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Fusarium wilt disease of lettuce caused by the soilborne fungus Fusarium oxysporum f. sp. lactucae (Fola) causes substantial crop losses worldwide. Four races of Fola have been identified with race 1 (Fola1) and the more recently emerged race 4 (Fola4) predominant in Europe. Recent analysis of Fola1 and Fola4 genomes alongside PCR-based isolate profiling determined that while both Fola1 and Fola4 isolates harbour homologues of the putative effector genes Secreted in Xylem (SIX) 9 and SIX14, Fola4 has additionally gained SIX8, which is divergently transcribed with Pair with Six Eight 1 (PSE1) or Pair with Six Eight 1- Like (PSL1) genes. Transcriptomic analyses at a single timepoint also demonstrated high expression levels for SIX8, SIX9, SIX14 and PSL1 during Fola4 lettuce infection. In this study we demonstrate that SIX8, SIX9 and SIX14 expression levels increase up to 96 h following Fola4 lettuce infection, hence confirming their potential importance in wilt disease. The role of SIX8 in virulence on lettuce was then investigated through phenotyping of knockout mutants generated by CRISPR-Cas9 gene editing. ΔSIX8 mutants resulted in reduced disease in both in vitro lettuce seedling and pot-based lettuce plant glasshouse bioassays compared to wild-type Fola4. Complementation of SIX8 back into one of the knockout mutants using Agrobacterium-mediated transformation restored full virulence on lettuce. We conclude that SIX8 plays a role in Fola4 virulence and discuss the hypothesis that SIX8 may allow Fola4 to overcome some sources of Fola1 resistance and hence infect a different range of lettuce cultivars.

Lettuce (Lactuca sativa L.) is an important leafy vegetable with substantial diversity in leaf topology, geometry, color, and texture, which poses challenges for germplasm identification and new variety protection. However, current approaches to complex phenotypic analysis are often limited in their ability to explicitly represent and exploit semantic relationships among phenotypic traits. To address this limitation, a knowledge graph-enhanced graph learning framework for lettuce phenotypic traits was developed. Phenotypic traits were first extracted from leaf images of five lettuce types. Based on the trait description standards of the International Union for the Protection of New Varieties of Plants (UPOV), a Lettuce Leaf Phenotypic Trait Knowledge Graph (LLPT-KG) was constructed to represent semantic associations among traits. On this basis, a Dual-Channel Relational Graph Convolutional Network (DCR-GCN) was developed to jointly integrate node attribute features and graph structural information for lettuce type classification. To improve interpretability, node- and edge-level importance analyses were further performed to identify the phenotypic traits and semantic relations most relevant to type discrimination. The proposed framework achieved an accuracy of 0.94 and a Macro-F1 score of 0.94. Compared with the best-performing single-channel graph baseline, R-GCN (Relational Graph Convolutional Network), DCR-GCN improved accuracy by approximately 9% points and Macro-F1 by 10% points. These results demonstrate that combining knowledge graphs with graph neural networks can effectively capture complex phenotypic relationships in lettuce and improve classification performance. The proposed framework provides methodological support for precise lettuce germplasm identification, digital phenotypic evaluation for new variety protection, and digital-assisted pre-screening prior to field-based DUS (Distinctness, Uniformity, and Stability) testing.

Lettuce cultivation primarily involves two methods: traditional soil-based cultivation and modern hydroponic systems. However, research on the microbial community structure of lettuce under these distinct cultivation approache is still limited. This study employed whole-genome shotgun metagenomic sequencing (metagenomic sequencing) to analyze the impact of soil-based and hydroponic cultivation systems on the microbial community structure and functional profiles of lettuce. The microbial diversity index of soil samples was significantly higher than that of hydroponic samples, indicating a more diverse and complex microbial community in the soil environment. Key functional phylum, including Acidobacteriota and Actinomycetota, were more abundant in soil samples, supporting nutrient cycling and plant-microbe interactions through pathways involved in carbon metabolism, organic matter decomposition, and antibiotic biosynthesis. In contrast, hydroponic samples were dominated by Cyanobacteriota and Verrucomicrobiota, with enrichment of pathways associated with stress response, including quorum sensing, ABC transporters, and oxidative phosphorylation. Although α-diversity did not differ significantly between cultivation systems, their microbial community composition and functional profiles were markedly distinct: soil-grown lettuce exhibited enrichment in sugar catabolism and synergistic prokaryotic metabolic functions, whereas hydroponic lettuce showed a predominance of energy metabolism and enrichment of viral-related pathways. Furthermore, differential distribution of antibiotic resistance genes underscores the role of environmental selective pressures in shaping microbial functional adaptations. This study demonstrates that different cultivation methods significantly influence the microbial community structure and function in lettuce. These findings provide a theoretical foundation for optimizing cultivation systems and offer scientific guidance for precisely modulating microbial functions to promote lettuce growth and health.

