Length Density Research Articles

Responses of arbuscular mycorrhizal fungal morphological traits and the diversity of spore-associated bacteria to simulated nitrogen deposition and drought in a Cunninghamia lanceolata plantation soil

Arbuscular mycorrhizal (AM) fungi play an important role in plant nutrient absorption and stress resistance. AM fungal spore-associated bacteria are essential for mycorrhizal colonization, but their responses to environmental changes remain largely unknown. We collected surface soil samples from a Chinese fir plantation in both summer and winter to investigate the responses of AM fungal morphological traits and spore-associated bacterial communities to simulated nitrogen deposition (40 kg N·hm-2·a-1 addition) and drought (-50% precipitation exclusion). Our results showed that nitrogen addition and precipitation exclusion significantly affected AM fungal spore density and extraradical hyphal length, respectively. AM fungal intraradical colonization rate, extraradical hyphal length and spore density were significantly differed between the two seasons. Compared to control (no nitrogen addition and no precipitation exclusion treatment), both nitrogen addition and precipitation exclusion significantly reduced spore density in winter, while precipitation exclusion alone and the combined nitrogen addition and precipitation exclusion significantly increased extraradical hyphal length in summer. The dominant spore-associated bacterial phyla were Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Planctomycetes. Nitrogen addition and precipitation exclusion did not affect the diversity of spore-associated bacteria. However, the combined nitrogen addition and precipitation exclusion treatment altered the composition of the bacterial community, with significant variations between the two seasons. The spore-associated bacterial diversity was significantly higher and community variability (or turnover) was lower during summer than winter. Soil total nitrogen, nitrate nitrogen and dissolved organic carbon were important factors influencing the bacterial community composition. In all, the effects of nitrogen addition and precipitation exclusion on the morphological traits of AM fungi are seasonally dependent. The combination of nitrogen addition and precipitation exclusion has a significant impact on AM fungal spore-associated bacterial community structure.

Improvement of Cognitive Functions And Neurotrophic Effects through by Α5‐GABAA Receptor Positive Allosteric Modulation in Animal Models of Risk for Alzheimer’s Disease

AbstractBackgroundReduced GABA/somatostatin (SST) signaling is reported in psychiatric, stress‐related and neurodegenerative disorders. SST+ interneurons from cortical layers and the hippocampus inhibit the dendrites of excitatory neurons, largely through α5‐containing GABAA receptors (α5‐GABAAR). Recently, we showed that an α5‐positive allosteric modulator (α5‐PAM) alleviates working memory deficits and reverses neuronal atrophy in old mice. We then started to investigate the behavioral and neurotrophic effects of this α5‐PAM in animal models of aging, chronic stress, and β‐amyloid load, as risk factor for developing Alzheimer’s disease.MethodThree studies are presented, with ∼12 mice/group, 50% female: 1) Young C57BL6 subjected to unpredictable chronic mild stress (UCMS) to induce cognitive deficits. 2) 22 month‐old C57BL6 developing an age‐related cognitive decline. 3) 5xFAD transgenic mice with progressive amyloid‐related cognitive decline. In all studies, efficacy of chronic administration of GL‐II‐73 (30mg/kg, p.o, for 4 weeks) at rescuing cognitive deficits across 3 domains was assessed. Working memory was assessed in an alternation task, spatial memory in the water maze, and cognitive flexibility in a set‐shifting assay. Brains were then stained using Golgi‐Cox technique (n = 4brain/group; 8cell/brain) for quantification of dendritic length and spine density in the prefrontal cortex and hippocampus (NeuroLucida).ResultChronic treatment in all models reversed cognitive deficits across domains (ps<0.01), with a strong effect on working memory. Chronic treatment also significantly reversed UCMS‐, age‐, or amyloid‐induced dendritic shrinkage and reduction of spine density at apical and basal dendrites (p<0.001 in PFC and CA1).ConclusionTogether, results support that selective α5 targeting of GABAA receptors overcomes chronic stress‐, aging‐, or amyloid‐related cognitive deficits and detriments in neuronal morphology. This represents the first intervention targeting the GABAergic system to have a symptomatic and disease‐modifying therapeutic potential in a transdiagnostic manner. This could represent a major avenue for clinical development for patients suffering from cognitive deficits across brain disorders.

