Search Results (314)

Walnut multiplication technology for obtaining high-quality planting material consists of grafting, followed by forcing bionts in protected spaces under controlled microclimatic conditions, and completed by acclimatization under field conditions. The present research substantiates the hypothesis that the use of protected spaces (polyethylene tunnels) enables rigorous control of limiting factors. The main objectives of the paper are the comparative evaluation of two grafting methods (chip and patch budding) on the grafting success of eight native genotypes (‘Anica’, ‘Grădinar’, ‘Miroslava’, and ‘Velnița’, ‘Bălțăți’, ‘Belcești’, ‘Săbăuani’, and ‘Șorogari’) grafted on ‘Bălțați’ local biotype, determining the optimal moment of grafting by identifying the time window (April vs. August) that maximizes the success rate of the grafting association. The study, carried out from 2022 to 2024, evaluated the performance of chip and patch budding executed under high-tunnel conditions, quantifying the scion/rootstock growth, callus formation, and anatomical symbiont similarity through cross-sectional microscopy and image analysis software to measure vessel number, density, and diameter; the results are presented as the mean values of three annual repetitions across the experimental period. Preliminary results indicate a superior efficiency of the chip budding method, with a 51.3% success rate compared to 32.9% for the patch budding method. Another objective of the study was the ranking of the experimental variants. Thus, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), a multi-criteria decision analysis method, ranked the experimental variants and identified the chip budding performed in April (variant a1/b2) as the optimal solution across all analyzed physiological and morphological parameters. These findings are highly significant for the nursery sector, as they demonstrate that transitioning from unpredictable field conditions to controlled high-tunnel conditions stabilizes production outcomes. By establishing a clear methodological hierarchy and a precise chronological window, this study provides actionable guidelines to standardize walnut multiplication, mitigate seasonal climate risks, and substantially increase the output of high-quality certified planting material. Full article

During the harvest period, the role of lateral leaves in the dynamic behavior of the walnut (Juglans regia) branch–leaf–fruit subsystem remains unclear, and vibration harvesting parameter selection still lacks targeted guidance. To address this issue, a local walnut branch–leaf–fruit subsystem was studied by combining a discrete dynamic model, free-vibration tests, forced-vibration tests, and MATLAB simulations to investigate the effects of lateral leaf number on system dynamics. A representative single-fruit subsystem with six lateral leaves was selected, and four leaf number conditions (zero, two, four, and six) were examined. High-speed imaging was used to identify leaf motion patterns, while natural frequencies and fruit tracking point displacement responses were measured. The results showed that lateral leaves mainly exhibited three motion modes during vibration: spin, swing, and spin–swing compound motion. Under the six-leaf condition, spin motion was dominant. As the number of lateral leaves increased from 0 to 6, the first-order natural frequency decreased from 13.92 ± 6.37 Hz to 8.79 ± 4.03 Hz, a reduction of 36.8%. Forced-vibration results showed that increasing lateral leaf number significantly reduced the displacement response of the fruit tracking point in the non-excitation directions. Under the six-leaf condition, the maximum displacements in the Y- and Z-directions were reduced by 56.0% and 55.8%, respectively, compared with the leafless condition, indicating that the forced response became more concentrated in the main excitation direction. In the original MATLAB model, lateral leaves were simplified as fixed lumped mass damping elements, and the predicted results differed from the experimental trends. After introducing dynamic damping parameters matched to leaf motion patterns, the simulated trends became closer to the experimental results. These findings indicate that lateral leaf number is an important structural factor affecting the natural characteristics and directional forced responses of the walnut branch–leaf–fruit subsystem. The results provide theoretical and experimental references for optimizing vibration parameters and supporting low-damage, high-efficiency walnut vibration harvesting. Full article