Foodborne illnesses caused by pathogenic microorganisms have been increasingly linked to the consumption of fresh produce. In recent years, leafy greens, such as fresh-cut lettuce and packaged salads, have been implicated in outbreaks involving Escherichia coli (E. coli) O157:H7 and Salmonella. Intense pulsed light (IPL) is a nonthermal technology for food surface decontamination. This study assessed IPL for decontaminating fresh-cut Romaine lettuce and its effects on product quality during 10 days of storage at 5°C. Abaxial side of lettuce pieces (3.5 × 3.5 cm) were inoculated with nalidixic acid-resistant (100 µg/mL) strains of Escherichia coli (ATCC 8739) and Salmonella Typhimurium (ATCC 14028) and then treated with IPL for 0 to 11.5 s (0 to 8 pulses). Significant maximum reductions of 4.03 and 4.47 log CFU/cm2 were achieved for E. coli and Salmonella, respectively. While IPL caused significant changes in color (L*, a*, b*) and browning index, no significant changes were observed in firmness and chlorophyll content. However, IPL significantly increased electrolyte leakage. Native spoilage microbiota (total mesophilic, yeast and mold, and psychrotrophic counts) increased similarly in IPL-treated and control samples. The IPL-treated leaves showed higher total sugar content. Overall, IPL treatment on Romaine lettuce effectively reduced pathogens and has the potential to be used as an effective decontamination method for improving microbial safety and preserving quality attributes. PRACTICAL APPLICATIONS: Leafy greens like Romaine lettuce have been contaminated with foodborne pathogens such as, E. coli and Salmonella, resulting in recalls, outbreaks, illnesses, and, in extreme cases, death. Nonthermal treatments are needed to maintain product quality and eliminate pathogens. Intense pulsed light has the potential to be used as a dry treatment method for fresh-cut lettuce. This technology can be incorporated into the production line during pre-wash and trimming steps prior to packaging to treat lettuce surface for potential E. coli and Salmonella contamination.

Nanoparticles (NPs) are becoming more commonly used in agricultural practices for cultivating plants under Controlled Environment Agriculture (CEA). The foliar application of copper oxide (CuO) NPs can enhance the production of bioactive compounds in lettuce without adversely affecting yield. However, there is a lack of data regarding the effects of NPs on plants under various lighting conditions, which is a crucial aspect of CEA. The study aims to find out how different lighting conditions can lead to Cu accumulation, to determine the effects of CuO NPs on lettuce growth, antioxidant potential and mineral elements, and to investigate the potential risk of these NPs' uptake to human health. Plants were grown in Ebb-type hydroponic systems with red-blue and white-red-blue LED lighting at daily light integral 8.64 and 14.4, sprayed with aqueous suspensions of CuO NPs (40 nm, 30 ppm). The influence was determined on lettuce growth, the enzymatic (GR, APX, CAT, SOD, MDHAR, DHAR) and non-enzymatic (TPC, DPPH, ABTS, FRAP) antioxidants, mineral elements and hazard quotients. Our study showed the synergistic effect of foliar application of CuO NPs and lighting on lettuce. We found that CuO NPs positively influenced lettuce growth and stimulated the antioxidant system, particularly the non-enzymatic components such as phenols, carotenoids, and total antioxidant capacity. This effect was enhanced under a broader wavelength range of white-red-blue light and with a higher daily light integral value of 14.4. The application of CuO NPs significantly increased the Cu content in lettuce. Importantly, the concentration of the used CuO NPs did not reach the limit of Cu ions dangerous to humans, as the calculated intake level remained below safe limits, but it is not determined how much of them remained in the form of NPs.