Low-dose exposure to malathion and radiation results in the dysregulation of multiple neuronal processes, inducing neurotoxicity and neurodegeneration in mouse

Neurodegenerative disorders are a debilitating and persistent threat to the global elderly population, carrying grim outcomes. Their genesis is often multifactorial, with a history of prior exposure to xenobiotics such as pesticides, heavy metals, enviornmental pollutants, ionizing radiation etc,. A holistic molecular insight into their mechanistic induction upon single or combinatorial exposure to different toxicants is still unclear. In the present study, one-month-old C57BL/6 male mice were administered orally with malathion (50 mg/kg body wt. for 14 days) and single whole-body radiation (0.5 Gy) on the 8th day. Post-treatment, behavioural assays for exploratory behaviour, memory, and learning were performed. After sacrifice, brains were collected for histology, biochemical assays, and transcriptomic analysis. Transcriptomic analysis revealed several altered processes like synaptic transmission and plasticity, neuronal survival, proliferation, and death. Signalling pathways like MAPK, PI3K-Akt, Apelin, NF-κB, cAMP, Notch etc., and pathways related to neurodegenerative diseases were altered. Increased astrogliosis was observed in the radiation and coexposure groups, with significant neuronal cell death and a reduction in the expression of NeuN. Sholl analysis, dendritic arborization and spine density studies revealed decreased total apical neuronal path length and dendritic spine density. Reduced levels of the antioxidants GST and GSH and acetylcholinesterase enzyme activity were also detected. However, no changes were seen in exploratory behaviour or learning and memory post-treatment. Thus, explicating the molecular mechanisms behind malathion and radiation can provide novel insights into external factor-driven neurotoxicity and neurodegenerative pathogenesis.

Characterization of brain metabolism, volume, and vasculature of the 5xFAD mouse model of Alzheimer’s Disease across lifespan.

AbstractBackgroundThe MODEL‐AD Consortium seeks to develop the next generation of Alzheimer’s Disease models based on human data. A popular model of familial AD is the 5xFAD mouse, characterized by early amyloid‐β deposition and cognitive decrements. Despite numerous studies, the 5xFAD mouse has not been comprehensively phenotyped for vascular and metabolic features over its lifespan.MethodMale and female 5xFAD and WT littermates underwent in vivo 18F‐FDG‐PET imaging at 4, 6, and 12 months of age to evaluate regional glucose metabolism. A separate cohort of mice (4, 8, 12 months) underwent “vessel painting” that labels all cerebral vessels with a fluorescent dye. “Vessel painted” brains were analyzed for vascular characteristics such as vessel density, junction density, vessel length, network complexity, number of collaterals and vessel diameter.ResultsOur analyses revealed that vessel length, vessel and junction densities increased from 4 to 12 months on the cortical surface in both 5xFAD and WT mice. The number of collateral vessels between the middle cerebral artery (MCA) and the anterior and posterior cerebral arteries decreased with age but their diameters were significantly increased only in 5xFAD mice. MCA average vessel length was decreased in 5xFAD mice compared to WT. Analysis of 18F‐FDG cortical uptake found significant interactions between WT and 5xFAD mice spanning 4‐12 months of age in retrosplenial, somatosensory and visual cortices. Broadly, 5xFAD males had increased 18F‐FDG uptake at 12 months of age compared to WT mice. In most cortical regions, female 5xFAD mice had reduced FDG uptake compared to WT across the lifespan. In males these metabolic increases coincided with decreased vessel characteristics.ConclusionThe 5xFAD mouse exhibits AD‐like cognitive deficits with age that are associated with increasing amyloid‐β deposition. No significant differences were found in cortical vascular features although males and females exhibited opposite effects in 18F‐FDG uptake. The MCA supplies blood to large portions of the motor cortex and increased vessel lengths and decreased collaterals along with higher metabolic rates in 5xFAD mice may be related to increasing behavioral deficits via metabolic insufficiency or other mechanisms.

Characterization of brain metabolism, volume, and vasculature of the 5xFAD mouse model of Alzheimer’s Disease across lifespan

