Mean Vessel Area Research Articles

Variation in functional traits among different mycorrhizal types and life history stages of temperate broadleaf tree species

Exploring the variation in functional traits in plants from different perspectives not only helps reveal the adaptation of plants to their environment but also reflects the ecological strategies of plants. In this study, three species of arbuscular mycorrhizal (AM) trees and three species of ectomycorrhizal (EM) trees were selected in the Heilongjiang Liangshui National Nature Reserve. To investigate the similarities and differences between the functional traits of the two mycorrhizal types of trees at different life history stages, hydraulic traits, anatomical traits, leaf functional traits, and stoichiometry of each species were measured at different life history stages. Traits such as mean vessel area, hydraulic weighted vessel diameter and nitrogen content appeared to be relatively important traits in this study, and all traits were more strongly correlated in AM trees. The sapwood-specific hydraulic conductivity, leaf-specific hydraulic conductivity, vessel density, vessel lumen fraction, nitrogen content and phosphorus content of EM species were significantly higher than those of AM species, while the total vessel area, mean vessel area, hydraulic weighted vessel diameter and density of primary leaf veins of EM species were significantly lower than those of AM species. The leaf mass per area and leaf dry matter content of saplings were significantly lower than those of juvenile trees and adult trees. Most of the trait variation interspecific and intraspecific, and the variability of hydraulic and anatomical traits such as sapwood-specific hydraulic conductivity, leaf-specific hydraulic conductivity, vessel density and total vessel area was relatively large. Leaf dry matter content, hydraulic weighted vessel diameter, vessel density and the vessel lumen fraction contributed significantly to whole branch hydraulic conductivity. It is evident that plastic adjustment and synergistic variation in functional traits are important mechanisms by which plants with different mycorrhizal types and at different life history stages can adapt to different environments.

Site-specific climate sensitivity of tree-ring width and vessel anatomical features of Juglans regia L. in Bhutan Himalaya

Climate change significantly impacts tree growth in the Himalayas, however, there is little information on how broadleaved tree species in Himalayan regions respond to climate change. Juglans regia L. (Common or Persian walnut) plays a vital economic and ecological role across the Himalayas, but little is known about how environmental changes influence the growth and wood anatomical traits of this species. In this study, we developed chronologies of tree-ring width (TRW) and six quantitative vessel anatomical features of Persian walnut trees from two sites in the Bhutan Himalayas. We evaluated how TRW and vessel anatomical features respond to climatic conditions and extreme climate events for the period 1960–2020. We found the climate sensitivity of tree growth differed at the two study sites, with the southwest-facing Dodeyna site (DOD) exhibiting higher moisture sensitivity than the north-facing Chimithangka site (CHI). The climate sensitivity of vessel traits was much stronger than that of tree-ring widths, particularly at the DOD. Hydraulic efficiency-related vessel traits (Mean vessel area, MVA; theoretical hydraulic conductivity, Kh; and hydraulic diameter, Dh) were positively sensitive to moisture availability, whereas the hydraulic safety-related vessel traits (vessel density, VD; and vessel grouping index, RVGI) were negatively sensitive to moisture availability at the DOD site. We further observed that MVA and Kh were significantly higher during extreme dry events at CHI site but displayed opposite directions at DOD site. Notably higher RVGI at the DOD site during dry years indicated an enhancement of hydraulic safety against drought. These findings highlight that the climate sensitivity of tree-ring width and vessel traits of walnuts were site-specific and mediated by aspects with the drier site (south-facing slope) being more sensitive. Whilst consideration of the aspects and site-specific climate sensitivity of tree species is crucial to developing robust forest conservation strategies at a larger spatial scale in the Himalayan region which is more vulnerable to climate change.

Xylem adjustment and growth response of early- and late-successional tree species to rapid warming