Microplastics are major environmental contaminants due to their persistence and durability. However, research on the combined effects of heavy metals (HMs) and MPs on soil fungi and plant health remains limited. This study investigates the HMs contaminated soils in Tongling, along with polystyrene microplastics (PS-MP) of different sizes (T1 = 106 μm, T2 = 50 μm, and T3 = 13 μm), on soil properties, fungal diversity (including AMF and pathogens), and the growth/ antioxidant activity of Allium fistulosum and Lactuca sativa under two planting methods. Results showed that MP size significantly influenced fungal composition and plant growth, with planting procedure and exposure time playing key roles. PS-MPs increased soil pH, TC, EC, SOM, Cd, and TP while reducing nitrogen, ammonia, and nitrate levels. Alpha diversity declined in rhizosphere soil and Lactuca sativa with the Chao1 index, for example, decreasing by approximately 22% under the smallest MPs treatment in lettuce rhizosphere (T3R) compared to its bulk soil control (LCB). The phylum Blastocladiomycota was absent in T3-treated lettuce. Rhizosphere soils with smaller PS-MPs had a higher concentration of plant pathogens, particularly in lettuce. AMF were more abundant in bulk soil; smaller MPs reduced their abundance, especially in lettuce. Claroideoglomeraceae family was absent in lettuce but present in onion, while the Glomeraceae was highly sensitive to smaller MPs in rhizosphere soil. Growth parameters, membrane leakage, relative water content, and antioxidant activity were significantly affected, especially under T3 conditions. The combination of PS-MPs and HMs had a more severe impact on Lactuca sativa (seeds) than on Allium fistulosum (seedlings). Planting method critically influenced plant resilience and fungal community. Our results highlight the heightened ecological risks associated with small PS-MPs containing HMs, particularly for direct-seeded plants.

Returning spent mushroom substrate (SMS) to the field is an effective way to dispose of it. However, given the substantial nutrient consumption associated with Volvariella volvacea SMS, their effects on soil properties and crop performance warrant further investigation. By analyzing the effects of three different application rates of SMS on soil nutrients and lettuce (Lactuca sativa L.) quality, the results showed that the group with 1.5 kg m-2 SMS addition improved the total nitrogen (+21.2%), and organic content (+27.9%) in soil, and it demonstrated particularly outstanding performance in enhancing the survival rate (+21.9%), average weight (+71.7%), chlorophyll content (+45.6%), and total phenolic content (+25.2%) of lettuce. By comparing the soil microbial communities in the control group, the SMS (1.5 kg m-2) treatment group, and the organic fertilizer treatment group, it was found that they were mainly composed of Group S1, S2, and S3 microorganisms, respectively. The microbial community evenness in the treatment groups was greater than that in the control group. Furthermore, the results also revealed that the microbial conversion efficiency of nitrogen and phosphorus in the SMS treatment group was higher than the control group, which promoted nutrient cycling and improved the quality of lettuce. Our analysis provides an environmentally friendly way for Volvariella volvacea SMS disposal.

Real-time monitoring of H2O2 in plant tissues is useful for evaluating oxidative changes during postharvest storage, but direct on-site detection in vegetables remains difficult because most assays still require tissue disruption and laboratory instruments. In this study, a dual-signal microneedle biosensor was developed by integrating polydopamine-coated Fe/Zr-MOF nanozyme (PDA@Fe/Zr-MOF) into a gelatin/sodium alginate microneedle patch for H2O2 detection in lettuce. The polydopamine coating improved the peroxidase-like response of Fe/Zr-MOF through •OH generation and also contributed to photothermal conversion under 808 nm near-infrared (NIR) irradiation. After contact with lettuce leaves, the microneedles extracted interstitial fluid and allowed H2O2-triggered TMB oxidation to be read by both colorimetric imaging and thermal imaging. The two outputs were not independent recognition mechanisms, but they provided mutually supportive information and helped reduce the influence of sample color and environmental fluctuations. The sensor achieved detection limits of 0.42 μM for the colorimetric mode and 0.34 μM for the photothermal mode. During 15 days of storage at 4°C, the sensor tracked H2O2 accumulation in lettuce and showed a clear relationship with spoilage progression. These results indicate that PDA@Fe/Zr-MOF-based microneedle sensing is a feasible approach for monitoring oxidative freshness changes in postharvest vegetables.

