Stem Structure Research Articles

Effect of Growth Regulators and Nano Materials to Cope with Salinity on Anatomical Characteristics of Pea Plant

Abiotic stresses, particularly salinity, severely hinder crop productivity by disrupting physiological processes and reducing yields. Pea (Pisum sativum L.), a vital crop, is highly sensitive to salinity, making it crucial to explore strategies that enhance its tolerance to such stresses. This study investigates the effects of Ascorbic Acid (AsA), 5-Aminolevulinic Acid (ALA), and Nano-Selenium (N-Se) on the anatomical characteristics of pea plants subjected to severe salinity stress (120 mM NaCl). Transverse sections of the fourth internode and leaf blade were analyzed, focusing on stem and leaf structure. The results showed that foliar application of AsA (100 ppm) significantly improved anatomical traits, such as stem diameter, cortex thickness, and vascular bundle dimensions, compared to the control and other treatments. ALA (50 ppm) also improved anatomical features, albeit to a lesser extent, while N-Se (20 ppm) exhibited the lowest enhancement. Leaf tissue analysis revealed that AsA improved leaflet structure, increasing epidermis thickness and vascular bundle dimensions under salinity stress. The application of AsA, ALA, and N-Se mitigated the negative effects of salinity, likely due to their roles in enhancing stress tolerance, reducing oxidative damage, and improving nutrient uptake. This study highlights the potential of these bio-stimulants to improve the anatomical resilience of pea plants under salinity stress, contributing to better crop performance in saline environments.

Endophytic bacterial and fungal dynamics of community structures in lettuce stem and soil during invasion by the fungal pathogen Sclerotinia sclerotiorum

Endophytic bacterial and fungal dynamics of community structures in lettuce stem and soil during invasion by the fungal pathogen Sclerotinia sclerotiorum

Bioelectric brain activity in workers with hand-arm vibration in dynamics

Introduction. A few neurophysiologic studies have shown that changes of the bioelectrical brain activity are observed in hand-arm vibration syndrome (HAVS) patients. There is practically no information about the state of bioelectrical brain activity in the hand-arm vibration. The purpose is to study the dynamics of the formation of neurophysiologic changes in workers exposed to hand-arm vibration. Materials and methods. Electroencephalography (EEG) and registration of evoked potentials (EP) was carried out in workers exposed to hand-arm vibration (practically healthy workers, HAVS individuals who continue to work in their occupation), twice in a connected sample. The results are presented as median, upper and lower quartiles, and extensive indicators. The significance of differences was assessed using Pearson’s χ2 test, Fisher’s angular transformation, and Wilcoxon T-test. Results. In dynamics, there is a change in the EEG pattern from disorganized with a predominance of alpha activity to disorganized with a predominance of delta, and theta activity; a decrease in the spectral power of the main EEG rhythms in all main functional leads in both examined groups. Diffuse changes in the EEG indicate a multisystem nature of bioelectrical brain activity disorders with involvement of the cerebral cortex, stem, and diencephalic structures of the brain. Changes in the amplitude-temporal parameters of EP manifested by an excess of the latency of the main peaks and a decrease in amplitude, indicate an imbalance in the central nervous system, general modulating influences on the cerebral cortex of the thalamocortical systems of the brain. Limitations. One occupational group with different levels of health status – practically healthy workers, HAVS individuals who continue to work in their occupation – was enrolled in the study. Conclusion. The one-direction and progressive development of changes in the bioelectrical brain activity has been established, manifested by a restructuring of the electrical activity of the brain, desynchronization of neuronal activity, an increase in the level of functional activity of the brain, and an imbalance of general modulating influences on the cerebral cortex. The identified changes are a manifestation of the nonspecific part of the pathogenesis of HAVS.

Training Climbing Roses by Constrained Graph Search

ABSTRACTCultivated climbing roses are skillfully shaped by arranging their stems manually against support walls to enhance their aesthetic appeal. This study introduces a procedural technique designed to replicate the branching pattern of climbing roses, simulating the manual training process. The central idea of the proposed approach is the conceptualization of tree modeling as a constrained path‐finding problem. The primary goal is to optimize the stem structure to achieve the most impressive floral display. The proposed method operates iteratively, generating multiple stems while applying the objective function in each iteration for maximizing coverage on the support wall. Our approach offers a diverse range of tree forms employing only a few parameters, which eliminates the requirement for specialized knowledge in cultivation or plant ecology.

