Changes In Pn Research Articles

Can the dietary inorganic nitrate supplementation mitigate the vascular dysfunction in elderly with Alzheimer’s disease?

Aging and Alzheimer disease (AD) are both characterized by progressive reduction in nitric oxide bioavailability and endothelial function impairment. Promising studies on young healthy individuals underly the positive effect of dietary nitrate supplementation on endothelial function. However, the pharmacokinetics of the plasma nitrate and nitrite (PN) and the accompanying endothelial responsiveness following the oral nitrate ingestion in healthy elderly (HE) and patients with AD is not clear. Our hypothesis was that due to the reduction of nitric oxide bioavailability during aging and AD, an equal dose of oral nitrate (ON) would ameliorate the endothelial responsiveness more in the HE and even more in patients with AD in comparison to healthy young subjects (HY). Therefore, with the aim of investigating the pharmacokinetics of PN and the time-course endothelial responsiveness in response to a single dose ON, 10 HY (25±4 YRS), 10 HE (72±8 YRS) and 13 AD (73±7 YRS) were recruited. PN levels and endothelial responsiveness (single-passive leg movement (ΔPLM)) were measured in the recruited individuals prior to (T0) and hourly for 4 hours (T1, T2, T3, and T4) after: a) a single dose of ON; and b) a single dose of placebo. As expected at T0 both PN and ΔPLM were significantly reduced in the HE and even more reduced in the AD in comparison to the HY (all p<0.001). No changes in PN nor ΔPLM were detected in any group following placebo intake. PN increased significantly in all three groups at T1 (p<0.001) and constantly increased up to T4, but no differences were detected between time points T1 to T4 in any group. ΔPLM increased significantly in all three groups at T2, reaching highest values at T4 (p<0.001). However, AD exhibited significantly lower ΔPLM values at any time point compared to HY (p<0.0001) and HE (p<0.001). Significant correlation between PN and ΔPLM was found (p<0.001, R2=0.1654). Contrary to our hypothesis, the results of this study suggest that the PN pharmacokinetics following a single dose of ON is similar in HY, HE and AD. Moreover, the expected time-course amelioration of the endothelial responsiveness was reduced in the HE and even more reduced in the AD, suggesting that other factors, rather than the nitric oxide bioavailability, are playing a role in the age- and AD-related vascular dysfunction. Ricerca di Base 2017 - RBVR17XRSA - Effectiveness of exercise and nitrate supplementation on progression of dementia in patients with Alzheimer’s disease. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Clinicopathological Profile of Ampulla of Vater and Pancreas Malignancies at Cipto Mangunkusumo Hospital in 2015-2019

Background
 Malignancies of ampulla of vater and pancreas are often difficult to distinguish. Malignancies in ampulla of vater include malignancies in major duodenal papilla, distal common bile duct and pancreatic duct opening (Wirsung). The origin of the primary tumor, histopathological diagnosis and staging play a role in therapy and prognosis. WHO Classification of tumors of the digestive system, 2019 made changes in tumor staging following the system of the American Joint Committee on Cancer (AJCC), 8th edition. This study was conducted to determine types of pancreatic and ampullary malignancies, demographic distribution, location, profile, histomorphology and tumor staging changes in the 7th edition of the AJCC to 8th edition of the AJCC in the WHO Classification of tumors of the digestive system, 2019. The aim to determine clinicopathological profile of malignancies of ampulla of vater and pancreas as well as tumor staging changes based on AJCC edition 8.
 Methods
 Observational descriptive study on pancreatic and ampulla vater malignancy resection preparations at Department of Anatomic Pathology FKUI/RSCM, period January 2015 to December 2019 that met the inclusion criteria. Demographic evaluation, tumor location, histopathological profile and patient staging changes were carried out based on the 8th edition of AJCC.
 Results
 There were 27 cases of adenocarcinoma in ampulla of vater, 10 cases of pancreatic ductal adenocarcinoma, 1 case of mucinous cystic neoplasm with adenocarcinoma focus, 1 case of serous cystadenocarcinoma, 7 cases of PanNET, 2 cases of PanNEC, 3 cases of SPN, 1 case of MiNEN. Changes in pT were present in 29 cases. Changes in pN were present in 6 cases.
 Conclusion
 The diagnosis and pathological staging are in accordance with the 2019 WHO digestive system tumor classification. Tumor differentiation, presence or absence of lymphovascular invasion, perineural invasion and lymph node metastases and incision margin status are important histopathological parameters.

The morphology and nutrient content drive the leaf carbon capture and economic trait variations in subtropical bamboo forest.