Climate changes have dramatically affected forest succession. However, how trees at different successional stages respond to climate warming is unclear in the subtropics. Here, we compared the radial growth (RW) and xylem features of the early-successional stage Castanea mollissima and late-successional stage Quercus fabri in subtropical forests and assessed their response to climate changes. All parameters, including RW, number of vessels (VN), vessel density (VD), mean (MVA) and total (TVA) vessel area, percentage of conductive area within xylem (RCTA), theoretical (Kh) and xylem-specific (Ks) hydraulic conductivity, except for MVA of C. mollissima were significantly higher than those of Q. fabri. During the drought period, a notable adverse correlation between two cluster parameters of Q. fabri, associated with hydraulic safety and efficiency, suggested a pronounced hydraulic trade-off in Q. fabri under drought conditions. Castanea mollissima was more sensitive to climate and more prone to hydraulic failure than Q. fabri. Temperatures and moisture conditions positively and negatively affected the hydraulic efficiency-related parameters of C. mollissima. Moisture conditions in the previous summer and winter were significantly negatively and positively related to the radial growth of both species. The impact of generalized warming was not evident due to variations in hydraulic strategies and species characteristics, trade-offs between non-growing and growing season climates, and specific competition. If climate warming continues, C. mollissima growth will probably significantly decline due to the increasing risk of hydraulic failure. Warming may accelerate species replacement and forest succession in the study area by changing their lifespans and competitive relationships.

Different patterns of inter-annual variability in mean vessel area and tree-ring widths of beech from provenance trials in Slovenia and Hungary

Key messageStudied beech provenances showed different patterns of inter-annual variability in mean vessel area and ring widths, indicating influence of intraspecific variability and diverse environment on hydraulic conductivity and carbon storage potential.International provenance trials of ecologically and economically important tree species are crucial to deciphering the influence of environmental factors and intraspecific variability on tree growth and performance under climate change to guide assisted gene flow and assisted migration of tree provenances and species. In this context, we compared inter-annual trends in tree-ring widths (carbon sequestration potential) and vessel characteristics (conductivity optimisation) of four beech provenances in two international provenance trials, one in Slovenia (Kamenski hrib, a core beech growing site) and one in Hungary (Bucsuta, a marginal beech site) in 2009–2019. We found different patterns of inter-annual variability in mean vessel area and tree-ring widths among provenances and sites, pointing to diverse genetic background and environmental influence on these two wood-anatomical traits. The average values of the vessel area varied less between provenances at Kamenski hrib than at Bucsuta. Weather conditions differently affected tree-ring width and mean vessel area. Furthermore, the length of the period of response of vessel area to the analysed weather conditions differed in summer and winter periods. The differences in the mean vessel area within the tree ring were more pronounced in the weather-wise extreme years, regardless of the provenance. Consistent with previous studies, we confirmed that site conditions affect the climate sensitivity of trees, which is more pronounced at marginal sites or in extreme years. The findings on how different environmental conditions affect the radial growth of young beech trees of different origin are very important for future forest management.

Impact of Environmental Conditions on Wood Anatomical Traits of Green Alder (Alnus alnobetula) at the Alpine Treeline

Due to land use change, green alder (Alnus alnobetula), formerly restricted to moist slopes, is now expanding to drier sun-exposed sites at the alpine treeline. The highly productive shrub is forming closed thickets, establishing nitrogen-saturated species poor shrublands. To evaluate wood anatomical adaptations to changing environmental conditions, we analyzed vessel characteristics (mean vessel area, MVA; vessel density, VD; and theoretic conductive area, TCA) and axial parenchyma abundance, as well as their distribution in the annual ring at a moist north-facing and a dry south-facing site at the alpine treeline on Mt. Patscherkofel (Central European Alps, Austria). Results revealed that lower soil water availability and enhanced evaporative demand did not affect MVA while VD and TCA were significantly reduced at the dry south-facing site. This suggests that in green alder, vessel size is a static trait whereas vessel number responds plastic. Limited water availability also triggered a significant increase in axial parenchyma, confirming the important role of xylem parenchyma in water relations. Harsh environmental conditions at the distributional limit of green alder may have affected xylogenesis, leading to a near semi-ring-porous distribution of vessels and an accumulation of parenchyma in the late growing season. We conclude that in a warmer and drier climate, growth limitation and physiological stress may set limits to the distribution of Alnus alnobetula at drought-prone sites in the alpine treeline ecotone.

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.