AbstractBackgroundThe MODEL‐AD Consortium seeks to develop the next generation of Alzheimer’s Disease models based on human data. A popular model of familial AD is the 5xFAD mouse, characterized by early amyloid‐ß deposition and cognitive decrements. Despite numerous studies, the 5xFAD mouse has not been comprehensively phenotyped for vascular and metabolic features over its lifespan.MethodMale and female 5xFAD and WT littermates underwent in vivo 18F‐FDG‐PET imaging at 4, 6, and 12 months of age to evaluate regional glucose metabolism. A separate cohort of mice (4, 8, 12 months) underwent “vessel painting” that labels all cerebral vessels with a fluorescent dye. “Vessel painted” brains were analyzed for vascular characteristics such as vessel density, junction density, vessel length, network complexity, number of collaterals and vessel diameter.ResultOur analyses revealed that vessel length, vessel and junction densities increased from 4 to 12 months on the cortical surface in both 5xFAD and WT mice. The number of collateral vessels between the middle cerebral artery (MCA) and the anterior and posterior cerebral arteries decreased with age but their diameters were significantly increased only in 5xFAD mice. MCA average vessel length was decreased in 5xFAD mice compared to WT. Analysis of 18F‐FDG cortical uptake found significant interactions between WT and 5xFAD mice spanning 4‐12 months of age in retrosplenial, somatosensory and visual cortices. Broadly, 5xFAD males had increased 18F‐FDG uptake at 12 months of age compared to WT mice. In most cortical regions, female 5xFAD mice had reduced FDG uptake compared to WT across the lifespan. In males these metabolic increases coincided with decreased vessel characteristics.ConclusionThe 5xFAD mouse exhibits AD‐like cognitive deficits with age that are associated with increasing amyloid‐ß deposition. No significant differences were found in cortical vascular features although males and females exhibited opposite effects in 18F‐FDG uptake. The MCA supplies blood to large portions of the motor cortex and increased vessel lengths and decreased collaterals along with higher metabolic rates in 5xFAD mice may be related to increasing behavioral deficits via metabolic insufficiency or other mechanisms.

Response of yield, root traits and plasticity of nitrogen-efficient cultivars of drip-irrigated rice to a nitrogen environment

The response of drip-irrigated rice physiological traits to water and fertilisers has been widely studied. However, the responses of yield, root traits and their plasticity to the nitrogen environment in different nitrogen-efficient cultivars are not fully understood. An experiment was conducted from 2020-2022 with high nitrogen efficient (high-NUE) cultivars (T-43) and low-NUE cultivars (LX-3), and four nitrogen levels (0, 150, 300, and 450 kg ha-1) under drip irrigation in large fields were used. The aim was to study the relationship between root morphology, conformation, biomass, and endogenous hormone content and yield and nitrogen use efficiency. The results showed the following: 1) Under the same N application rate, compared with LX-3, T-43’s yield, N partial factor productivity (PFP), fine root length density (FRLD), shoot dry weight (SDW), root indole-3-acetic acid (IAA), and root zeatin and zeatin riboside (Z+ZR) were significantly increased by 11.4-18.9%, 11.3-13.5%, 11.6-15.7%, 9.9-31.1%, 6.1-48.1%, and 22.8-73.6%, respectively, while the root-shoot ratio (RSR) and root abscisic acid (ABA) were significantly decreased (P<0.05). 2) Nitrogen significantly increased rice root morphological indexes and endogenous hormone contents (P<0.05). Compared to N0, yield, root length density (RLD), surface area density (SAD), Root volume density (RVD), and root endogenous hormones (IAA, Z+ZR) were significantly increased in the 2 cultivars under N2 by 61.6-71.6%, 64.2-74.0%, 69.9-105.6%, 6.67-9.91%, 54.0-67.8%, and 51.4-58.9%, respectively. Compared with N3, the PFP and N agronomic efficiency (NAE) of nitrogen fertiliser under N2 increased by 52.3-62.4% and 39.2-63.0%, respectively. 3) The response of root trait plasticity to the N environment significantly differed (P<0.05). Compared with LX-3, T-43 showed a longer root length and larger specific surface area, which is a strategy for adapting to changes in the nutrient environment. For rice cultivars with high-NUE, the root-shoot ratio was optimised by increasing the FRLD, root distribution in upper soil layers, and root endogenous hormones (IAA, Z+ZR) under suitable nitrogen conditions (N2). An efficient nutrient acquisition strategy can occur through root plasticity, leading to increased yield and NUE.