Carbon absorption capability and morphological traits are crucial for plant leaf function performance. Here, we investigated the five bamboos at different elevations in Wuyi Mountain to clarify how the leaf trait responds to the elevational gradient and drives the photosynthetic capacity variations. The Standardized Major Axis Regression (SMA) analyses and the Structural Equation Model (SEM) are applied to identify how the bamboo leaf trait, including the ratio of leaf width to length (W/L), leaf mass per area (LMA), photosynthesis rates (Pn), leaf nitrogen, and phosphorus concentration (Leaf N and Leaf P) response to elevation environment, and the driving mechanism of Pn changes. Across the five bamboo species, our results revealed that leaf P scaled isometrically with respect to W/L, leaf N scaled allometrically as the 0.80-power of leaf P, and leaf N and leaf P scaled allometrically to Pn, with the exponents of 0.58 and 0.73, respectively. Besides, the SEM result showed altitude, morphological trait (W/L and LMA), and chemical trait (leaf N and leaf P) could together explain the 44% variations of Pn, with a standard total effect value of 70.0%, 38.5%, 23.6% to leaf P, leaf N, and W/L, respectively. The five bamboo species along the different elevational share an isometric scaling relationship between their leaf P and W/L, providing partial support for the general rule and operating between morphological and chemical traits. More importantly, the leaf W/L and leaf P as the main trait that affects leaf area and P utilization in growth and thus drives bamboo leaf photosynthetic capacity variations in different elevations.

Photosynthesis, Respiration, and Thermal Energy Dissipation in Leaves of Two Phenotypes of Plantago media L. under Environmental Conditions

The ability to maintain the balance between the absorbed light energy and energy used in photosynthesis is a key factor of plant adaptation to variable environmental conditions. In this work, diurnal variations in photosynthesis, respiration, thermal energy dissipation, and the activity of the antioxidant system were studied in hoary plantain (Plantago media L.) growing on an open slope (sun plants) and under natural shading in the herbage (shade plants). The highest leaves net photosynthetic rate (Pn) was observed early in the morning and amounted to 2.6 and 9.2 μmol CO2/m2 s in shade and sun plants, respectively. In the daytime, the Pn values of sun plants decreased significantly (threefold) along with the decrease in stomatal conductance; changes of both parameters developed concurrently with the increase in insolation and air temperature. The Pn changes in leaves of shade plants were less pronounced and weakly dependent on stomatal conductance. The leaves of shade plants contained comparatively high amounts of soluble carbohydrates, whereas the sun plant leaves accumulated larger amounts of starch. In the daytime, nonphotochemical quenching (NPQ) of chlorophyll a fluorescence in photosystem II of sun plant leaves could be as large as 2.6 rel. units, which was four- to fivefold higher than NPQ in shade plants. In leaves of sun plants in the morning and evening hours, the ratio of cytochrome pathway (CP) and the alternative (AP) respiratory pathways was approximately 1.0, whereas this ratio decreased to 0.4 during the day, synchronously with an increase in NPQ. The CP/AP ratio in shade plant leaves remained constant throughout the diurnal cycle and equaled 1.4, indicating a comparatively high energy efficiency of respiration in shaded plants growing under the grass canopy. The leaves of sun plants featured an increased content of superoxide anion radical and hydrogen peroxide as well as the elevated activity of antioxidant enzymes (superoxide dismutase, guaiacol peroxidase) that control the accumulation of reactive oxygen species. The results emphasize the importance of coordinated changes in energy-dissipating processes and the activity of the antioxidant system for maintaining the energy and redox balance in phototrophic tissues during long-term adaptation of plants to environmental conditions, excessive insolation in particular.

Abstract PO-043: Plexiform neurofibroma microenvironment at single-cell resolution

Abstract Plexiform neurofibromas (PN) are benign nerve sheath Schwann cell tumors, which occur in at least 50% of individuals with loss of function mutations in the NF1 tumor suppressor gene, an off signal for RAS-GTPases. Tumors form, at least in part, through activation of the RAS-MAPK pathway in Schwann cells. Though benign, PN can cause significant morbidity and are often inoperable due to integration with vital peripheral nerves. Recent clinical trials have shown that MEK inhibition can shrink most PN, but continued MEK inhibition is required for sustained response. It is recognized that PN contain many cell types in addition to Schwann cells, and that Schwann cells are present in varying proportions. However, biomarkers for many cell types have not yet been identified, and it is not known whether subpopulations of certain cell types exist within neurofibromas. To address these issues, we performed single cell RNA sequencing on PN using a genetically engineered mouse model which closely recapitulates human PN. We have characterized tumor composition, and identified PN Schwann cells, satellite glial cells, endothelial cells, fibroblasts, macrophages, T cells, dendritic cells, and other previously unreported cell types. We identified multiple subpopulations of Schwann cells, macrophages and fibroblasts within benign PN. Cluster by cluster comparison of PN to age-matched healthy nerve and to pretumor nerve tissue from the same mouse model revealed gene regulatory networks that are significantly altered in PN, after loss of NF1 function. Further, inference of cell-cell communication networks shows robust changes in PN that are absent before tumors form, and that are potentially targetable. Comparison to MEK inhibitor treated PN and to human PN sc-RNASeq is ongoing. Taken together, these approaches characterize PN, provide potential biomarkers for cell populations and identify targets for drug treatment. Supported by NIH (NINDS-28840) and the DOD Program on Neurofibromatosis. LK is supported by NIH Ruth L. Kirschstein T32. Citation Format: Leah J. Kershner, Jianqiang Wu, Nathan Salomonis, Nancy Ratner. Plexiform neurofibroma microenvironment at single-cell resolution [abstract]. In: Proceedings of the AACR Virtual Special Conference on Tumor Heterogeneity: From Single Cells to Clinical Impact; 2020 Sep 17-18. Philadelphia (PA): AACR; Cancer Res 2020;80(21 Suppl):Abstract nr PO-043.