Species with larger vessel area have higher bias for the original Granier equation in calculating sap flux density

Accurate estimate of transpiration is crucial to understanding global water and carbon cycles. The thermal dissipation (TD) method with Granier’s equation, which is the most popular approach to measure whole-tree water use, requires species-specific calibration parameters to calculate transpiration. Calibrations require direct measurement of water uptake, often through gravimetric or potometric methods; therefore, it is often disregarded because of limited time and resources. It remains unclear which factor influences the variation of calibration parameters. In this study, we compiled published calibration experiments to elucidate the factors that could influence the variation in coefficients and attempted to predict the correction parameter. The results showed that: (1) only 14 % of the experiments provided accurate sap flux density estimates using the default parameter values in the Granier’s equation, and sap flux was underestimated to varying degrees in 72% of the experiments; (2) the regression slope of TD-measured and the actual sap flow with the y-axis intercept set to zero (hereinafter referred to as “Slope”) was significantly correlated to the mean vessel area (VA), i.e., species with larger VA consistently had higher Slope and greater bias. Stem diameter also had a positive influence on the Slope after accounting for covariation with the VA. Finally, a multiple linear regression model based on these two characteristics (VA and stem diameter) explained 89% of the variation of Slope. This study provides a simple calibration procedure for the users of TD-sensors with a linear correction model based on easily measurable vessel area and stem diameter. It may also provide a new development avenue for sensor manufacturers or others to improve the TD method to reduce its sensitivity to wood characteristics – or provide some “out-of-the-box” correction factors across a range of wood characteristics.

10 Preliminary Effect of Cottonseed as a Source of Gossypol on Hepatic Portal Blood Flow as an Indicator of Metabolism in Meat does Artificially Infected withHaemonchus Contortus

Abstract Cottonseed diets provide animals with increased levels of protein and energy to support growth. Recently, it was suggested that although the gossypol content of cottonseed could result in adverse animal reproduction, it could have a potential anthelmintic property beneficial to small ruminant operations. In addition, gossypol is primarily cleared and excreted from the animal via liver glucuronidation, which is a primary pathway for steroid clearance in ruminants. The objective of this experiment was to determine the effect of a cottonseed diet and parasite load on the hepatic portal blood flow an indicator of hepatic clearance rates and metabolism. Forty Boer x Spanish cross does were assigned to of 4 treatments (n = 10 per treatment group) in a 2x2 factorial design consisting of cottonseed supplementation and no parasite infection (CNP), cottonseed supplementation plus artificial infection with Haemonchus contortus (CP), commercial pellets with no parasite infection (NCNP), or commercial pellets plus artificial infection with Haemonchus contortus (NCP). On week 8 post-treatment, hepatic portal blood flow measurements were collected via Doppler ultrasonography on the right side of the animal at the 10th intercostal space. Blood flow was then calculated using the following equation: blood flow (mL/min) = mean velocity (cm/s) x vessel area x 60 seconds. The mean velocity was calculated by the following formula: (systolic – diastolic)/pulsatility index. Hepatic portal blood flow and body weight of does were analyzed with a One-way ANOVA using the MIXED procedure of SAS with diet and parasite load as the main effects and their interactions. A diet by parasite interaction (P = 0.026) was observed for the mean velocity of the hepatic portal vein, which was decreased in CP versus CNP treatments. A diet by parasite interaction (P = 0.012) was observed for the diameter of the hepatic portal vein, which was increased in the CP treatment versus all other groups. However, absolute hepatic portal blood flow was not different (P &amp;gt; 0.12) amongst treatments. A tendency for the main effect (P = 0.087) of diet was observed for hepatic portal blood flow relative to body weight, which was an increase in cottonseed (27.8 ±.8 mL/min*kg) versus NCS (23.2 ±.8 mL/min*kg). Body weight was not different (P &amp;gt; 0.35) amongst treatments at the time of Doppler ultrasound examination. In conclusion, cottonseed interacted with parasites to decrease mean velocity and increase the diameter of the portal vein. In addition, cottonseed appears to increase liver blood flow relative to body weight. This change in relative liver blood flow could have implications for mediating hepatic metabolism and clearance.