Controlled Environment Agriculture (CEA) enables the cultivation of high-value crops under controlled environmental conditions, requiring precise nutrient monitoring to optimize fertigation. Standard practices to monitor plant nutrient status include nutrient leaf analysis (NLA), the reference method, but it does not reflect real-time status. Plant sap analysis offers real-time nutrient diagnostics; however, there is no standardized protocol for sap extraction methods across crops and individual nutrients. The objective of this study was to evaluate and compare multiple sap extraction methods for their reliability, practicality, and cost-effectiveness in diagnosing plant nutrient status in key CEA crops. Five sap extraction methods: ammonium acetate (AA), dry freezing (DF), extraction with ethyl ether (EE), extraction with potassium chloride (KCl), and tissue crushing (TC) were tested against NLA for assessing macro- and micronutrients in tomato (Solanum lycopersicum), cucumber (Cucumis sativus), and lettuce (Lactuca sativa) grown under CEA. For nitrate (NO₃⁻), KCL method was used as a reference and compared with EE and TC. The results indicated correlations between sap extraction methods and NLA were weak to moderate and varied across crops and nutrient types. The strongest correlations were obtained in lettuce using TC, with very high values for K (r = 0.99), Mg (r = 0.86), and Ca (r = 0.68). Other methods often yielded weak or negative correlations (e.g., tomato Ca with AA: r = - 0.36; cucumber Mg with KCl: r = - 0.15; lettuce Zn with EE: r = - 0.50). Sap NO₃⁻ correlations were variable, ranging from weakly positive (cucumber EE vs. KCl: r = 0.26) to negative (tomato TC vs. KCl: r = - 0.38), underscoring the complexity of NO₃⁻ dynamics and their dependence on crop physiology and developmental stage. A cost analysis showed that TC was the most affordable option, although it only worked for certain crops. These results indicate that, whereas some sap methods of extraction can produce indicative evidence of plant nutrient status in certain crops, none can accurately serve as a direct substitute for NLA.

High temperatures accelerate bolting and shorten the vegetative phase, thereby reducing the marketable yield in lettuce(Lactuca sativa L.). Using the KNOU lettuce core collection (KLC; n = 288), which represents major horticultural types, we integrated genome-wide association studies (GWAS) with genotyping-by-target-sequencing (GBTS), a multiplex target amplicon sequencing approach, to develop compact SNP marker panels for breeding-relevant prediction of reproductive timing. The KLC was genotyped via genotyping-by-sequencing (GBS; 97,528 SNPs) and phenotyped across two spring-to-summer seasons to analyze cumulative temperature to bolting (CTTB) and cumulative temperature to anthesis (CTTA) under protected cultivation conditions, revealing broad variation and high heritability (H = 0.79 and 0.74, respectively). Multi-model GWAS consistently identified a major hotspot on chromosome 7 for both traits, whereas additional loci showed trait- and year-specific effects. A lead SNP on chromosome 7 was validated by KASP, confirming a consistent allelic effect across genetic backgrounds. GWAS-supported loci were converted into compact GBTS panels (CTTB-only, CTTA-only, and pooled), and their ability to predict genomic estimated breeding values (GEBVs) was evaluated via repeated 5-fold cross-validation. The pooled panel achieved the highest predictive performance for CTTB (up to R2 = 0.41 with random forest and R2 = 0.37 with RR-BLUP), outperforming the CTTB-only panel. In contrast, CTTA prediction was more moderate (up to R2 = 0.32). Overall, this GWAS-to-GBTS panel strategy provides a practical basis for low-cost, early selection of reproductive timing in lettuce breeding.

