Search Results (267)

Grafting involves complex hormonal interactions at graft interfaces that are not yet fully understood. In this study, we analyzed hormone fluctuations and gene expression during callus proliferation and vascular tissue differentiation in hickory (Carya cathayensis Sarg.) grafts. Cytokinin and ethylene precursor ACC levels steadily increased after grafting. The biosynthetic genes for these hormones (IPT3, ACS1, ACO1, and ACO5) exhibited heightened expression. Genes related to cytokinin signaling (RR3, ARR4, and ZFP5) and ethylene signaling (MKK9, ESE1, and ESE3) were similarly upregulated. Conversely, genes associated with jasmonic acid, abscisic acid, and strigolactone pathways were downregulated, including synthesis genes (AOC4 and AOS) and those involved in signal transduction (NAC3, WRKY51, and SMAX1). Correspondingly, JA-Ile and 5-deoxystrigol levels significantly decreased. Indole-3-acetic acid (IAA) levels also dropped during the early stages of graft union formation. These results suggest that low auxin concentrations may be essential in the initial stages after grafting to encourage callus proliferation, followed by an increase at later stages to facilitate vascular bundle differentiation. These findings imply that maintaining a balance between low auxin levels and elevated cytokinin and ethylene levels may be critical to support cell division and callus formation during the initial proliferation phase. Later, during the vascular differentiation phase, a gradual rise in auxin levels, accompanied by elevated ethylene, may facilitate the differentiation of vascular bundles in hickory grafts. Full article

Introduction: Scattering of kernels due to angular dehiscence is a key bottleneck in mechanized harvesting of oilseed rape. Materials and Methods: In this study, a dual-track “genotype–phenotype” screening strategy was established by innovatively integrating high-throughput KASP molecular marker technology and a standardized random collision phenotyping system for the complex quantitative trait of angular resistance. Results: Through the systematic evaluation of 634 oilseed rape hybrid progenies, it was found that the KASP marker S12.68, targeting the cleavage resistance locus (BnSHP1) on chromosome C9, achieved a 73.34% introgression rate (465/634), which was significantly higher than the traditional breeding efficiency (<40%). Phenotypic characterization screened seven excellent resources with cracking resistance index (SRI) > 0.6, of which four reached the high resistance standard (SRI > 0.8), including the core materials NR21/KL01 (SRI = 1.0) and YuYou342/KL01 (SRI = 0.97). Six breeding intermediate materials (44.7–48.7% oil content, mycosphaerella resistance MR grade or above) were created, combining high resistance to chipping and excellent agronomic traits. For the first time, it was found that local germplasm YuYou342 (non-KL01-derived line) was purely susceptible at the S12.68 locus (SRI = 0.86), but its angiosperm vascular bundles density was significantly increased by 37% compared with that of the susceptible material 0911 (p < 0.01); and the material 187308 (SRI = 0.78), although purely susceptible at S12.68, had a 2.8-fold downregulation in expression of the angiosperm-related gene, BnIND1, and a 2.8-fold downregulation of expression of the angiosperm-related gene, BnIND1. expression was significantly downregulated 2.8-fold (q < 0.05), indicating the existence of a novel resistance mechanism independent of the primary effector locus. Conclusions: The results of this research provide an efficient technical platform and breakthrough germplasm resources for oilseed rape crack angle resistance breeding, which is of great practical significance for promoting the whole mechanized production. Full article