Moderate grazing weakens legacy effects of grazing history on primary productivity and biodiversity in a meadow grassland

Herbivore grazing has long-lasting effects on the structure and functions of grassland ecosystems, even after the grazing pressure has ceased. These lasting effects are known as grazing legacy effects and significantly affect plant productivity and biodiversity, with the magnitude increased with grazing intensity and further led to grassland degradation. Fencing is a common approach used for restoring degraded grasslands by excluding grazing. Moderate grazing representing a controlled level of grazing intensity is believed to be a useful way to restore ecological functions and thus mitigate grazing legacies. However, how fencing and ongoing moderate grazing affect grazing legacy effects remain unclear and rarely tested with field experiments, particularly with different grazing histories. Here, we investigated aboveground net primary productivity (ANPP), species richness, litter, soil organic carbon (SOC), soil dissolved nitrogen (DON) and hyphal length density (HLD) in 2015 (fencing for 1 year) and 2018 (fencing vs moderate grazing for the subsequent 3 years) after 0, 2, 5, 7 and 12 years of free grazing in a meadow steppe to explore how moderate grazing and fencing affect grazing legacy effects with different histories. We observed a decline in ANPP and species richness with increasing grazing histories, and the magnitude of grazing legacy effects increased accordingly. In most grazing histories, moderate grazing had a greater impact than fencing in reducing the grazing legacy effects on ANPP and species richness. However, with a grazing history of 12 years, moderate grazing led to a smaller increase in ANPP compared to fencing. Additionally, the grazing legacy effects on ANPP and species richness weakened with longer fencing duration for excluding grazing. Litter, SOC, DON and HLD exhibited consistent patterns with the dynamics of ANPP and species richness. Our results indicate that grazing legacy effects on ANPP and species richness intensify with prolonged grazing histories, suggesting that grazing history have stronger impacts on grassland ecosystem functions and structure. The study implies that moderate grazing is an effective strategy for restoring degraded grasslands, particularly for species richness and with short-term grazing histories, instead of relying solely on fencing. The changes of soil variables underlie the grazing legacy effects and the interactions with fencing and moderate grazing.

Contrasting Effects of Tectonic Faults on Vegetation Growth along the Elevation Gradient in Tectonically Active Mountains

Long-term tectonic movements have shaped the geomorphological features and hydrothermal conditions of mountains, influencing their vegetation growth patterns in both positive and negative ways. However, little is known about the effect of fault development on the spatio-temporal variation in vegetation along the elevation gradient in mountainous regions. To address this issue of montane tectonic ecology, this study selected the tectonically active mid-altitude zone (1000–3500 m) of the Chinese Western Tianshan Mountains. The role of tectonics is investigated by fault length density maps calculated from zonal statistics of region-scale fault survey data (1:250,000). The normalized difference vegetation index (NDVI) was chosen as an indicator to analyze the growth status of vegetation. The spatial distribution of fault length density, elevational, and interannual characteristics of the NDVIs from 2000 to 2020 and their relationships along the elevation gradient were investigated. The results show that the faulting zone accounts for 32.6% of the study area and the high faulting zone exhibits a unimodal distribution along the elevation gradient, with the maximum occurring at elevations of approximately 2000 m. The NDVIs of forests and high-coverage grassland show a unimodal distribution with elevation, with the maximum occurring at elevations of approximately 2000 m, coinciding with that of fault length density. In the elevation range of 1000–2500 m, the NDVI of the faulting zone is lower than that of the non-faulting zone, whereas that of the elevation range of 2500–3500 m is higher—a difference that is particularly evident in forests. This elevation-dependent contrasting effect of faults on vegetation growth could be attributed to more favorable hydrothermal conditions for vegetation in fault valleys and reduced landslide susceptibility with increasing elevation. This study highlights the need to consider fault distribution in understanding vegetation distribution and growth in tectonically active mountains.

Nicotinamide Prevents Retinal Vascular Dropout in a Rat Model of Ocular Hypertension and Supports Ocular Blood Supply in Glaucoma Patients.

To investigate whether nicotinamide (NAM) modulates retinal vasculature in glaucoma. This was a prospective controlled clinical trial investigating animal and human histopathology. Participants included normotensive and ocular hypertensive rats, postmortem human ocular tissue, glaucoma patients (n = 90), and healthy controls (n = 30). The study utilized histopathology, computer-assisted retinal vasculature analysis, optical coherence tomography angiography (OCTA), and NAM treatment. The main outcome measures included retinal vascular parameters in rats as assessed by AngioTool; retinal vasculature integrity in rats and humans as assessed by histopathology, antibody-staining, and ImageJ-based measurements; and retinal perfusion density (PD) and flux index in humans as assessed by OCTA. A number of vessel parameters were altered in ocular hypertension/glaucoma compared to healthy controls. NAM treatment improved the retinal vasculature in ocular hypertensive rats, with an increase in mean vessel area, percentage area covered by vessels, total vessel length, total junctions, and junction density as assessed by AngioTool (all P < 0.05); vessel wall integrity as assessed by VE-cadherin antibody staining was also improved (P < 0.01). In humans, as assessed by OCTA, increases in PD in the optic nerve head and macula complete image (0.7%, P = 0.04 and 1.0%, P = 0.002, respectively) in healthy controls, and an increase in the temporal quadrant of the macula (0.7%, P = 0.02) in glaucoma patients was seen after NAM treatment. NAM can prevent retinal vascular damage in an animal model of glaucoma. After NAM treatment, glaucoma patients and healthy controls demonstrated a small increase in retinal vessel parameters as assessed by OCTA.