Optimization Design and SLM Manufacturing of Porous Titanium Alloy Femoral Stem.

In order to solve the loosening problem caused by stress shielding of femoral stem prostheses in clinical practice, an optimization design method of a personalized porous titanium alloy femoral stem is proposed. According to the stress characteristics of the femur, the porous unit cell structures (TO-C, TO-T, TO-B) under three different loads of compression, torsion, and bending were designed by topology optimization. The mechanical properties and permeability of different structures were studied. Combined with the porous structure optimization, a personalized radial gradient porous titanium alloy femoral stem was designed and manufactured by selective laser melting (SLM) technology. The results show that the TO-B structure has the best comprehensive performance among the three topologically optimized porous types, which is suitable for the porous filling structure of the femoral stem, and the SLM-formed porous femoral stem has good quality. The feasibility of the personalized design and manufacture of porous titanium alloy implants is verified, which can provide a theoretical basis for the optimal design of implants in different parts.

On Seedling Morphoanatomy of Asteraceae Campestral Species: Some Adaptative and Taxonomic Considerations

Theoretical Framework: The vegetation of Parana State fields is composed mainly of woody grassy savanna, and one of the largest families in specific richness is Asteraceae. The campestral Asteraceae occurs in three microhabitats as dry fields (steppes “stricto sensu”), rocky outcrops (rupestrian vegetation refuges) and humid fields (higrophyllous steppes). Morphology and structure of Asteraceae seedlings can be useful for species recognition in the field at the juvenile stage, and to understand how seedlings establish themselves in different microhabitats. Objective: The aim of this paper was to analyze the seedling structure of 17 Asteraceae species, and to summarize some considerations on anatomical characters of the seedlings, which may be variations environmentally induced and they have some taxonomic or evolutionary value. Method: Cipselae of 17 species of Asteraceae were collected in the state parks of Paraná, Brazil, and placed to germinate in Petri plates. The seedling development occurred in greenhouse. Root, hypocotyl, cotyledons, epicotyl and eophylls were sectioned in rotation microtome, and analyzed in light microscope. Cotyledons and eophylls were investigated in a scanning electronic microscope. Results: Roots are diarch or tetrarch. Hypocotyl may have the root structure and partially or wholly as transition root-stem structure. Epicotyl shows the stem structure. Cotyledons and eophylls are dorsiventral. Trichome density and amphistomaty are xeromorphic characters that occur in the cotyledons and eophylls of the species. Conclusion: Some structural characters have diagnostic value for separation of investigated species, such as hypocotyl structure, root/stem transition type, epidermis, mesophyll tissues and midrib saliency of the cotyledons and eophylls, and presence of secretory ducts.

Langevin Dynamics Study on the Driven Translocation of Polymer Chains with a Hairpin Structure.

The hairpin structure is a common and fundamental secondary structure in macromolecules. In this work, the process of the translocation of a model polymer chain with a hairpin structure is studied using Langevin dynamics simulations. The simulation results show that the dynamics of hairpin polymer translocation through a nanopore are influenced by the hairpin structure. Hairpin polymers can be classified into three categories, namely, linear-like, unsteady hairpin, and steady hairpin, according to the interaction with the stem structure. The translocation behavior of linear-like polymers is similar to that of a linear polymer chain. The time taken for the translocation of unsteady hairpin polymers is longer than that for a linear chain because it takes a long time to unfold the hairpin structure, and this time increases with stem interaction and decreases with the driving force. The translocation of steady hairpin polymers is distinct, especially under a weak driving force; the difficulty of unfolding the hairpin structure leads to a low translocation probability and a short translocation time. The translocation behavior of hairpin polymers can be explained by the theory of the free-energy landscape.