The aqueous extract of Diaphragma Juglandis Fructus (AED), a by-product of Juglans regia L., represents a promising food-derived functional ingredient with potential benefits for intestinal health. This study evaluated the anti-colitis effects of AED and explored its underlying mechanisms using LPS-stimulated RAW264.7 macrophages and a DSS-induced colitis mouse model. In DSS-induced colitis in mice, AED at 10 μg/mL suppressed pro-inflammatory cytokine production and inhibited JAK1/STAT3 signaling. In DSS-induced colitis in mice, AED at 600 mg/kg for 7 days mitigated DSS-induced colonic injury, restored tight junction proteins, and improved epithelial barrier integrity. Integrated transcriptomic and metabolomic analyses identified AED-associated alterations in arginine-polyamine and taurine-hypotaurine metabolism, while network pharmacology and molecular docking suggested angiotensin-converting enzyme (ACE) and von Willebrand factor (VWF) as candidate functional targets for further investigation. Collectively, these findings indicate that AED exerts anti-colitis effects in association with coordinated changes in inflammatory signaling, metabolic pathways, and barrier-related markers, supporting its potential as a food-derived functional ingredient candidate for ulcerative colitis management. Full article

(1) The growing interest in the use of natural and sustainable ingredients highlights the investigation of vegetable oils in dermato-cosmetic applications. In this context, the vegetable oil obtained from walnut (Juglans regia L.) is of actual interest due to its composition rich in unsaturated fatty acids. The aim of the present study was to investigate and characterize walnut oil from a physicochemical, structural, and rheological point of view. (2) The oil was obtained by a cold pressing process from walnut seeds, with a yield of about 51.03 ± 1.41%, and subsequently analyzed by complementary methods. (3) The results show an acceptable physicochemical profile, characterized by appropriate values of density, pH, and spreadability. The oxidative stability indicated a moderate resistance to degradation, specific to oils rich in polyunsaturated fatty acids. Fourier infrared transform spectrometry (FTIR) analysis confirmed the presence of functional groups characteristic of triglycerides, without indications of advanced oxidation, and atomic force microscopy (AFM) investigations revealed a heterogeneous morphology. The rheological properties indicated a pseudoplastic behavior, favorable for topical application. The determination of heavy metals confirmed the safety of the raw material for the intended dermato-cosmetic use. While arsenic levels were slightly above the strict Codex Alimentarius limits for foodstuffs, all values remained within the safety ranges established for cosmetic ingredients. A total of six fatty acids were found in cold-pressed walnut oil, determined using GC-MS methods. The number of compounds identified in the silylated sample was found to be 17. The antioxidant activity determined using DPPH and ABTS methods was generally considered good and relatively stable over time. The measured sun protection value (SPF) demonstrates a favorable capacity to act as a photoprotective ingredient against ultraviolet (UV) radiation. (4) Overall, the results demonstrate that walnut oil presents adequate physicochemical and structural properties, supporting its further use as a potential cosmetic raw material. Full article

Pyrolysis liquid (PL) derived from biomass pyrolysis exhibits biopesticidal properties and represents a promising value-added product within the sustainable circular economy framework. However, knowledge about the antimicrobial potential of PLs produced from walnut residue at different pyrolysis temperatures remains limited. We investigated the chemical composition and antimicrobial activity of PLs obtained from agricultural walnut residue (Juglans regia L.) against selected plant pathogenic bacteria and fungi. PLs were produced at four temperature ranges: 200–300 °C (W-1), 300–400 °C (W-2), 400–500 °C (W-3), and 500–600 °C (W-4). Chemical characterization was performed using Gas chromatography–mass spectrometry (GC-MS), High-performance liquid chromatography (HPLC), and Inductively coupled plasma optical emission spectrometry (ICP-OES), with determination of total phenolic and flavonoid contents. Pyrolysis temperature significantly influenced the chemical profile and bioactive compound content of the PLs, with W-4 showing the highest total phenolic and flavonoid levels. Heavy metal analysis indicated minimal contamination in all samples. Antibacterial activity was observed in stock solutions, whereas diluted applications showed limited effects. The W-4 fraction showed the strongest antibacterial activity and exhibited MIC values of 12.50 µL/mL against Clavibacter michiganensis subsp. michiganensis, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. syringae, and 25.00 µL/mL against Erwinia amylovora. Antifungal activity differed markedly across temperature ranges, with W-3 and W-4 displaying superior activity against Fusarium oxysporum and Verticillium dahliae, achieving complete mycelial growth inhibition at 5%, compared to 10% for W-2 and 20% for W-1. Positive controls confirmed assay validity (ciprofloxacin for antibacterial assays and cycloheximide for antifungal assays), whereas negative controls showed no inhibitory effect. Overall, higher pyrolysis temperatures, particularly 400–600 °C, enhanced the antimicrobial potential of walnut residue-derived PLs, supporting their possible use as bio-based antifungal agents for sustainable crop protection. Full article