锡林浩特多年生草本根部导管性状与植株生态策略的相关特征

PDF HTML阅读 XML下载 导出引用 引用提醒 锡林浩特多年生草本根部导管性状与植株生态策略的相关特征 DOI: 10.5846/stxb202108262399 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重大项目（41991233）；国家自然科学基金面上项目（41877539，42071125） Vessel traits of main roots are linked to ecological strategies of the perennial herbs in Xilinhot of China Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:干旱半干旱区植物的木质部输水系统对维持植物生长发育有重要作用。以中国干旱半干旱区的草本植物为研究对象，旨在探究草本物种根系导管解剖结构与植物生长之间的关系。用石蜡切片法，将在锡林浩特草原采集的草本物种的主根样品制作成切片，得到固定面积内导管解剖结构参量（导管数量、导管分数、平均导管面积、平均水力传导率和水力直径），然后用逐步回归法和Pearson相关分析各导管解剖性状与植物生长特征（年龄、生长速率和平均高度）之间的关系。结果发现（1）生长速率与导管数量（R=-0.494，P<0.01）和导管分数（R=-0.255，P<0.05）显著负相关，与平均导管面积（R=0.274，P<0.05）、平均水力传导率（R=0.263，P<0.05）和水力直径（R=0.245，P<0.05）显著正相关，表明生长快的草本具有大而少的导管，需要较高的水分传输能力，而生长慢的草本具有小而多的导管，水力安全性较高；（2）植株的高度与导管数量（R=-0.354，P<0.01）显著负相关，与平均导管面积（R=0.293，P<0.05）、平均水力传导率（R=0.289，P<0.05）和水力直径（R=0.278，P<0.05）显著正相关，表明高大的植株以较少的导管补偿较大的导管以维持一定的机械强度，而矮小植株的水力安全性较高。 Abstract:The hydraulic system plays an important role in supporting plant growth and development in arid and semiarid regions. In this study, we explored the relationship between vessel anatomical traits and growth characteristics of herbaceous species. We used paraffin sectioning method to make taproot sections, and acquired the characteristics of vessel anatomical structures (including number of vessels, vessel fraction, mean vessel area, mean hydraulic conductivity, and hydraulic diameter) in a fixed area. Pearson correlation and stepwise regression methods were used to analyze the relationship between vessel anatomical traits and plant growth characteristics (age, growth rate, and mean height). The results indicated that (1) the growth rate was significantly negatively correlated with vessel number (R=-0.494, P<0.01) and vessel fraction (R=-0.255, P<0.05), whilist, significantly positively correlated with mean vessel area (R=0.274, P<0.05), mean hydraulic conductivity (R=0.263, P<0.05), and hydraulic diameter (R=0.245, P<0.05), which may indicate that fast-growing herbs form larger and fewer vessels to increase the hydrualic efficiency, while slow-growing herbs form smaller and more vessels to increase hydraulic safety. (2) Mean height was significantly negatively correlated with vessel number (R=-0.354, P<0.01), whilist, significantly positively correlated with mean vessel area (R=0.293, P<0.05), mean hydraulic conductivity (R=0.289, P<0.05), and hydraulic diameter (R=0.278, P<0.05), which may suggest that in order to maintain the mechanical strength, high plants usually form few vessels to compensate for large vessels, while short plants form smaller and more vessels to increase hydraulic safety. 参考文献 相似文献 引证文献

Further Evidence of Neuroprotective Effects of Recombinant Human Erythropoietin and Growth Hormone in Hypoxic Brain Injury in Neonatal Mice.

Experimental in vivo data have recently shown complementary neuroprotective actions of rhEPO and growth hormone (rhGH) in a neonatal murine model of hypoxic brain injury. Here, we hypothesized that rhGH and rhEPO mediate stabilization of the blood–brain barrier (BBB) and regenerative vascular effects in hypoxic injury to the developing brain. Using an established model of neonatal hypoxia, neonatal mice (P7) were treated i.p. with rhGH (4000 µg/kg) or rhEPO (5000 IU/kg) 0/12/24 h after hypoxic exposure. After a regeneration period of 48 h or 7 d, cerebral mRNA expression of Vegf-A, its receptors and co-receptors, and selected tight junction proteins were determined using qRT-PCR and ELISA. Vessel structures were assessed by Pecam-1 and occludin (Ocln) IHC. While Vegf-A expression increased significantly with rhGH treatment (p < 0.01), expression of the Vegfr and TEK receptor tyrosine kinase (Tie-2) system remained unchanged. RhEPO increased Vegf-A (p < 0.05) and Angpt-2 (p < 0.05) expression. While hypoxia reduced the mean vessel area in the parietal cortex compared to controls (p < 0.05), rhGH and rhEPO prevented this reduction after 48 h of regeneration. Hypoxia significantly reduced the Ocln+ fraction of cortical vascular endothelial cells. Ocln signal intensity increased in the cortex in response to rhGH (p < 0.05) and in the cortex and hippocampus in response to rhEPO (p < 0.05). Our data indicate that rhGH and rhEPO have protective effects on hypoxia-induced BBB disruption and regenerative vascular effects during the post-hypoxic period in the developing brain.