Asian chestnut gall wasp (ACGW) (Dryocosmus kuriphilus Yasumatsu), native to China, is an invasive pest that causes significant economic losses in Castanea species. While some cultivars show full resistance by inhibiting insect development in buds, the underlying defense mechanisms remain unclear. In this study, the accumulation and distribution of hydrogen peroxide (H₂O₂) were investigated in dormant buds of chestnut cultivars that are resistant and susceptible to D. kuriphilus by using the 3,3′-diaminobenzidine (DAB) staining method. Buds were examined under a stereomicroscope during key stages of pest development, including oviposition, transition from egg to larva, gall induction, and gall development. Baseline levels of H₂O₂ were detected in all buds; however, these levels varied among cultivars, with resistant cultivars exhibiting lower basal levels. The degree of H₂O₂ accumulation was found to vary depending on plant–insect interaction, physiological processes, and cultivar-specific traits. Histochemical staining revealed that brown spots indicative of H₂O₂ accumulation were concentrated in the vascular bundles of leaf primordia and in the apical regions. In resistant hybrid cultivars, the defense response was activated at an earlier stage, while in resistant Castanea sativa Mill. cultivars, the response was delayed but more robust. Although consistently high levels of H₂O₂ were observed throughout the pest interaction in susceptible cultivars, gall development was not inhibited. During the onset of physiological bud break, increased H₂O₂ accumulation was observed across all cultivars. This increase was associated with endodormancy in susceptible cultivars and with both defense mechanisms and endodormancy processes in resistant cultivars. These findings highlight the significant role of H₂O₂ in plant defense responses, while also supporting its function as a multifunctional signaling molecule involved in gall development and the regulation of physiological processes. Full article

Caragana korshinskii Kom. (CKB), widely cultivated in Inner Mongolia, China, has potential for silage feed development due to its favorable nutritional characteristics, including a crude protein content of 14.2% and a neutral detergent fiber content below 55%. However, its vascular bundle fiber structure limits the efficiency of lactic acid conversion and negatively impacts silage quality, which can be improved through mechanical crushing. Currently, conventional crushing equipment generally suffers from uneven particle size distribution, high energy consumption, and low processing efficiency. In this study, a layered aggregate model was constructed using the discrete element method (DEM), and the Hertz–Mindlin with Bonding contact model was employed to characterize the heterogeneous mechanical properties between the epidermis and the core. Model accuracy was enhanced through reverse engineering and a multi-particle-size filling strategy. Key parameters were optimized via a Box–Behnken experimental design, with a core normal stiffness of 7.37 × 10¹¹ N·m⁻¹, a core shear stiffness of 9.46 × 10¹⁰ N·m⁻¹, a core shear stress of 2.52 × 10⁸ Pa, and a skin normal stiffness of 4.01 × 10⁹ N·m⁻¹. The simulated values for bending, tensile, and compressive failure forces had relative errors of less than 10% compared to experimental results. The results showed that rectangular hammers, due to their larger contact area and more uniform stress distribution, reduced the number of residual bonded contacts by 28.9% and 26.5% compared to stepped and blade-type hammers, respectively. Optimized rotational speed improved dynamic crushing efficiency by 41.3%. The material exhibited spatial heterogeneity, with the mass proportion in the tooth plate impact area reaching 43.91%, which was 23.01% higher than that in the primary hammer crushing area. The relative error between the simulation and bench test results for the crushing rate was 6.18%, and the spatial distribution consistency reached 93.6%, verifying the reliability of the DEM parameter calibration method. This study provides a theoretical basis for the structural optimization of crushing equipment, suppression of circulation layer effects, and the realization of low-energy, high-efficiency processing. Full article

Plant hormones are critical regulators of graft union healing, yet the specific role of exogenous naphthylacetic acid (NAA) in graft union healing efficiency and grafted seedling growth remains unexplored. In this study, we investigated the effects of exogenous NAA treatment (40 mg·L⁻¹) on graft union healing and grafted seedling quality in oriental melon scion grafted onto squash rootstock. Our results demonstrated that exogenous NAA application significantly accelerated vascular bundle reconnection, a key indicator of successful graft union formation. The exogenous NAA treatment enhanced indole-3-acetic acid (IAA) biosynthesis by upregulating key enzymes (TDC, PDC, FMO, NIT, and TAA) and gene expression (CmYUCCA10, CmCYP450, CmoCYP450, and CmoTAA1). The exogenous NAA treatment also upregulated critical graft healing-related genes (CmoWIND1, CmoWOX4, CmoCDKB1;2, CmTMO6, CmoTMO6, CmVND7, and CmoVND7). The exogenous NAA-treated seedlings exhibited better growth. These findings reveal the potential molecular and physiological mechanisms by which exogenous NAA promotes graft union healing of melon grafted onto squash. While the results highlight the potential of exogenous NAA as a grafting enhancer under controlled conditions, further field studies are also needed to validate its practical applicability in commercial production. Full article