Walnut is an important nut with a rich nutritional profile and associated health benefits for the human body. B-box (BBX) proteins containing one or two BBX motifs play pivotal roles in plant growth and developmental processes; nevertheless, the functions of JrBBXs in walnut anthocyanin biosynthesis remain inadequately understood. In this study, 39 JrBBXs in red walnut ‘RW-1’ were identified, with phylogenetic analysis suggesting that they were divided into six classes based on the distribution of conserved domains and unevenly distributed on 14 chromosomes. Promoter analysis demonstrated that JrBBX promoters possessed an abundance of light responsiveness elements, ABA responsiveness elements, MYB binding sites and MYC binding sites. The transcriptome analysis results demonstrated that eight JrBBXs were differently expressed in normal green walnut ‘Zhonglin 1’ and red walnut ‘RW-1’ seed coats. Furthermore, qRT-PCR (quantitative real-time polymerase chain reaction) analysis showed that JrBBX3 exhibited lower expression during seed coat development in ‘RW-1’. Y1H (Yeast One-Hybrid) and LUC (dual-luciferase reporter) assays revealed that JrBBX3 directly inhibited the expression of JrUFGT5, considered a key anthocyanin biosynthesis structural gene in research. Subcellular localization analysis indicated both cytoplasmic and nuclear localization of JrBBX3. Transient overexpression of JrBBX3 in walnut leaves resulted in reduced JrUFGT5 expression and anthocyanin accumulation. Collectively, these findings revealed the negative regulation of JrBBX3 in red walnut anthocyanin biosynthesis, and provided a basis to further study the anthocyanin biosynthesis mechanism of red walnut. Full article

Walnut septum (WS), a major by-product of walnut processing, represents a promising source of bioactive compounds with potential antioxidant and antimicrobial properties. This study aimed to characterise the phytochemical composition of WS extracts from different habitat origins and evaluate their antimicrobial activity. Total amino acids were profiled by gas chromatography–mass spectrometry, while phenolic compounds were analysed using high-performance liquid chromatography. Both methods were evaluated according to ICH Q2 (R2) guidelines for analytical procedure validation. The results showed a complex composition of amino acids and polyphenols, including ellagic acid and quercitrin. However, it was clear that habitat variations in WS samples had a significant impact on the quantities and composition of phenolic compounds and total amino acids in WS extracts. Antimicrobial activity was assessed against Gram-positive and Gram-negative bacterial strains. Variations in antimicrobial efficacy were associated with differences in phenolic composition and content due to habitat differences in WS sample origins. Collectively, this study highlights the WS as a valuable agro-industrial by-product with potential applications as a natural source of antimicrobial compounds in food and pharmaceutical systems. Full article

Green husks, which are the fleshy pericarp of Juglans regia L. fruit, are an abundant yet under-utilized source of bioactive compounds. They are useful for plant defense and have potential for valorization to multiple commercial products. This study characterized total phenolic content (TPC) and individual phenolics in green husks of four Hungarian-bred cultivars (Milotai 10, Milotai intenzív, Milotai kései, Esterhazy kései) and one U.S. cultivar (Chandler). Phenolic compounds were extracted with aqueous organic solvents, quantified by HPLC-DAD and qualitatively identified by HPLC-MS. Linear mixed-effects models were used to assess the effects of cultivar, year, sampling time, and cumulative growing degree days (GDDs) on TPC and compound profiles. Mean TPC ranged from 34.9 to 57.2 mg GAE g⁻¹ DW, with significantly higher values in the warmest year, 2024, and in cultivar Esterhazy kései compared with Chandler. Across cultivars and years, phenolic levels were generally elevated at early lignification (S1, BBCH 73–75) and at full maturity (S5–S6, BBCH 87–88), with depressed concentrations during mid-fruit development (S2–S4, BBCH 77–86). Several hydroxycinnamic acids, flavonoids, and naphthoquinones showed cultivar-specific and year-dependent patterns. Thermal conditions (cumulative GDDs) explained a substantial proportion of residual variation in TPC. These results highlight the combined roles of genotype, seasonal climate, and developmental stage dependencies in biosynthetic processes of phenolics in walnut green husks despite the diversity in factor effects. Full article