Disparate response to water limitation for vessel area and secondary growth along Fagus sylvatica southwestern distribution range

The response of European beech (Fagus sylvatica L.) to climate warming will depend on the ability of their populations to adjust tree performance to water shortage. By exploring inter- and intra-annual variations in secondary growth and mean vessel area (MVA), we assessed the effects of precipitation on cambial activity and hydraulic control during the vessel expansion phase along tree lifes. We sampled beech populations at low and high altitude from four mountain ranges across its southwestern distribution edge. We measured a total of 45,897 rings from 126 trees and 5.5 million vessels from 76 trees. We built chronologies for ring width and MVA between 1950 and 2017, calculated their climate responses and evaluated the effects of region, altitude and chronology type (ring-width vs. MVA) by means of ordinations (PCA) and constrained ordinations (pRDA). Precipitation controlled ring width and MVA along beech's southwestern distribution range, but at different time domains. Ring width responded primarily to summer precipitation during the previous growing season, whereas MVA responded to water availability during the vessel expansion phase, with timing shifting along the ring, according to the moment of vessel expansion. Regional differences were significant, but low, compared with the effect of chronology type. A large part of the variance explained by region was due to the strong difference between Western Pyrenees forests –growing under hyperhumid conditions– and the rest of forests under drier and warmer climate. Only minor differences between altitudes were found for the climate control of ring width and vessel size at annual scale, and no intra-annual effect on climate control of MVA. The stronger effect of chronology type on climatic response compared to the role of geographical location or altitude suggests common climate constraints on secondary growth and xylem anatomy along beech dry edge.

Different-Sized Vessels of Quercus variabilis Blume Respond Diversely to Six-Year Canopy and Understory N Addition in a Warm-Temperate Transitional Zone

Nitrogen is a necessary macroelement in plant growth and is usually considered a limiting factor in many forest ecosystems. Increasing N deposition has been reported to affect tree growth. However, the effects still remain controversial due to variable N fertilization methods used. In order to study the realistic responses of tree growth to increasing N deposition, we investigated effects of canopy and understory N addition on tree-ring growth and vessel traits of Quercus variabilis Blume. Since 2013, 50 kg N ha−1 year was applied monthly from April to December to either the canopy (CN) or understory (UN) of trees in a warm-temperate forest in Central China. During 2013–2018, tree-ring growth and vessel-related traits (mean vessel area, theoretical xylem hydraulic conductivity (KH), relative ratio of KH, etc.) were analyzed. Tree rings were negatively impacted by both CN and UN treatments, but only the effect of UN was significant. Neither CN nor UN significantly impacted the detected vessel traits. However, some diverging influencing trends were still showed in some vessel traits. Both CN and UN treatments positively affected the percentage of annual total vessel area and vessel density, with the effect of UN on vessel density being more severe. All the detected vessel traits of the large vessels formed at the beginning of the tree-ring responded positively to CN, whereas the opposite response to UN was showed on mean vessel area and the relative ratio of KH. All these diverging responses in different vessel traits likely reflected the compensation and trade-off between maximizing growth and adapting to CN and UN treatments. Six-year long N addition negatively and positively affected tree-ring growth and vessel traits of Q. variabilis in Central China, respectively. UN treatment could not fully simulate the real effect on tree growth, especially on the hydraulic architecture.

The intraspecific relationship between wood density, vessel diameter and other traits across environmental gradients

Abstract Wood density (WD), a key trait in the trait‐based approach of plant ecology, represents a carbon investment trait that varies across species and reflects a trade‐off between metabolism and longevity. Across species, WD has been found to vary with phylogeny, moisture, temperature and xylem anatomy (e.g. vessel diameter). However, we know little about WD variation at the intraspecific level. Here, we examined how ecologically important functional traits vary in relation to WD in three generalist, exceptionally wide‐niche breadth tree species from southern Chile, making use of broad precipitation and temperature gradients. We collected branches from Embothrium coccineum and Nothofagus antarctica across a wide W–E precipitation gradient (2,500–600 mm of annual precipitation) and from N. pumilio across an elevational gradient (from low to treeline elevation). For each individual, we determined WD, several xylem anatomical features, for example, mean vessel diameter (MVD), hydraulic diameter (Dh), hydraulic conductivity (Kt), mean vessel area (MVA), vessel size distribution (MVA/VD) and other traits including concentrations of non‐structural carbohydrates (NSCs), secondary growth, leaf traits, water‐use efficiency (iWUE) and growth rate (AI). We quantified the correlation between WD and other traits and evaluated whether WD‐trait relationships differed across species using linear mixed‐effects models. We found consistent and significant negative relationships between WD and several xylem anatomy traits, including Dh, Kt, MVA and MVD. Contrary to our expectations, WD was not related to leaf traits, NSCs, iWUE and AI. Wood density had a significantly negative relationship to MVA/VD (and to a lesser extent, MVD) for both E. coccineum and N. antarctica (the precipitation gradient), while these relationships were positive for N. pumilio (the temperature gradient). Few of the WD and other trait relationships examined at the intraspecific level in this study paralleled those found across species. At the intraspecific level, WD proved to be much more related to xylem anatomical traits than to other traits. Importantly, in some cases, WD‐xylem anatomical trait relationships showed opposite trends depending on the environmental gradient. We must be cautious when using interspecific studies as the basis for inferring trait‐based responses to environmental change across other organisation levels. Read the free Plain Language Summary for this article on the Journal blog.