Research on the mechanism of plant root protection for soil slope stability.

In order to investigate the impact of herbaceous root development on soil slope stability in expansive soil areas, the research was conducted in the soil slope experimental area of Yaoshi Town, Shangzhou District, Shangluo City. Three types of herbaceous plants, namely Lolium perenne, Medicago, and Cynodon dactylon, were planted to examine their influence on slope stability. The results indicated that Lolium perenne had significantly higher root length density and root surface area density compared to Cynodon dactylon and Medicago. However, the root weight density of Cynodon dactylon was found to be highest. The roots of Lolium perenne, Cynodon dactylon, and Medicago were predominantly observed in diameter ranges of 0 < L ≤ 1.0 mm, 0 < L ≤ 2.5 mm, and 2.5 < L ≤ 3.0 mm, respectively. The roots of herbaceous plants have the ability to enhance water retention in soil, resist hydraulic erosion of slope soil, and reduce soil shrinkage and swelling. During the initial phase of herbaceous planting, there is an accelerated process of organic carbon mineralization in the soil. The roots of herbaceous plants play a crucial role in soil consolidation and slope protection. They achieve this by dispersing large clastic particles, binding small particles together, altering soil porosity, enhancing soil water retention, and reducing soil water infiltration. It was found that Lolium perenne and Medicago, which have well-developed roots, exhibited superior slope protection effects. These findings contribute to the theoretical understanding for the implementation of green ecological protection technology on soil slopes.

Association of Male Sex and Microvascular Alterations on Optical Coherence Tomography Angiography in Diabetes.

Epidemiologically, men have a higher incidence, severity, and progression of diabetic retinopathy (DR) than women. We investigated microvascular differences between men and women with diabetes on optical coherence tomography angiography (OCTA). Three × 3 mm OCTA macula scans of non-diabetic and patients with diabetes were obtained. Vascular parameters included parafoveal vessel density (VD), vessel length density (VLD), and flow index (FI) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) as well as foveal avascular zone (FAZ) area and perimeter. Multivariable linear regression was used for statistical analysis. There were 1809 patients with diabetes and 217 non-diabetic participants that were included in this study. Diabetic individuals included those with no DR (n = 1356), mild non-proliferative DR (NPDR; n = 286), moderate NPDR (n = 126), and severe NPDR/proliferative DR (PDR; n = 41). Male sex was significantly associated with smaller FAZ area/perimeter and lower DCP VLD in both non-diabetic subjects and patients with diabetes. Male sex in the diabetic group was additionally associated with lower SCP VD/VLD and DCP VD. Addition of an interaction between male sex and diabetes status in the interaction analysis showed that being male and diabetic conferred increased reduction in DCP VD and VLD compared to sex-based changes in non-diabetics. Larger FAZ perimeter, lower SCP VD/VLD, and lower DCP VLD were associated with poorer visual acuity in diabetics. On OCTA, male patients with diabetes may have more severe microvascular disease especially in the DCP compared to women. Sex-based alterations in diabetic microvascular disease has the potential to influence future basic and clinical studies as well as the implementation of OCTA disease markers.

Quantification of tiny damage variation in asphalt mixture during the low-temperature thermal cycle

The performance evaluation of asphalt materials during low-temperature thermal cycles remains a challenge, particularly in quantifying the early tiny damage development and recovery processes. To address this issue, a high-sensitivity nonlinear ultrasonic method - the second harmonic generation (SHG) technique in the form of Rayleigh surface waves, is proposed to investigate these behaviors in asphalt mixture. The decrease in thermal contraction value and stiffness modulus with cycles verifies the damage behavior at the macro level. Turning points in crack length, crack density, and nonlinear parameter during the thermal cycle indicate the generation of cracks from − 20 ℃ to − 30 ℃ during the cooling process. The decrease of crack length and crack density in the heating phase demonstrates the recovery of asphalt. The nonlinear ultrasonic parameter β'(c) caused by crack is successfully separated from the total nonlinear parameter β', and the recovery index (RI)is defined to quantify the recovery behavior. Both of them are highly consistent with crack length and crack density. While the sensitivity index (SI) of nonlinear parameter is hundreds or thousands of times greater than other measurements of damage development. Furthermore, a qualitative correlation between the nonlinear parameters and plastic strain has been established. This breakthrough widens the scope of studying low-temperature weak damage in asphalt mixtures, moving beyond the confines of crack analysis.