Apple (Malus domestica Borkh.) is an economically important fruit. The use of nitrate by plants plays a crucial role in their growth and development, and its absorption and dispersal are controlled by nitrate transport proteins (NRTs). In this study, we investigated the potential function of MdNRT2.4 under low-nitrogen (N) stress by overexpressing it in tobacco. Compared with plants treated with a normal nitrogen level (5 mM), the MdNRT2.4 overexpression lines under low-N stress (0.25 mM) exhibited significantly greater plant height and width, as well as larger leaves and a higher leaf density, than wild-type plants, suggesting that the overexpression of MdNRT2.4 enhances the low-N tolerance of tobacco. Enhanced antioxidant enzyme activities in the MdNRT2.4 overexpression plant lines promoted the scavenging of reactive oxygen species, which reduced damage to their cell membranes. GUS staining of pMdNRT2.4::GUS-transformed Arabidopsis thaliana lines showed that MdNRT2.4 was expressed in the roots, vascular bundles, seeds in fruit pods, and young anther sites, suggesting that MdNRT2.4 mediates the transport of nitrate to these tissues, indicating that MdNRT2.4 might promote nitrate utilization in apple and improve its tolerance to low-N stress. Experiments using yeast one-hybrid and dual-luciferase assays revealed that MdbHLH3 binds to the MdNRT2.4 promoter and activates its expression. MdbHLH3 belongs to the basic helix–loop–helix (bHLH) transcription factor (TF). It is speculated that MdbHLH3 may interact with the promoter of MdNRT2.4 to regulate N metabolism in plants and enhance their low-N tolerance. This study establishes a theoretical framework for investigating the regulatory mechanisms of low-N responsive molecules in apple, while simultaneously providing valuable genetic resources for molecular breeding programs targeting low-N tolerance. Full article

Grafting is widely used as a breeding method to enhance productivity and resilience. However, the mechanisms of graft healing remain poorly understood. In this study, we performed Malus domestica (‘Hanfu’) homograft and observed morphological and anatomical changes during the healing process in the graft junction within 40 days after grafting (DAG). The results showed that the healing process was divided into two phases: 0–20 days (callus proliferation phase) and 20–40 days (vascular bundle reconnection phase). During the early stage (20 DAG), gene expression exhibited asymmetry between the scion and rootstock, whereas synchronization occurred in the late stage (40 DAG). Transcriptomic and metabolomic analyses of the scion and rootstock during these two critical phases identified that differentially expressed genes (DEGs) were enriched in “Carbon fixation by Calvin cycle” and “photosynthesis-related pathways”, while differentially expressed metabolites (DEMs) were clustered in “Galactose metabolism”, implying a critical role of carbohydrates in grafting. Genes encoding enzymes involved in sugar biosynthesis, such as amylase (MdAMY), invertase (MdINV), galactinol synthase (MdGS), raffinose synthase (MdRS), and stachyose synthase (MdSS), were generally more highly expressed during Phase I than Phase II. In contrast, genes encoding enzymes related to sugar consumption, such as fructose kinases (MdSUS), cellulose synthases (MdCESA), and galacturonosyltransferase (MdGAUT), showed weak expression in Phase I but were strongly activated in Phase II. Glucose, sucrose, galactose, and melibiose levels increased significantly at 20 DAG compared with 0 DAG and subsequently decreased by 40 DAG. Exogenous application of 0.5% sucrose, raffinose, or melibiose significantly enhanced vascular bundle reconnection rates at 7 DAG compared with the control group (p < 0.01), confirming the pivotal role of sugar metabolism in graft healing. Full article