A Comparative Analysis of the Hydraulic Strategies of Non-Native and Native Perennial Forbs in Arid and Semiarid Areas of China

(1) Background: Water transport systems play an important role in maintaining plant growth and development. The plasticity responses of the xylem anatomical traits of different species to the environment are different. Studies have shown that there are annual growth rings in the secondary root xylem of perennial herbaceous species. Studies on xylem anatomical traits, however, have mainly focused on woody species, with little attention given to herbaceous species. (2) Methods: We set 14 sampling sites along a rainfall gradient in arid and semiarid regions, and collected the main roots of native (Potentilla) and non-native (Medicago) perennial forbs. The xylem anatomical traits of the plant roots were obtained by paraffin section, and the relationships between the xylem traits of forbs were analyzed by a Pearson correlation. (3) Results: In the fixed measurement area (850 μm × 850 μm), the vessel number (NV) of Potentilla species was higher than that of Medicago species, while the hydraulic diameter (Dh) and mean vessel area (MVA) of Potentilla species were lower than those of Medicago species. With the increase in precipitation along the rainfall gradient, the Dh (R2 = 0.403, p = 0.03) and MVA (R2 = 0.489, p = 0.01) of Medicago species increased significantly, and NV (R2 = 0.252, p = 0.09) decreased, while the hydraulic traits of Potentilla species showed no significant trend with regard to the rainfall gradient. (4) Conclusions: The hydraulic efficiency of non-native Medicago forbs was higher than that of native Potentilla forbs, and the hydraulic safety of native Potentilla forbs was higher than that of non-native Medicago forbs. With the decrease in precipitation, the hydraulic strategies of non-native Medicago forbs changed from efficiency to safety, while native Potentilla forbs were not sensitive to variations in precipitation.

Carotid Phase-Contrast Magnetic Resonance before Treatment: 4D-Flow versus Standard 2D Imaging.

The purpose of this study was to evaluate the level of agreement between flow/velocity data obtained from 2D-phase-contrast (PC) and 4D-flow in patients scheduled for treatment of carotid artery stenosis. Image acquisition was performed using a 1.5 T scanner. We compared mean flow rates, vessel areas, and peak velocities obtained during the acquisition with both techniques in 20 consecutive patients, 15 males and 5 females aged 69 ± 5 years (mean ± standard deviation). There was a good correlation between both techniques for the CCA flow (r = 0.65, p < 0.001), whereas for the ICA flow and ECA flow the correlation was only moderate (r = 0.4, p = 0.011 and r = 0.45, p = 0.003, respectively). Correlations of peak velocities between methods were good for CCA (r = 0.56, p < 0.001) and moderate for ECA (r = 0.41, p = 0.008). There was no correlation for ICA (r = 0.04, p = 0.805). Cross-sectional area values between methods showed no significant correlations for CCA (r = 0.18, p = 0.269), ICA (r = 0.1, p = 0.543), and ECA (r = 0.05, p = 0.767). Conclusion: the 4D-flow imaging provided a good correlation of CCA and a moderate correlation of ICA flow rates against 2D-PC, underestimating peak velocities and overestimating cross-sectional areas in all carotid segments.

Early remodeling of the colonic mucosa after allogeneic hematopoietic stem cells transplantation: An open-label controlled pilot study on 19 patients.