Chronic Effects of e-Cigarette Aerosol Inhalation on Macular Perfusion Assessed Using OCT Angiography.

Purpose: To determine whether there are significant differences in the microvasculature and central retinal thickness (CRT) between e-cigarette users (user group) and age-matched nonusers (control group) using optical coherence tomography angiography (OCTA). Methods: In this prospective cross-sectional observational study, OCTA images were acquired of 52 eyes of 26 users and 25 eyes of 25 age-matched nonusers. Daily e-cigarette users with no ocular history were identified from provider information in the electronic medical record. A custom algorithm was used to calculate the foveal avascular zone (FAZ), vessel area density (VAD), and vessel length density (VLD). OCT software was used to calculate the foveal, superior, inferior, nasal, and temporal CRT. Generalized estimating equations using the Z-statistic were used to determine how the FAZ, VAD, VLD, and CRT parameters varied between groups and to assess the differential contribution of descriptive data in the user group. Results: No statistically significant difference was found between the user group and control group in the FAZ, superficial vascular complex (SVC) VAD, SVC VLD, or deep vascular complex (DVC) VAD. A statistically significant difference was found for DVC VLD (P = .002), with the user group having a slightly higher VLD on average. Superior, temporal, and inferior inner macular thicknesses were significantly thinner in the user group (P = .038, P = .012, and P = .035, respectively). Conclusions: Significant negative differences were found in CRT measures but not in retinal microvasculature parameters between e-cigarette users and nonusers. Decreased inferior, temporal, and superior inner macular thickness in e-cigarette users may show an early chronic structural effect that warrants further assessment of retinal effects as this population ages and continues to use e-cigarettes.

Improved microstructure and strength of Sn-Ag-Cu/Cu solder joint with Mo nanoparticles addition

A new type of lead-free composite solder has been prepared by adding Mo nanoparticles in Sn3.0Ag0.5Cu solder. Tensile strength tests were conducted on Sn3.0Ag0.5Cu/Cu joint and composite solder/Cu joints. The results indicated that the addition of Mo nanoparticles markedly improved the tensile strength of solder joint. when Mo concentration was between 0 and 1%, with the increase of Mo concentration, the tensile strength increased significantly. EBSD (Electron Back Scatter Diffraction) analysis of microstructure was conducted. It was concluded that Mo could significantly increase grain boundary length and dislocation density, reduce the size of the β-Sn phase.

Fall/winter cover crop roots change soil hydrology to control the drought status of subsequent season summer maize in Ultisol

Climate change has increased drought frequency, necessitating strategies to reduce water stress, increase water use efficiency, and improve agricultural productivity. The impacts of different fall/winter cover crops on alleviating maize drought in the subsequent season by changing soil water content remain unclear in Ultisol. Our aim was to investigate whether different fall/winter cover crops (taproot and fibrous root) can improve soil water content to attenuate subsequent season maize drought and its underlying mechanism. This research compared four fall/winter cover crops (2 rapeseed cultivars, lucerne and vetiver) and fallow control (no cover crop in winter) to investigate their root traits, root effect on subsequent season soil water content (SWC), soil drought degree (D), maize leaf and root water potential (Ψl, Ψr), maize crop water stress index (CWSI), and maize growth components (aboveground plant and root parameters) in 2019 (a dry year), 2021 (a normal wet year), and 2022 (a severe dry year). The fibrous-rooted vetiver displayed higher average root diameter and higher average root length density, leading to increased SWC (17%, 15%, 15%), and lower D values in all three years. Additionally, it exhibited a more substantial gradient between Ψl, and Ψr and lower CWSI than taproot (rapeseed cultivars and lucerne) and fallow treatment. Furthermore, the cover crop treatments enhanced the gradient between maize Ψl and Ψr to varying degrees in different drought years. Ultimately, the improvement in SWC resulting from cover crop treatments increased maize aboveground growth (plant height, stem diameter, and leaf area) and maize root development, ultimately improving maize yield. This study introduces a new perspective on investigating the role of cover crops in alleviating seasonal drought in subsequent crops, especially by changing soil water properties in the subtropical climate.

