study aimed to characterize tissue-specific EV metabolomes of H. syriacus and reveal their functional implications. Methods: EVs were isolated from flowers (MJH) and leaves (MJY) of H. syriacus and verified by TEM and DLS. Untargeted LC-MS/MS metabolomics was applied to profile EV metabolites. Multivariate statistics (PCA, OPLS-DA), differential metabolite screening (VIP > 1, p < 0.05), and KEGG pathway enrichment were performed. Results: MJH- and MJY-EVs exhibited typical EV morphology and high purity. In total, 3338 metabolites were identified, dominated by lipids (29.43%). Clear metabolic separation was observed between MJH- and MJY-EVs. Thirty-nine differential metabolites were identified: 31 upregulated in MJH-EVs (lipids, pentadecanoic acid) and eight in MJY-EVs (nucleotides, secondary metabolites). Glycerophospholipid metabolism was the most enriched pathway in MJH-EVs, while MJY-EVs were linked to energy and defensive metabolism. Conclusions: H. syriacus EVs display strong tissue-specific metabolic signatures. Leaf EVs prioritize lipid metabolism for photosynthetic function and stress tolerance, while flower EVs accumulate secondary and energy-related metabolites for reproduction and defense. These findings advance plant EV biology and support potential applications of H. syriacus EVs in cosmetics and agriculture. Full article

Global crop production faces serious threats from soil salinization. Microbial resources are often exploited to be used as fertilizers or seed coatings to address this issue. Parametarhizium changbaiense, as a novel beneficial microorganism, has been discovered to be capable of assisting limited crops such as mung bean in resisting salt–alkali stress. To investigate the effects of P. changbaiense on sugar beet under salt–alkali stress, the salt (NaCl:Na₂SO₄, molar ratio 9:1) and alkali (NaHCO₃:Na₂CO₃, molar ratio 9:1) stress were set on sugar beet germplasm 780016B. Results demonstrated that P. changbaiense improved the phenotypic characteristics of sugar beet seedlings under salt–alkali stress. The biomass parameters such as plant height and fresh weight significantly increased by growth-promoting effect. The elevated antioxidant enzyme activity could help protect plants from ROS damage induced by stress. Relative electrical conductivity and MDA content decreased with inoculation, thereby mitigating membrane lipid peroxidation and improving membrane system stability. The higher content of soluble sugar could maintain cell turgor pressure and alleviate osmotic stress. Inoculation with P. changbaiense enhanced chlorophyll content, fluorescence, and photosynthetic capacity. The more superior root vitality and architecture were suitable for the functions of metabolism and absorption. P. changbaiense could promote the growth and physiological characteristics under salt–alkali stress, so it has practical application value in agricultural production. Full article