Yam (Dioscorea opposita) tuber development is a complex process regulated by various phytohormones, with gibberellin (GA) playing a crucial role. However, the underlying mechanisms and interaction of GA with other phytohormone pathways on yam tuber development remain incompletely understood. This study investigated the regulatory role of GA and its crosstalk with other phytohormones during yam tuber growth through phenotypic, cytological, physiological, and transcriptomic as well as targeted phytohormone metabolomics analyses. The results reveal that exogenous GA promoted tuber enlargement increases vascular bundle and the number and diameter of sieve tubes, and alters the expression of GA anabolism genes and GA signal transduction pathways. Integrated transcriptome and targeted metabolomics analyses revealed coordinated changes in GA and ethylene (ETH) biosynthesis and signaling pathways during tuber development, particularly DELLA-GAI2 acting as a negative regulator of GA signaling. Overexpression of DoDELLA-GAI2 in transgenic tobacco significantly reduced GA level, starch, cytokinin (CTK), and ETH content, as well as aerenchyma tissue growth and parenchyma cell size. Exogenous GA and ethephon treatments increased GA, starch, CTK, and ETH content, and downregulated DoDELLA-GAI2 gene expression. The yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays confirmed a direct interaction between DoDELLA-GAI2 and DoMTCPB, an upstream gene-encoding key enzyme in ETH biosynthesis. DoDELLA-GAI2 acts as a negative regulator of ETH synthesis by interacting with DoMTCPB. GA-induced degradation of DoDELLA-GAI2 relieves this inhibition, promoting ETH production and contributing to tuber growth. Taken together, our findings reveal a novel mechanism based on DoDELLA-GAI2 integrating the GA and ETH signaling processes to regulate tuber development in D. opposita, offering a potential target for improving yam crop productivity. Full article

Marfan syndrome is caused by a mutation in the FBN1 gene encoding fibrillin-1. This extracellular matrix glycoprotein, which assembles into microfibrils, is best known for its scaffolding role in the production of elastic fibers responsible for connective tissue elasticity and tensile strength. Research into Marfan syndrome mainly focuses on the pathophysiology involved in the degeneration of elastin-rich elastic fibers, which are essential components of the aortic wall. However, fibrillin-1 also exists in elastin-poor (elaunin) or elastin-free (oxytalan) microfibril bundles that were first described in the periodontal ligament (PDL). This dynamic, densely cellular, and highly vascularized tissue anchors teeth in their bone sockets and acts as a protective shock absorber during chewing. Current knowledge suggests that fibrillin microfibrils mechanically support blood vessels in the PDL and ensure their proper functioning. However, many more insights on the roles of fibrillin, especially independently of elastin, can be extracted from this tissue. Here, we review the phenotypic and functional characteristics of the PDL in connection with fibrillin-1, focusing on those related to microvessels. This review aims to shed light on this often-overlooked fibrillin-rich resource as a model for future studies investigating fibrillin functions in health and Marfan disease. Full article

Lilium holds significant horticultural and ecological importance. Understanding the morpho-anatomical diversity of the stems can provide insights into taxonomy and breeding strategies. This study comprehensively examined the stem morpho-anatomy of 71 Lilium taxa to elucidate taxonomic and structural differences. For the first time, four distinct jigsaw-puzzle-shaped shapes of epidermal cells (Ep) in monocot stems, novel I-shaped and Co-xylem (O-, X-, W-, Q-shaped) vascular bundles (Vb) in Lilium stems, and quantitative characteristics (Vb density, xylem/phloem area ratio, etc.) were systematically discovered and analyzed. Asiatic (A) and Longiflorum × A (LA) hybrids displayed epidermal appendages, while Oritenal × Trumpet (OT) hybrids featured thicker sclerenchymatous rings (Sr). Collateral Vb in hybrids visually displayed bicollateral with degraded bundle sheaths (Bs), contrasting with intact circular Bs in wild species. Ward.D clustering categorized Lilium taxa into group A (Oritenal and OT hybrids) and B (A, LA, Trumpet, Longiflorum × Oriental hybrids and wild species), with Mantel’s test identified height, Ep shape, Ep length/width ratio, cortex/Sr thickness ratio and Bs integrity as key discriminators. Bending stems exhibited a higher Vb area. These findings establish a comprehensive pheno-anatomical framework for Lilium, which can guide future breeding programs and ecological studies. Full article