Heavy metal cadmium (Cd) pollution poses a serious threat to agricultural safety, and the application of selenium (Se) to mitigate Cd stress introduces additional complexity for Cd nondestructive detection. This study investigated the feasibility of employing fluorescence hyperspectral imaging (F-HSI) for detecting Cd pollution in lettuce leaves under Se influence. The raw spectra were preprocessed using savitzky-golay filter to effectively suppress noise and enhance subtle spectral features, thereby highlighting weak fluorescence spectral information. Subsequently, a multi-modal differential fusion selector (M2DFS) was proposed to extract sensitive features closely associated with Cd by sorting out the complex fluorescence spectra-Se-Cd relationships under SeCd interaction conditions. Combined with a one-dimensional convolutional neural network (1D-CNN) based on the VGG architecture, the quantitative prediction model for Cd content in lettuce leaves under the background of SeCd interaction was developed. Compared with classical methods, M2DFS demonstrated superior feature extraction performance in both machine learning and deep learning models, significantly enhanced the predictive capability of Cd content under Se influence. Ultimately, the 1D-CNN model built using M2DFS-features achieved the highest prediction performance (Rp = 0.9173, RMSEP = 0.0272 mg/kg, RPD = 2.5108). In summary, the method system of F-HSI combined with savitzky-golay filter, M2DFS and 1D-CNN provides a reliable approach for nondestructive detection of Cd pollution in lettuce leaves under Se influence, offering a foundation for future research on nondestructive detection of heavy metal under complex agronomic environments.

Heavy metal pollution, particularly cadmium (Cd), seriously threatens crop growth and health. Here, molybdenum-selenium carbon dots (MoSeCDs) were developed to mitigate Cd toxicity in lettuce, and their underlying mechanisms were systematically elucidated. The results demonstrate that MoSeCDs promote plant growth by protecting chloroplast structure and maintaining photosynthetic activity, while simultaneously activating plant hormone signaling to enhance root vigor and modulating cell wall components to strengthen Cd immobilization. Moreover, MoSeCDs regulate the expression of metal transporter genes, reducing Cd uptake and facilitating vacuolar sequestration, while activating the antioxidant system to alleviate oxidative damage. MoSeCDs treated lettuce significantly decreased Cd accumulation in roots and leaves by 30.8% and 62.7%, respectively, and also mitigated stress induced by Pb, Cu, and Al. This study reveals the multi-dimensional regulatory mechanisms of MoSeCDs in plant heavy metal detoxification, providing a theoretical basis and practical potential for developing effective strategies to protect crops from heavy metal stress.

Antimicrobial resistance (AMR) in agricultural systems poses a critical "One Health" challenge, impacting animal, environmental, and human health. However, the field-scale dynamics of antibiotics within the soil-plant continuum, and their combined effects with organic fertilizers in driving antibiotic resistance genes (ARGs), remain poorly resolved. Here, we applied a stable isotope tracing approach using fully 13C-labeled sulfamethoxazole (13C10-SMX) in a lettuce field to track antibiotic dynamics across the soil-plant continuum. The half-lives of newly introduced 13C10-SMX in the labeled antibiotic (LA) and combined organic fertilizer and labeled antibiotic (OF&LA) treatments were 34.66 and 24.76 days, respectively. Rhizosphere soils showed early accumulation, with root-to-leaf translocation factors ranging from 0.16 to 0.34. OF&LA treatment amplified the relative abundance of ARGs by up to 5.35-fold in soils and 2.38-fold in roots, sustaining broad ARG enrichment. Mobile genetic elements (MGEs) emerged as the strongest direct driver of ARGs (β = 0.88), while 13C10-SMX exerted stronger indirect effects on ARGs than fertilizer inputs. Notably, nine high-risk ARGs were detected in lettuce leaves despite negligible antibiotic residue levels. These findings provide direct field-scale evidence that antibiotics and organic fertilizers jointly contribute to AMR propagation, highlighting the urgent need for integrated management strategies to mitigate agricultural AMR risks at the human-animal-environment interface.