The study aimed to characterize the quality and evaluate the content of bioactive substances in cold-pressed pumpkin seed and walnut oils obtained from the specific varieties (Cucurbita pepo var. oleifera and Juglans regia L.). The analyses included the determination of acid value, peroxide value, and anisidine value. The content of chlorophylls and carotenoids was identified, and the fatty acid, phytosterol, and tocopherol profiles were characterized. The results were subjected to principal component analysis and compared with the physicochemical parameters of other popular niche oils. It was shown that both oils tested have unique, relatively simple fatty acid profiles (only 5–6 dominant acids were identified). In addition, significant differences in squalene content were observed: pumpkin seed oil showed a higher concentration than other vegetable oils. In contrast, walnut oil was found to lack squalene, which is atypical among the analyzed niche oils. Full article

The walnut cultivar ‘Yunxin No. 14’ is an early fruiting, high-yielding, and widely adaptable fruit tree with compact growth and superior nuts. Establishing a successful tissue culture system for this cultivar is crucial for its rapid clonal propagation and as a foundation for future genetic transformation. Using young fruits as explants, 3% NaClO sterilization for 20 min effectively controlled contamination and browning. Somatic embryos induced from zygotic embryos cultured on DKW medium with 30 g·L⁻¹ sucrose showed high proliferation and minimal browning. After a 4-day dehydration treatment using saturated NH₄NO₃, mature somatic embryos germinated rapidly on differentiation medium (DKW containing 1 mg·L⁻¹ 6-BA and 0.1 mg·L⁻¹ IBA), reaching 90.0% germination. Optimal shoot multiplication was achieved on DKW medium supplemented with 2 mg·L⁻¹ 6-BA and 0.3 mg·L⁻¹ IBA, yielding a proliferation rate of 91.1% and a proliferation index of 3.1. For rooting, shoots (~3 cm) treated with Clonex^® rooting gel were transferred to a low-cost, sugar-free vermiculite medium with gaseous CO₂ as the sole carbon source. Root initiation occurred within two weeks at a rate of 54.2%, significantly shortening the rooting phase. Rooted plantlets were acclimatized in a peat:perlite:vermiculite (2:2:1, v/v/v) mixture under high humidity for two weeks before outdoor transfer, achieving an 88.6% survival rate. This study provides a reliable protocol for the micropropagation of ‘Yunxin No. 14’ and a valuable reference for other difficult-to-root woody species. Full article

Research is needed to improve walnut drying throughput and energy consumption in hulling plants, but current methods for sampling nuts in commercial drying bins and measuring nut moisture content limit the capacity to investigate the drying process thoroughly. A novel apparatus for obtaining walnut samples at multiple depths and locations in stadium drying bins and a novel rapid method for accurately determining walnut in-shell moisture content were developed. A second rapid moisture measurement method involving near-infrared light (NIR) was also investigated. The sampling apparatus consisted of three sampling columns installed in each walnut drying bin. Each column had gate valves at four elevations, admitting approximately 30 in-shell walnuts to rectangular buckets hanging on a cable just below each gate valve. To collect samples, the gates were opened and closed, the buckets were withdrawn, the nut samples were collected and sealed in labeled bags, and then the buckets were returned to the column to be ready for the next sampling interval. This configuration, sampling nuts at four levels across three locations in the drying bin, allowed better moisture content variability investigation during in-bin walnut drying. The rapid moisture content measurement method consisted of selecting twelve representative in-shell walnuts from each sample and grinding them in a mill. Twelve grams were sub-sampled from the well-mixed ground material and dried in an oven at 105 ± 1 °C for 3 h, then reweighed to determine moisture loss. The coefficient of variation for sub-samples within an individual sample (n = 4) averaged 2.65% for moisture contents ranging from 6% to 47% dry basis. The rapid moisture content measurement method reduced the drying time from 24 h to 3 h compared to conventional oven drying method, with an accuracy of ±0.5 to 1.5% of the full moisture content range. The best correlation observed between the NIR methodology and the rapid moisture content method was 0.74 R². These new in-bin walnut sampling and moisture-content measurement methods will accelerate future research aimed at improving walnut drying at commercial huller facilities. Full article