Fine-root morphology of woody and herbaceous plants responds differently to altered precipitation: A meta-analysis

The growth of plant roots and their acquisition of resources are significantly impacted by changes in precipitation patterns. Although numerous studies have examined the impact of precipitation on fine root systems, the rooting strategies of woody and herbaceous plants under different precipitation patterns remain to be comparatively evaluated. Accordingly, in the current study, we conducted a meta-analysis of 64 peer-reviewed articles to explore the response of 17 biomass and fine-root traits of woody and herbaceous plants to precipitation changes. Our findings demonstrate that woody and herbaceous plants have developed different root strategies to cope with altered precipitation. Specifically, when precipitation increased, the fine roots of woody plants had a larger surface area and significantly increased shallow root growth. In contrast, the fine-root morphological traits of herbaceous plants showed a stronger response to increased precipitation, in which fine-root length, volume, and tissue density increased. This may result in more effective use of available water by herbaceous than woody plants. When precipitation decreased, woody plants displayed more active fine-root morphological alterations, presenting a conservative fine-root phenotype of resource acquisition, with lower specific root length and higher fine-root tissue density. Moreover, woody plants transfer absorptive fine-root structures to deep soil layers, whereas herbaceous plants are less drought-tolerant. Furthermore, woody plants may allocate biomass more optimally than herbaceous plants in precipitation-reduction scenarios. Increased precipitation may boost soil carbon sequestration and stability in woody plant-dominated forest ecosystems under future climate change scenarios, while drought may considerably reduce soil carbon storage in grassland ecosystems. In more arid environments, where woody and herbaceous plants coexist, drought may lead to the expansion of woody plants and subsequent predominance of woody plants vegetation change. our findings will fill knowledge gaps in the literature regarding the effects of precipitation changes on the fine-root dynamics of various functional plants and will improve predictions of the vegetation dynamics of forests, grasslands, and other ecosystems vegetation dynamics under changing precipitation patterns.

Corneal characteristics of Mongolian population with type 2 diabetic peripheral neuropathy in inner Mongolia, China: an assessment using corneal confocal microscopy

ObjectiveTo quantify corneal nerve fiber parameters in a Mongolian population with diabetic peripheral neuropathy (DPN) by corneal confocal microscopy.MethodsThis study conducted a comprehensive evaluation of 114 participants from Hulunbuir between January 2020 and December 2021. The participants included healthy controls, Mongolian and Han patients with type 2 diabetes mellitus. Demographic, medical, and laboratory data were collected, and neuropathy was evaluated by confocal corneal microscopy. And compare various parameters between Han and Mongolian were performed using SPSS software.ResultsThe average waist circumference of Mongolian diabetic patients was larger than that of Han diabetic patients (P < 0.05). The mean HbA1c of Mongolian was 9.30 (8.15, 10.30) %, and that of Han was 8.30 (7.20, 9.40) % (P = 0.023). The average values of Corneal Nerve Fiber Density (CNFD), Corneal Nerve Fiber Length (CNFL) and corneal nerve branch density (CNBD) in Mongolian diabetic patients were significantly lower than those in Han diabetic patients (P < 0.05). The correlation coefficient between CNFL and age was − 0.368. ROC results show that CNBD has a certain diagnostic value for DPN in Mongolian patients with type 2 diabetes and the optimal cut-off point value is 24.99(no./mm2), the sensitivity is 80.0%, and the specificity is 77.8%.ConclusionThe corneal confocal microscopy could possibly represent a promising adjuvant technique for the early diagnosis and assessment of PDN in Mongolian T2DM patients.

Impact of roots on the hydrogeological properties of silty soil covers

Mine tailings storage poses significant environmental risks such as the formation of acid mine drainage. Engineered covers offer a solution by controlling water ingress. Their performance is based on specific soil hydrogeological properties (SHPs). They must support vegetation which can impact saturated hydraulic conductivity ( ksat) and water retention curve (WRC). This study assesses the impact of 4-year-old willow root colonization on silty soil covers using flexible wall parameters and water retention tests. The obtained SHPs were compared with root traits. The results suggested that the hydrogeological properties of the studied in situ samples were not significantly affected by roots. The variation of measured and predicted ksat values spanned an order of magnitude, regardless of the root colonization intensity, up to a root length density (RLD) of 2.98 cm/cm3. RLD showed a significant and positive linear relationship with measured ksat values ( R2 = 0.54). However, when root colonization was low (RLD &lt; 1 cm/cm3), RLD was negatively correlated with the nvG ( R2 = 0.44) parameter of the van Genuchten WRC model, while the opposite relationship was observed for samples with RLD &gt; 1 cm/cm3 ( R2 = 0.61). Additionally, RLD and the coarse root (diameter &gt; 1 mm) volume to fine root volume (C/F ratio) influenced WRCs. Over time, coarser roots may have a more pronounced impact on SHPs; further research is needed.