Microplastic (MP) contamination in agricultural soils poses a significant threat to crop productivity and food safety. Earthworms, functioning as key ecosystem engineers, may mitigate such stress. Using Europium (Eu)-labeled polystyrene (PS) microplastics, we quantified MP accumulation in lettuce (Lactuca sativa L., 1753) and evaluated the role of earthworms in mitigating PS-induced stress. We found that PS microplastics mainly accumulated in the roots and were subsequently translocated to the shoots, resulting in reduced biomass, impaired photosynthetic performance, and lower soluble sugar and protein contents. However, earthworm activity substantially mitigated these adverse effects, decreasing MP accumulation in roots and leaves by 15% and 5%, respectively, increasing chlorophyll content (SPAD value) by 43%, and restoring photosynthetic performance (103% increase in net photosynthetic rate). Consequently, root and leaf dry weights increased by 17% and 43% (P&#x202f;<&#x202f;0.05), respectively. Mechanistically, earthworms increased soil pH, reduced acidification, restored microbial diversity, and enhanced nutrient cycling. Partial least squares modeling further revealed that earthworms promoted lettuce growth primarily by improving soil physicochemical properties, reducing oxidative stress, and limiting MP uptake. Collectively, these findings identify earthworms as important and effective bioregulators that buffer MP stress through bioturbation, microbial regulation, and soil amelioration, providing a sustainable strategy for mitigating MP-induced stress and regulating MP bioavailability in agricultural soils.

Soil salinization limits global agriculture, threatening food security and impairing crop productivity on irrigated lands worldwide. Using hydroponic lettuce (Lactuca sativa L.) to exclude soil confounders, this study investigated the mechanism of FA-mediated salt tolerance in lettuce under NaCl stress. It further examined FA-induced lignin remodeling across NaCl salinity of 7 mS cm-1 with FA concentrations ranging from 0, 50, 100, 150, 200&#x202f;mg L-1. Transcriptomics, antioxidant profiling, and advanced structural analyses (2D-HSQC NMR, GPC, GC-MS, etc.) were combined to elucidate the interplay among lignin modification, redox homeostasis, and photosynthetic protection. The treatment cleaved &#x3b2;-O-4 linkages, oxidised S/G units, and reassembled them into 400-700&#x202f;Da FA-lignin hetero-conjugates. Concurrently, FA decreased ROS accumulation, stabilized chloroplast ultrastructure, increased thylakoid density and plastoglobuli, and, compared with salt-stressed controls, improved photosynthetic electron transport efficiency by 11&#x202f;%, biomass by 27&#x202f;%, and soluble sugars 3.9-fold (p&#x202f;<&#x202f;0.01). Transcriptomic analysis revealed that FA modulated the expression of genes associated with lignin synthesis, redox balance, and photosynthesis. FA significantly upregulated genes like CCT7 and CSLA9, enhancing cell cycle progression, cell wall synthesis, and photosynthetic efficiency, providing molecular evidence for FA-mediated physiological improvements. Excessive FA (200&#x202f;mg L-1) exerted inhibitory effects, confirming 150&#x202f;mg L-1 as the optimal dose. Based on these findings, we propose a "lignin remodelling-redox homeostasis-photosynthetic protection" model, wherein FA-mediated lignin modification reinforces xylem development and leaf cell wall stability, thereby enhancing salt tolerance and providing a precise dosage basis for saline vegetable production.

Arsenic (As) contamination in agricultural water and soil poses a growing threat to leafy vegetable safety, with lettuce being particularly vulnerable due to its high water content and direct consumption without processing. This study investigated the capacity of exogenous syringic acid (SyA) to mitigate As-induced toxicity in lettuce plants, integrating physiological, biochemical, and untargeted metabolomics approaches. Arsenic significantly reduced plant biomass (31% and 53% in fresh and dry weight), impaired stomatal conductance, and suppressed net CO2 assimilation. However, the SyA application, particularly at 10&#x2009;&#x3bc;M, significantly restored biomass, photosynthetic performance, and redox homeostasis under As stress. Notably, SyA enhanced antioxidant capacity, as reflected by elevated FRAP and CUPRAC activities and increased accumulation of the phenolic compounds. Untargeted metabolomics revealed that As exposure broadly reprogrammed secondary metabolism, including activation of the phenylpropanoid and shikimate pathways with notable accumulation of flavonoid glycosides and alkaloids, consistent with a shift toward oxidative defense. Conversely, SyA at 500&#x2009;&#x3bc;M exerted phytotoxic effects even under nonstress conditions, confirming a biphasic, concentration-dependent mode of action with a critical threshold between 250 and 500&#x2009;&#x3bc;M. The findings suggest that an optimized concentration of SyA can act as a metabolic modulator, fine-tuning the plant responses to As by boosting the antioxidant defense system.