BackgroundGraft‐versus‐host disease (GVHD), particularly acute digestive GVHD (aDGVHD), is a severe complication of allogeneic hematopoietic stem cell transplantation (allo‐HSCT). It is necessary to identify predictive factors of GVHD to adapt prophylactic treatment.ObjectiveIn this context, our pilot study aimed (i) to determine whether an early remodeling of the colonic mucosa occurred after allo‐HSCT and (ii) to identify potential predictive mucosal markers of aDGVHD after allo‐HSCT.MethodsBetween day 21 and day 28 after the allo‐HSCT, 19 allo‐HSCT patients were included and had a rectosigmoidoscopy with probe‐based confocal laser endomicroscopy (pCLE) recording and biopsies. Sixteen patients were included in the control group. Morphological (pCLE), functional (intestinal permeability), and inflammatory parameters (cytokine multiplex immunoassay) were assessed.ResultsAmong allo‐HSCT patients, 11 patients developed GVHD, and 6 of them developed aDGVHD. Morphological and functional changes of the colonic mucosa occurred after allo‐HSCT. Indeed, the perimeter of colonic crypts was significantly increased in allo‐HSCT patients compared to controls as well as crypt lumen fluorescein leakage (53% vs. 9%), whereas crypts sphericity, roundness, Feret diameter, and mean vessel area were significantly decreased in allo‐HSCT patients compared to the control group. In addition, interleukin‐6 (IL‐6), IL‐33, and IL‐15 levels in the supernatants of 24 h explant cultures of colonic biopsies were significantly increased in allo‐HSCT patients compared to controls. Finally, there was no difference in pCLE parameters, intestinal permeability, and inflammatory cytokines between patients who developed aDGVHD and those who did not.ConclusionThis pilot study identified early colonic mucosa remodeling after allo‐HSCT conditioning therapy, that is morphological and functional mucosal alterations as well as mucosal inflammation. As to whether these changes are first steps in GVHD initiation and could be considered as predictive biomarkers of aDGVHD need to be determined in a larger cohort of patients.

Different Wood Anatomical and Growth Responses in European Beech (Fagus sylvatica L.) at Three Forest Sites in Slovenia.

European beech (Fagus sylvatica L.) adapts to local growing conditions to enhance its performance. In response to variations in climatic conditions, beech trees adjust leaf phenology, cambial phenology, and wood formation patterns, which result in different tree-ring widths (TRWs) and wood anatomy. Chronologies of tree ring width and vessel features [i.e., mean vessel area (MVA), vessel density (VD), and relative conductive area (RCTA)] were produced for the 1960–2016 period for three sites that differ in climatic regimes and spring leaf phenology (two early- and one late-flushing populations). These data were used to investigate long-term relationships between climatic conditions and anatomical features of four quarters of tree-rings at annual and intra-annual scales. In addition, we investigated how TRW and vessel features adjust in response to extreme weather events (i.e., summer drought). We found significant differences in TRW, VD, and RCTA among the selected sites. Precipitation and maximum temperature before and during the growing season were the most important climatic factors affecting TRW and vessel characteristics. We confirmed differences in climate-growth relationships between the selected sites, late flushing beech population at Idrija showing the least pronounced response to climate. MVA was the only vessel trait that showed no relationship with TRW or other vessel features. The relationship between MVA and climatic factors evaluated at intra-annual scale indicated that vessel area in the first quarter of tree-ring were mainly influenced by climatic conditions in the previous growing season, while vessel area in the second to fourth quarters of tree ring width was mainly influenced by maximum temperature and precipitation in the current growing season. When comparing wet and dry years, beech from all sites showed a similar response, with reduced TRW and changes in intra-annual variation in vessel area. Our findings suggest that changes in temperature and precipitation regimes as predicted by most climate change scenarios will affect tree-ring increments and wood structure in beech, yet the response between sites or populations may differ.

Different response of earlywood vessel features of Fraxinus mandshurica to rapid warming in warm-dry and cold-wet areas