Localized stem structures in quasi-resonant two-soliton solutions for the asymmetric Nizhnik–Novikov–Veselov system

Elastic collisions of solitons generally have a finite phase shift. When the phase shift has a finitely large value, the two vertices of the (2 + 1)-dimensional two-soliton are significantly separated due to the phase shift, accompanied by the formation of a local structure connecting the two V-shaped solitons. We define this local structure as the stem structure. This study systematically investigates the localized stem structures between two solitons in the (2 + 1)-dimensional asymmetric Nizhnik–Novikov–Veselov system. These stem structures, arising from quasi-resonant collisions between the solitons, exhibit distinct features of spatial locality and temporal invariance. We explore two scenarios: one characterized by weakly quasi-resonant collisions (i.e. a12 ≈ 0), and the other by strongly quasi-resonant collisions (i.e. a12 ≈ +∞). Through mathematical analysis, we extract comprehensive insights into the trajectories, amplitudes, and velocities of the soliton arms. Furthermore, we discuss the characteristics of the stem structures, including their length and extreme points. Our findings shed new light on the interaction between solitons in the (2 + 1)-dimensional asymmetric Nizhnik–Novikov–Veselov system.

Stiffness and stability of bamboo stem- A optimal design perspective

During the evolution process, a bamboo stem achieves a significant height (up to 20 m) to fulfil its phototropic requirements. While on land, the stem is mostly subjected to bending load which makes it liable to fail by uprooting. However, this failure is prohibited by smart structure of bamboo stem which includes graded arrangement of fibre bundles in the cross-section and a tapered cantilever form of the stem. This paper attempts to understand the optimal design of bamboo stem through the relationship between the stellar arrangement of stiff fibre bundles in the cross-section and the tapered form. In this work, a comparison between two types of stellar arrangement, namely uniform and graded, is presented in view of non-linear bending analysis through elastica theory and fracture-induced delamination, both numerically. It is observed from the results that a bamboo stem prefers to evolve with graded stellar arrangement which provides gradation of stiffness and toughness over the cross-section; the trend in toughness being opposite to that of stiffness. Moreover, interplay of stellar arrangement and gradation of stiffness-toughness thereof is found to be the governing mechanism for ensuring its mechanical integrity and stability in view of an optimal design perspective. The smart structure of bamboo is recommended for bio-mimicking.

Advancing cellular insights: Super-resolution STORM imaging of cytoskeletal structures in human stem and cancer cells

Fluorescence microscopy is an important tool for cell biology and cancer research. Present-day approach of implementing advanced optical microscopy methods combined with immunofluorescence labelling of specific proteins in cells is now able to deliver optical super-resolution up to ∼25 nm. Here we perform super-resolved imaging using standard immunostaining protocol combined with easy stochastic optical reconstruction microscopy (easySTORM) to observe structural differences of two cytoskeleton elements, actin and tubulin in three different cell types namely human bone marrow-derived mesenchymal stem cells (MSCs), human glioblastoma (U87MG) and breast cancer (MDAMB-231) cells. The average width of the actin bundle obtained from STORM images of stem cells is observed to be larger than the same for U87MG and MDAMB-231 cells. No significant difference is however noticed in the width of the tubulin within the same cells. We also study the functional effect on the 2D migration potential of MDAMB-231 cells silenced for NICD1 and β-catenin. Although similar migration speed is observed for cells with the above two conditions compared to their control cells, easySTORM images show that widths of the actin in MDAMB-231 cells in β-catenin silenced is significantly lower than the same in control cells. Such minute differences however are not observable in widefield images. The outcome of our easySTORM investigation should benefit the researchers carrying out detailed investigations of the cellular structure and potential therapeutic applications.