Soil salinity and lead (Pb) toxicity severely degrade soil health and crop productivity in arid regions. This study investigated the combined use of deashed biochar (DAB) and compost (COM) to alleviate salinity stress (SS) and Pb stress (LS) in lettuce under greenhouse pot experiment where crop physiological traits, oxidative stress responses, and soil-plant nutrient interactions were analyzed. Co-application of DAB+COM increased total chlorophyll (32.29%), photosynthetic rate (18.49%), transpiration rate (17.82%), and stomatal conductance (55.24%) under SS, with comparable enhancements under LS. Moreover, stress-induced markers like electrolyte leakage, carotenoids, and proline contents declined by 21.83%, 28.76%, and 24.73% in SS, whilst at LS these contents dropped to 19.13%, 23.94%, and 24.56%, respectively. Antioxidant enzyme activities (catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, glutathione reductase) in roots and leaves were substantially reduced in DAB+COM treatment under both stresses. Pb accumulation decreased by 20.68% (roots) and 17.61% (leaves), whilst soil N, P, and K availability improved substantially under DAB+COM amendments. Overall, these results suggest that synergistic amendment of DAB+COM offers a sustainable approach to rehabilitate degraded soils and enhance crop resilience in arid agroecosystems. This study provides comprehensive evidence that the co-application of de-ashed biochar and compost synergistically enhances lettuce resilience to combined salinity and Pb stress by improving photosynthetic efficiency, restoring soil nutrients, and minimizing both oxidative damage and heavy metal uptake.

Phthalate esters (PAEs) are emerging atmospheric contaminants in facility agriculture, yet their foliar transformations and phytotoxic mechanisms remain unclear. We compared the uptake, translocation, metabolism, and physiological effects of dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in lettuce after foliar exposure. The more hydrophobic DEHP accumulated in cuticular wax and leaves and caused oxidative lipid damage, whereas DBP was weakly retained in wax, translocated more readily to roots, and elicited stronger antioxidant responses. Both compounds were converted to monoesters, which accumulated at higher concentrations than their parent PAEs. Metabolomics revealed that DBP specifically upregulated arginine metabolism, suggesting an enhanced defense, whereas DEHP was associated with glutathione metabolism and ABC transporter pathways, consistent with responses to membrane peroxidation. These findings show that PAE physicochemical properties govern their fate in plants and drive compound-specific metabolic disturbances with important implications for crop safety under atmospheric PAE pollution.

The long-term geological disposal of radioactive waste necessitates robust risk assessment models to accurately predict radionuclide transfer from contaminated growing media into the human food chain. Iodine-129 (129I) and the rhenium isotopes 186Re and 188Re are of significant regulatory concern due to their anionic mobility, environmental persistence, and high bioavailability. However, current risk assessment frameworks typically rely on the assumption of constant, concentration-independent transfer factors (TFs), a foundational premise that remains largely untested across gradients spanning trace levels to acute phytotoxicity. Through controlled greenhouse experiments, we quantified the concentration-dependent uptake and physiological responses of iodine (0, 50, 100, 200&#xa0;mg&#xa0;kg-1) and rhenium (0, 5, 10, 20&#xa0;mg&#xa0;kg-1) in lettuce (Lactuca sativa L.). Iodine reached a lethal threshold at 200&#xa0;mg&#xa0;kg-1 (EC50: 58.9&#xa0;mg&#xa0;kg-1), following a classical monotonic response. Conversely, rhenium exhibited significantly higher phytotoxic potency (EC50: 19.7&#xa0;mg&#xa0;kg-1) and a distinct biphasic hormetic response. Concentrations of 5-10&#xa0;mg&#xa0;kg-1 stimulated shoot biomass and canopy density, whereas 20&#xa0;mg&#xa0;kg-1 induced severe growth suppression. Crucially, TFs for both elements were concentration-dependent, indicating that the constant-TF assumption does not hold under the present conditions. Rhenium demonstrated exceptional mobility with shoot-to-root ratios of 22-52, indicating rapid translocation to edible tissues. In addition, a scenario-based radiological assessment using literature-reported 129I soil activities indicated low screening-level ingestion doses under the modeled conditions. These findings provide vital empirical parameters for refining predictive environmental models and establishing evidence-based soil screening levels supporting human health and radiological risk assessment of radionuclide transfer through crop systems.