Spasticity often occurs following neurological disorders such as traumatic brain injury, cerebral palsy, and stroke. Botulinum toxin (BTX) injections, especially when paired with rehabilitation, are among the most effective interventions for these patients. Various techniques for administering BTX injections to the upper limb muscles have been described. However, a standardized method for ultrasound-guided injections in the intrinsic muscles of the hand remains quite scant in the literature. The authors suggest a novel dorsal approach to treat the most common abnormal postural patterns in hand spasticity, thumb-in-palm, and intrinsic plus. This approach facilitates access to the muscles while minimizing patient discomfort, as it avoids the need to open forcibly the spastic hand. The adductor pollicis, flexor pollicis brevis, lumbrical, and interosseus muscles have been identified as primary anatomical targets to improve hand posture and function. Standardized sonographic scans are leveled with anatomical illustrations and probe/patient positioning images for interventional procedures. Additionally, tips and techniques for promptly identifying vascular bundles are included to enhance the safety of the procedures. This technical report aims to provide an easy and ready-to-use tool in clinical practice for injecting intrinsic hand muscles in spastic patients, utilizing a novel dorsal approach. Full article

Lattice materials demonstrate exceptional advantages in lightweight design applications due to their low mass density, high specific strength, and customizable topology. Inspired by the hollow vascular bundle structure of bamboo, this study develops four bio-inspired lattice configurations through two key modifications to conventional body-centered cubic (BCC) structures: Z-axis (loading direction) strut reinforcement and strut hollowing. The specimens were fabricated using AlSi10Mg powder via selective laser melting (SLM) technology, followed by the systematic evaluation of the compressive properties and the energy absorption characteristics. The experimental results reveal that the synergistic combination of Z-strut reinforcement and hollow design significantly enhances both the compressive resistance and the energy absorption capacity. The optimized BCC-5ZH configuration (5 Z-struts with full hollowing) achieves remarkable performance metrics at 0.5 g/cm³ density: yield strength (16.78 MPa), compressive strength (27.91 MPa), and volumetric energy absorption (10.4 MJ/m³). These values represent 236.9%, 283.4%, and 239.3% enhancements, respectively, compared to the reference BCC lattices with an equivalent density. Z-strut integration induces homogeneous stiffness distribution throughout the lattice architecture, while strut hollowing increases the effective moment of inertia. This structural evolution induces a failure mode transition from single shear band deformation to dual X-shaped shear band propagation, resulting in enhanced deformation sequence regulation within the lattice system. Full article

Hyperhydricity is a significant challenge in the tissue culture of blueberry plantlets, affecting their propagation, survival and quality, which results in economic losses for industrial blueberry micropropagation. The in vitro liquid propagation of two half-highbush blueberry hybrids, HB₁ and HB₂, showed that a Growtek stationary bioreactor culture system containing a liquid medium exhibited a higher hyperhydricity percentage than a Sigma glass culture system with a semi-solid medium. The percentage of hyperhydricity (75.21 ± 1.89%) and water content (72%) of HB₂ was more than that of HB₁. A scanning electron microscopy study revealed that hyperhydric plantlets from both genotypes developed slowly, had closed stomata, and displayed enlarged intercellular spaces between the palisade and spongy parenchyma layers. Disrupted vascular bundles, underdeveloped sieve elements and a weak connection between phloem and xylem tissue were also observed in hyperhydric plantlets. An analysis of mesophyll and stem tissues highlighted a compressed adaxial epidermis, which led to compact palisade parenchyma, with irregularly shaped mesophyll cells. Hyperhydric plants showed strong nuclear magnetic resonance (NMR) signals in the aliphatic, aromatic, and sugar regions, specifically at peaks of 2.0, 2.5, 4.0, 4.5, 6.0, and 6.7 ppm. These signals were attributed to the presence of catechin (C₁₅H₁₄O₆), a flavonoid compound, suggesting its significant role or accumulation in these plants under hyperhydric conditions. Despite the negative effects of hyperhydricity on commercial propagation, hyperhydric plants were found to contain higher levels of valuable untargeted metabolites, such as β-P-arbutin, chlorogenic acid, quercetin-3-O-glucoside, epicatechin, 2-O-caffeoyl arbutin, various fatty acids, β-glucose, linolenic acid, and acetyl than both in vitro and ex vitro conditions. The enrichment of bioactive compounds in blueberry enhances its antioxidant properties, nutritional profile, and potential health benefits, making them significant for plant defense mechanisms and stress adaptation. Full article