The effect of an anatomical structure of a stem on pea lodging

Currently, in our country there is growing interest in the cultivation of high-tech pea varieties, which are characterized by uniform maturity, high productivity, and lodging resistance. Thus, breeding for lodging resistance is one of the most important criteria in pea breeding programs. The purpose of the current study was to search for anatomical indicators that could serve as a criterion when selecting pea samples for lodging resistance. The field trials were carried out in the fields of the laboratory for legumes breeding and seed production, the laboratory study was conducted in the laboratory for cell breeding of the FSBSI “ARC “Donskoy” in 2022–2023. The estimation of lodging resistance was carried out on 22 pea samples of the regional and foreign breeding. The studied samples differed in plant height, morpho-anatomical features of a stem structure, and lodging resistance. Based on the results of estimating an anatomical structure of a pea stem, there were identified such samples with a complex of traits (number of bundles, ratio of a number of bundles to stem tissues) as ‘Lu-153-06’, ‘G-1234’, ‘G-1193’, ‘G-1288’, ‘AKM’, ‘G-1313’, ‘Flagman 10’, ‘G-1313’. The analysis of correlations between anatomical indicators and field resistance to lodging has shown a high positive correlation with a stem height (r = 0.78±0.14), a mean negative correlation with a plant height (r = -0.66±0.17), and a mean positive correlation with a number of vascular bundles (r = 0.69±0.16). The experimental results allow concluding that the estimation of lodging resistance based on an anatomical structure of a pea stem is effective and can serve as a tester for lodging resistance.

Postoperative hemorrhages in vestibular schwannoma surgery pontine hemorrhage. Clinical case report

Vestibular schwannoma (acoustic neuroma) is a benign tumor that develops from Schwann cells and can be life-threatening. Nowadays, surgical treatment is the method of choice in the management of patients with this type of tumor. We present a clinical case report of 71 y.o. patient with vestibular schwannoma (Koos grade IV, Samii grade 4B) with severe compression of the pons and the left cerebellar hemisphere. Microsurgical removal of the tumor was performed via the retrosigmoid approach. Starting from postoperative day 1, signs of respiratory distress developed. Control multislice spiral computed tomography (MSCT) of the brain revealed the area of hemorrhage in the left regions of the pons. On postoperative day 24 the patient's condition rapidly worsened progressing to coma with pronounced arterial hypotonia and cardiac arrest. Hemorrhage in the brain stem structures is a rare and life-threatening postoperative complication in vestibular schwannoma surgery. The incidence of postoperative hemorrhage is 2–11% of cases. Vascular complications are the leading cause of mortality. The key predisposing factors are older age, large and giant size of the tumor, tumor invasion into the pia mater of the brainstem, and vascularization of the tumor stroma. Comprehensive assessment of the tumor blood supply status, the state of the brainstem, intra- and postoperative clinical and neurophysiological monitoring, careful and thorough dissection of the tumor capsule and strict control of blood pressure in the postoperative period are the basis for the prevention of these complications.

Crashworthiness analysis of bumper structures with bionic hexagonal energy-absorbing boxes inspired by the characteristic of horsetails

Inspired by the cross-sectional structure and transverse diaphragm of horsetail stem, six types of bionic bumper structures are designed and their crashworthiness performances are investigated by numerical simulation and compared with conventional bumper structure. Results show that all types of the bionic bumper structure present excellent crashworthiness performances. Their specific energy absorption (SEA) increases more than 80% compared to original bumper structure, indicating the effectiveness of bionic design. The maximum increment in SEA under the frontal collision, the 30° inclined collision and the 40% offset collision reaches 135.32%, 96.55%, and 118.85%, respectively.

Target-responsive triplex aptamer nanoswitch enables label-free and ultrasensitive detection of antibody in human serum via lighting-up RNA aptamer transcriptions

Accurate and sensitive monitoring of the concentration change of anti-digoxigenin (Anti-Dig) antibody is of great importance for diagnosing infectious and immunological diseases. Combining a novel triplex aptamer nanoswitch and the high signal-to-noise ratio of lighting-up RNA aptamer signal amplification, a label-free and ultrasensitive fluorescent sensing approach for detecting Anti-Dig antibodies is described. The target Anti-Dig antibodies recognize and bind with the nanoswitch to open its triplex helix stem structure to release Taq DNA polymerase and short ssDNA primer simultaneously, which activates the Taq DNA polymerase to initiate downstream strand extension of ssDNA primer to yield specific dsDNA containing RNA promoter sequence. T7 RNA polymerase recognizes and binds to these promoter sequences to initiate RNA transcription reaction to produce many RNA aptamer sequences. These aptamers can recognize and bind with Malachite Green (MG) dye specifically and produce highly amplified fluorescent signal for monitoring Anti-Dig antibodies from 50 pM to 50 nM with a detection limit down to 33 pM. The method also exhibits high selectivity for Anti-Dig antibodies and can be used to discriminate trace Anti-Dig antibodies in diluted serum samples. Our method is superior to many immunization-based Anti-Dig antibody detection methods and thus holds great potential for monitoring disease progression and efficacy.