Walnut (Juglans regia) is an economically significant woody oil tree species widely cultivated in China. However, its production is increasingly threatened by extreme low-temperature events, such as unseasonal frosts and late-spring cold. Salicylic acid (SA) is a key phytohormone known to enhance cold tolerance in plants, yet its underlying mechanism in walnut remains unclear. In this study, we present the first integrated analysis combining physiological measurements, transcriptomics, and metabolomics to investigate how exogenous SA improves cold tolerance in walnut leaves. Our results showed that SA treatment significantly increased the accumulation of soluble sugars, chlorophyll, and proline, enhanced peroxidase (POD) activity, and reduced malondialdehyde (MDA) levels under cold stress. Multi-omics analysis revealed that SA modulated the expression of genes involved in multiple hormone signaling pathways, including those of SA, auxin, jasmonic acid, and abscisic acid, and altered corresponding hormone levels. Notably, carbohydrate metabolism emerged as a central pathway mediating SA-induced cold adaptation. Weighted gene co-expression network analysis (WGCNA) further identified several core candidate genes, such as JrTGA, JrPP2C, JrTPS, and JrBAM, which may play key roles in this process. Collectively, this study provides the first multi-omics perspective on the regulatory network underlying SA-enhanced cold tolerance in walnut. These findings offer both a theoretical and technical foundation for applying SA in cold-resistant walnut cultivation and contribute to the development of stress-resilient production strategies. Full article

Objectives: This experiment was conducted to investigate the effects of adding walnut (Juglans regia L.) green husk (WGH) on the quality of alfalfa mixed silage, protein degradation, microbial community, and their interrelationships. Methods: Alfalfa (Medicago sativa L.) fresh grass and WGH dried powder were used as raw materials to prepare three mixed silages of alfalfa fresh grass with 80 g/kg (A1), 120 g/kg (A2), and 160 g/kg (A3) of WGH dried powder, respectively, with alfalfa fresh grass silage as the control group (CK). After 60 days of ensilage, samples were taken and analyzed, with three replicates per treatment. Results: WGH treatment significantly improved alfalfa silage fermentation and nutritional quality. It reduced undesirable fermentation products while promoting beneficial lactic acid bacteria and preventing mold growth. Increasing the WGH ratio enhanced dry matter content and digestibility, with only a minor effect on crude protein. These results suggest that WGH is an effective silage additive for improving both fermentation characteristics and feed value. With the increase in the proportion of WGH, the proportions of rapidly degradable protein (PB1) and medium rate degradable protein (PB2) increased linearly, while the proportions of free amino acid nitrogen (FAA-N), peptide nitrogen (Peptide-N), slow degradable protein (PB3) and binding protein (PC) decreased linearly and the protease activity decreased significantly (p < 0.05). Bacterial community analysis showed that the relative abundance of Lactiplantibacillus and Levilactobacillus in the silage increased after WGH was added, while the relative abundance of Acetobacter, Pantoea, Weissella and Serratia decreased. Conclusions: Compared with pure alfalfa silage, the addition of WGH has a positive effect on silage quality, protein degradation and bacterial community structure, and the addition of WGH with 120 g/kg is more suitable. Full article

Walnut is valued for being rich in nutrients and polyphenols, which are key bioactive metabolites; however, a comprehensive and dynamic assessment of metabolites in the husk and pellicle is still lacking. In this study, multi-omics approaches combining untargeted metabolomics and transcriptome analysis were conducted to systematically characterize the differential metabolite profile and regulatory networks in walnut husk and pellicle. Metabolomic profiling revealed a clear divergence in polyphenol compositions between the husk and the pellicle; the husk was predominantly enriched in nine phenolic acid compounds, whereas the pellicle accumulated eleven flavonoid compounds. Through co-expression network analysis, a transcription factor, JrMYB8, was identified and shown to act as a specific inhibitor and regulator of polyphenol biosynthesis. Functional characterization demonstrated that JrMYB8 overexpression significantly reduced the accumulation of the total phenol content (TPC) and the total flavonoid content (TFC) by directly repressing the expression of JrC4H. These findings not only provide a molecular target for manipulating polyphenol content in walnut tissues but also offer a target for improving flavor in walnut breeding. Full article