Fusarium wilt in bitter gourd caused by Fusarium oxysporum f. sp. momordicae (Fomo) is a severe plant disease that affects the world’s bitter gourd (Momordica charantia L.) cultivation. This study evaluated nine luffa hybrids for their performance as rootstocks with bitter gourd to control Fusarium oxysporum f. sp. luffae (Folu) isolate Fomh16 and Fomo isolate Fomo33. In the first evaluation, five hybrids (LF1, LF2, LF3, LF15, and LF16) exhibited resistance to the Fomh16 isolate and showed no symptoms. One hybrid, LF10, was resistant with a mean disease rating (MDR) of 0.9 at 28 days post-inoculation (dpi). Seven luff hybrids that displayed resistant and moderate resistance in the first evaluation were used as rootstocks with susceptible bitter gourd cultivars. Five rootstocks exhibited high resistance to Fomh16 and Fomo33 isolates, with their MDR ranging from 0.0 to 0.7. In addition, the findings revealed that both isolates could colonize the vascular bundle of all resistant luffa rootstocks at 28 dpi. However, the Fomo33 isolate could extend and colonize the vascular bundle of bitter gourd scion when grafted only with rootstock LF5 and LF11. The quantitative PCR results indicated that there were significant differences in the amount of the Fomo33 DNA between the bitter gourd grafted onto LF15 and LF16 rootstocks and the self-grafted plants; however, the pathogen cannot be detected in the bitter gourd scions grafted with resistant rootstocks. These findings provide valuable resistant sources that can be used as rootstocks to manage Fusarium wilt disease in bitter gourd. Full article

Miscanthus (Miscanthus Andersson) is a perennial grass for which biomaterials market has taken growing interest. Our objective was to evaluate the effect of stem internode position in Miscanthus × giganteus and Miscanthus sinensis and the impact of its anatomy and biochemical composition on internode-based composites’ mechanical properties. Stems’ bottom and top internodes were sampled for two genotypes of each species in two different years and separately added to a polypropylene matrix, and the mechanical properties of the internode-reinforced composites were measured. Before composite production, the internodes were extensively phenotyped for biochemical composition and anatomy. Stems’ bottom and top internode-based composites yielded different modulus (3203 and 2988 MPa, respectively), while tensile strength was similar (36.4 and 36.5 MPa, respectively). Significant genotype × internode interactions occurred for most variables, mainly due to differences among species, since both Miscanthus sinensis clones proved to be more stable than both Miscanthus × giganteus clones for modulus (4% and 10.2%, respectively). Regarding tensile strength, the species showed small but opposite differences between internodes. Tensile strength and modulus were rather close only in the top internodes, where good mechanical properties were associated with the lowest values of vascular bundles number and section area and highest parenchyma tissue, while opposite results were obtained in the bottom ones, only for tensile strength. Miscanthus sinensis species proved to be interesting for the stability improvement of composite mechanical properties. It appears essential for experimental purposes to stratify the sampling by internode in order to be representative of the whole stem. Full article