Palaeoenvironmental reconstruction of Holocene calcareous tufas distributed over a manganese deposit in Mexico

The Holocene calcareous tufa deposits are located in the north-central sector of the state of Hidalgo, Mexico. These deposits outcrop on the Upper Jurassic Chipoco Formation in the Molango Manganese District. Calcareous tufa deposits correspond to carbonate formations of inactive tufas disconnected from the current hydrological network. To better understand the textural, geochemical, and biological characteristics and environmental conditions during their formation, a detailed study involving field analysis, X-ray diffraction analysis, X-ray fluorescence analysis, and morphometric analysis with light microscopy, and scanning electron microscopy was carried out. Similarly, 14C analysis was undertaken to determine the age of the deposit. On this basis, two biofacies were defined, one with stem structures and the other with Phyto clasts, bryophytes (Plagiomnium cuspidatum), and copepods, limited both at the base and the top by lenticular-shaped erosive surfaces and sigmoidal clinoforms. These bio facies formed in lacustrine and paludal environments, and barrier waterfalls. From a geomorphological point of view, the accumulations of these calcareous tufas originated on slopes and/or at the foot of karstic springs, where the accumulation of material originated from the height of the spring with respect to the bottom of the valley, giving rise to a set of stepped tuffaceous plains with a wedge-shaped profile, colonized by important masses of bryophyte mounds, copepods, and vascular plants. This suggests a swampy environment where sedimentation took place in shallow water accumulations, where there is clear evidence of exposure and pedogenetic modification, indicating wet and dry episodes that translate into seasonal fluctuations in the water table. Six mineral phases were observed including silicates, carbonates and arsenates. The 14C analysis indicates that the plant found in the charcoal sample within the calcareous tufa deposit is of Holocene age.

Green synthesis of oxygen-enriched tobacco stem-derived porous carbon via pre-oxidation and self-activation for high-performance supercapacitors

The use of agricultural and forestry waste to produce functional materials is a significant approach to achieving carbon neutrality. Herein, a green and cost-effective pre-oxidation and self-activation approach has been adapted to produce porous carbon from discarded tobacco stems for supercapacitors. The analysis of tobacco stem structure evolution reveals that the pre-oxidation process facilitated the cross-linked structure of the tobacco stem and the formation of KCl crystals, endowing tobacco stem-derived porous carbon with abundant micropores and high oxygen content during self-activation. The impact of pre-oxidation and self-activation temperature on the carbon structural characteristics of tobacco stems is systematically investigated. The optimized porous carbon exhibited a specific capacitance of 320 F/g at 0.5 A/g with good rate capability. Besides, it delivered a high energy density of 10.68 Wh/kg in a symmetrical supercapacitor. This work provides a green route for preparing carbon electrode materials for high-performance supercapacitors using agricultural and forestry wastes.

Winter flax: Stem structure, fibre properties and reinforcement potential for composite materials

Climate change is characterized by rising temperatures and an increased risk of spring water deficit, both of which threaten the cultivation of textile flax. With the multiplication and intensification of these phenomena, fibre plant yields have become increasingly uncertain in recent years, leading to shorter stems as well as reduced yields. In this context, winter flax cultivation emerges as a solution to sustain the exploitation of this plant. Sown before winter, it can resist periods of spring water stress, owing to the early development of it root system, and is also protected from the summer heat. In this study, we investigate the stem architecture and fibres properties of two winter flax varieties, in comparison to spring flax. Cross-sections reveal that both winter and spring flax have a similar plant structure. The part located at mid-height of the winter stem contains the most fibres, accounting for around 23% of the biomass. At the middle of the stem, the elementary fibres of the Cirrus and Olga varieties have an average length of 20.9 ± 7.7 mm and 30.0 ± 10.8 mm, respectively. At this same plant height, winter flax fibres of the Cirrus and Olga varieties have an average Young’s modulus of 63.6 ± 18.8 GPa and 57.6 ± 20.8 GPa, and an average strength at break of 1248 ± 554 MPa and 1187 ± 627 MPa, respectively. As a conclusion, winter flax has a similar length and mechanical properties to spring flax and therefore offers the same potential for textile applications. In addition, as demonstrated in this study, winter flax can be similarly useful as a reinforcement in composite materials.