Optimizing water and nitrogen management can enhance nitrogen heterogeneity and stimulate root foraging

ContextThe root development and soil nitrogen distribution in cotton fields under varying water and nitrogen supplies have rarely been reported in Xinjiang, Northwest China. MethodsTo address this gap, a two-year field experiment was conducted during the 2019 and 2020 growing seasons to determine the impact of two irrigation amounts (I400, conventional irrigation, 400 mm; and I267, limited irrigation, 267 mm) and three N fertilizer rates (N320, 320; N272, 272; and N224, 224 kg N ha−1) on the soil NO3-N distribution, root distribution, aboveground nitrogen accumulation, and water and nitrogen use efficiency. ResultsUnder the I400 condition, soil NO3-N exhibited a 30.4% higher horizontal heterogeneity in the N272 plots compared to the N320 plots. The root length and number in the N272 plots increased by 29.0% and 85.0%, respectively, compared with those in N320. Additionally, the N272 plots exhibited higher root length density and root dry weight in the 40–80 cm soil layers. These advantages of the N272I400 combination resulted in the highest seed cotton yield, nitrogen accumulation, and nitrogen use efficiency. Under the I267 condition, the N320 plots showed significantly increased yield and aboveground N content, enhanced horizontal soil NO3-N heterogeneity, and substantially accelerated root growth in deep soil compared with the N reduction plots. A quadratic correlation was observed between root length and soil NO3-N content. Root length was positively correlated with nitrogen accumulation in aboveground leaves and negatively correlated with soil NO3-N residue. These findings suggest that enhancing the development and distribution of roots promotes plant nitrogen accumulation and photosynthesis and facilitates the soil NO3-N absorption. ConclusionsIn conclusion, nutrient heterogeneity can enhance nutrient uptake and improve plant performance, which have important implications for plant productivity and ecosystem functioning.

Abstract 12907: Aging Drives Cerebrovascular Network Remodeling and Functional Changes in the Mouse Brain

Introduction: Cerebrovascular dysfunction has been implicated in age-related cognitive decline and dementia, but the underlying vascular mechanisms are not well understood. An improved understanding of the nature of normal cerebrovascular aging is needed to help to establish the role that vascular dysfunction might play in cognitive decline and dementia. Methods: Here, we asked how normal aging differentially impacts the vascular structure and function in different brain areas in mice. We investigated structural changes in aged cerebrovascular networks and pericytes utilizing serial two-photon tomography (STPT). To further investigate potential remodeling of different vascular compartments and pericyte subtypes, we utilized tissue clearing, 3D immunolabeling, and light sheet fluorescence microscopy (LSFM) imaging. We also assessed how healthy aging impacts brain hemodynamics in response to voluntary locomotion and whisker stimulation in awake, head-fixed mice using wide field optical signal imaging and two-photon imaging. We tested mice of both sexes at 2-month, 18-month (early aging), and 24-month (late aging) of age. Results: Whole-brain vascular tracing using STPT showed an overall ~10% decrease in vascular length and branching density, and LSFM imaging with 3D immunolabeling further revealed increased arteriole tortuosity in aged brains. We also uncovered a selective vascular and pericyte loss in deep cortical layers, basal forebrain regions, and the hippocampal network. This may contribute to their regional vulnerabilities in neurodegenerative disorders. Moreover, our in vivo imaging in awake, head-fixed mice identified delayed neurovascular coupling response and inefficient oxygen delivery in aged brains. Conclusions: Our study reveals aging-related brain-wide changes in vascular and mural cell types that can explain vulnerability and resilience of different brain areas in normal aging. Moreover, we identified an age-related decrease in brain oxygenation and delayed neurovascular coupling responses which can be linked with cognitive impairment in aged brains. These aging-related changes will serve as a common factor to understand many neurodegenerative disorders and cognition decline in the elderly population.