Xylem anatomical features are constantly adapting to changing environmental conditions, and are directly related to the key functions and physiological processes of trees. However, little is known about the responses of xylem to recent rapid warming in many areas. Based on the anatomical features of the xylem of Fraxinus mandshurica Rupr. from 14 sites in two contrasting areas (warm-dry and cold-wet) of northeast China, the plasticity response and adaptation strategies of radial growth, earlywood vessels (EWV), and hydraulic features of F. mandshurica to climate change were studied. Results showed that, compared with the cold-wet area, F. mandshurica in warm-dry area had wider rings, larger vessel area, higher number of vessels (VN), larger hydraulic diameters (Dh) and higher theoretical tree-ring hydraulic conductivity (Kh). On the contrary, the vessel density (VD), percentage of EWV (PC) and xylem-specific theoretical hydraulic conductivity (Ks) in warm-dry area was lower than those in cold-wet area. In these two areas, the RW, mean vessel area (MVA), total vessel area (TVA), VN, Dh, and Kh were significantly positively correlated with temperature, and negatively correlated with winter moisture. However, the PC, VD, and Ks were inversely related to climate factors in the two areas. F. mandshurica can adjust the density and proportion of EWV by changing the configuration of earlywood and latewood to cope with the interannual climate change and balance the hydraulic efficiency and safety. Rapid warming significantly increased the growing season length and hydraulic efficiency of F. mandshurica in warm-dry and cold-wet areas, thus maximizing carbon fixation. This provides a potential physiological explanation for the growth increase and range expansion of the main broadleaf tree species in temperate zone of northeast China in recent years. F. mandshurica in warm-dry areas benefits greatly from continuous climate warming, but the risk of hydraulic failure may increase.

Ring width and vessel features of the mangrove Excoecaria agallocha L. depend on salinity in the Sundarbans, Bangladesh

The Bangladesh Sundarbans is the largest continuous mangrove in the world that providing crucial environmental services, particularly related to coastal protection and livelihoods of millions of people. However, anthropogenic disturbances, diseases infestation and environmental changes including sea level rise (SLR) and fresh-water flux into the delta are threatening the Sundarbans and other mangrove ecosystems worldwide. Protection of mangrove ecosystems requires knowledge on factors that mainly drive growth and vitality of tree species to evaluate which consequences can be expected from, mainly hydrology-related, environmental changes. In this study, we assessed the nature and periodicity of tree rings in Excoecaria agallocha, a wide spread mangrove species in the Bangladesh Sundarbans. We also analysed the influence of climatic factors, such as precipitation, temperature and vapor pressure deficit (VPD), and river discharge, as a proxy of salinity on ring width (RW) and vessel features, such as mean vessel area (MVA) and mean vessel density (MVD). E. agallocha forms distinct tree-ring boundary that characterized by a narrow (2–4 cells wide) band of radially flattened fibres. The RW as well as the MVA and MVD are crossdatable. The RW is mainly driven by salinity which is influenced by freshwater inputs through precipitation during monsoon along with river discharge January to April. The MVA and MVD responded to similar seasons and months as RW, but mostly with opposite signs in MVD. The results suggest that fresh water inputs through precipitation and river discharge positively influence the radial growth of E. agallocha in the Sundarbans. The RW and vessel features can be used as proxies to explore the growth dynamics of this species, especially in relation to global environmental changes.

Adjusting xylem anatomy and growth to inter-annual climate variability in two Fabaceae species (Centrolobium microchaete, Cenostigma pluviosum) from Bolivian dry tropical forests

Climate-growth relationships are strong in seasonally dry tropical forests (SDTFs). To better understand the ecological processes controlling these relationships we need to assess the long-term responses of wood anatomy and radial growth to year-to-year climate variability. We assessed how wood-anatomical traits (mean vessel area –MVA– and vessel density –VD–, percentage of conductive area –CA–, xylem-specific estimated hydraulic conductivity –Ks–) and growth responded to local climate (mean temperature, total precipitation, estimated moisture) variability and teleconnections (Pacific Decadal Oscillation) between 1970 and 2011 in two Fabaceae tree species (Centrolobium microchaete and Cenostigma pluviosum) coexisting in a Bolivian SDTF. We found that C. microchaete produced wider vessels and was more responsive to both local climate conditions and teleconnections than C. pluviosum. In C. microchaete VD positively responded to average temperature in the late-wet season and in the previous dry season, and CA and Ks were higher in years with warmer wet and previous early-dry seasons, as well as in years with higher PDO values. These responses were independent from ring-width variability only for C. microchaete. For C. pluviosum, vessel chronologies were more responsive to local temperature variability, and only MVA and CA positively and negatively responded to moisture in the early-dry and the previous dry seasons, respectively. Our results show that wood hydraulic structure in SDTFs is responsive to climate fluctuations. The combined study of ring width and wood anatomy allows having a more complete picture of the influence of climate on growth, particularly in species as C. microchaete which show low collinearity of tree-ring width and wood plasticity in response to climate variability.