Bamboo-inspired lightweight, mechanically-stable and vibration-damping structural members for engineering applications

After millions of years of natural evolution, bamboo stems have formed exquisite variable cross-section hollow multi-node structures that are lightweight, tough, and stable. Bamboo is difficult to break and damage from the roots under dynamic loads, providing an important reference for te biomimetic design of lightweight components. This paper investigates the structural characteristics and variation patterns of bamboo stems and subsequently proposes an imitation bamboo stem structure design strategy for engineering structural members, namely, imitation bamboo double-jointed columns (IDJC). We establish a macro scale finite element model to predict the mechanical properties and failure modes of the IDJC under cyclic bending loads, and validate the model using experimental and analytical methods. The simulation and experimental results show that compared with traditional double-jointed columns (DJC), the weight of the IDJC is reduced by 41.7 %. Under bending load, the compressive stress of each section is approximately equal, reducing stress concentration, and increasing bending resistance. The strength to weight ratio of IDJC is 1.96 times that of DJC, indicating lightweight and high-strength characteristics. The stiffness degradation, energy dissipation, and damping and vibration reduction performance of the IDJC were also evaluated. The results showed that compared with the DJC, the stiffness degradation rate of the IDJC decreased by 6.87 times, the energy dissipation rate increased by 1.07 times, and the damping and vibration reduction performance improved by 48.40 %, reflecting a high stability and robust vibration reduction performance. The results demonstrate the potential application of biomimetic structures for the development and design of resource-rich, low-carbon, and sustainable bamboo for bamboo engineering members with excellent performance and functionality. Biomimetic structures have great potential in replacing nonrenewable structural materials in the fields of civil engineering and transportation.

NIGHTSHADE NECTAR: A MULTIFACETED DIVE INTO MEDICINAL, POLLEN, AND STEM ANATOMIES OF FIVE SOLANACEAE WONDERS

This comprehensive study delves into the intricate anatomy and reproductive biology of five prominent members of the Solanaceae family: Capsicum frutescens L., Solanum lycopersicum L., Solanum torvum Sw., Datura stramonium L., and Solanum melongena L. Through detailed anatomical examinations, including stem structure analyses, and investigations into pollen germination processes, this research elucidates the unique characteristics and adaptations of each species. Additionally, the study provides essential insights into the materials required for free-hand sectioning and pollen viability testing, facilitating further research in plant anatomy and reproductive physiology. With a focus on both morphological and physiological aspects, this work contributes to a deeper understanding of Solanaceae plant species and their ecological significance.

Characterisation of the Arabidopsis thaliana telomerase TERT-TR complex

Most eukaryotic organisms employ a telomerase complex for the maintenance of chromosome ends. The core of this complex is composed of telomerase reverse transcriptase (TERT) and telomerase RNA (TR) subunits. The TERT reverse transcriptase (RT) domain synthesises telomeric DNA using the TR template sequence. The other TERT domains contribute to this process in different ways. In particular, the TERT RNA-binding domain (TRBD) interacts with specific TR motif(s). Using a yeast 3-hybrid system, we show the critical role of Arabidopsis thaliana (At) TRBD and embryophyta-conserved KRxR motif in the unstructured linker preceding the TRBD domain for binding to the recently identified AtTR subunit. We also show the essential role of the predicted P4 stem and pseudoknot AtTR structures and provide evidence for the binding of AtTRBD to pseudoknot and KRxR motif stabilising interaction with the P4 stem structure. Our results thus provide the first insight into the core part of the plant telomerase complex.