Water stress altered photosynthesis‐vegetation index relationships for winter wheat

AbstractThe photosynthetic rate (Pn) of winter wheat (Triticum aestivum L.) is directly affected by water conditions, which can be effectively estimated by coupling vegetation indices (VIs). Establishing sound empirical models between VIs and Pn of winter wheat under different water conditions therefore is a sound approach for predicting Pn for broad applications. A rainout‐shelter field experiment was conducted to investigate the changes in Pn and VIs (normalized difference vegetation index [NDVI], enhanced vegetation index [EVI], ratio vegetation index [RVI], photochemical reflectance index [PRI]) under five water stress conditions. We found that: (a) heavy and moderate drought stress inhibited Pn, with their accumulated effects became more significant with the duration of treatments while the light drought stress and slight water logging produced minor effects on Pn. Heavy and moderate drought stress also caused the peak time of Pn preceded during the growth period; (b) NDVI showed low sensitivity to vegetation coverage while EVI explained more seasonal variation than other VIs when leaf area index (LAI) was >3; (c) the linear models between Pn and EVI under heavy () and moderate () water stress were selected as the best model for Pn, while a power function for Pn‐NDVI performed better under sufficient water supply (Pn = 37.982NDVI3.0101) and slight water logging (Pn = 28.024NDVI2.5646). Our results demonstrated that Pn–VI relationships varied by water stress for a winter wheat over the growing season. These results could be used for the prediction of winter wheat Pn under water stress at a large spatial scale.

Seasonal variation of fig tree (Ficus carica L.) physiological characteristics reveals its adaptation performance

In the context of climate change, understanding fig trees physiology is very important, since the areas of fig production registered a large climate variability that severely affects fruit quality. The present study was conducted to evaluate the seasonal changes of physiological leaf behaviour of two Tunisian fig cultivars, Zidi and Bither Abiadh during two years. Plants were subjected to full irrigation to maintain the soil moisture around pot capacity through the experimental period. Leaf gas exchange characteristics (net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E)), chlorophyll content index, leaf temperature and the maximum photochemical efficiency of PSII (Fv/Fm) were measured. Results showed that the photosynthetic characteristics changed during the growing season. Changes of photosynthetic CO2 assimilation, stomatal conductance, and chlorophyll content were not significantly affected by cultivar, and their variation was attributed to year. Seasonal changes of PN and gs were similar suggesting that both processes are dependent. Indeed the best photosynthetic performance of fig occurred about 80-87 days after bud break (spring) of the second season of growth, being supported by a high stomatal aperture. The lowest values of PN, E and gs were recorded 156 days after bud break (summer) for 2017. The decrease of gas exchange rates and high temperatures were registered during the same dates. A little increase of the photosynthetic characteristics and chlorophyll content was noticed in the autumn period, about 180 days after bud break, until a definitive decrease at the end of the growing season with the occurrence of low winter temperature. These results revealed particular adaptive behaviour and could be used as preliminary criteria to predict the future impact of environmental abiotic stresses on ecophysiological fig tree behaviour.

Constraints on crust-mantle transition zone with Pn waveforms: A case study of eastern China and southern Korean Peninsula

The seismic velocity structure of the crust-mantle transition zone (CMTZ) provides key constraints on crustal dynamics, and can be studied with Pn wave which propagates horizontally along the Moho discontinuity. In this study, we first explore an effect of velocity-gradient structures in the CMTZ through synthetic Pn waveforms, and demonstrate that the shape of Pn changes from step-like to pulse-like when the CMTZ becomes from sharp to a gradient velocity structure, respectively. We then use Pn waveforms of the regional earthquakes (the July 2012 Mw 4.8 earthquake in east China and the September 2016 Mw 5.1 earthquake in South Korea) to examine the CMTZ structures to the west and east of the Yellow Sea and thus to constrain tectonic affinity between the eastern China and southern Korean Peninsula. The Pn waveforms from the Mw 4.8 event in east China show that the Moho in southern Yangtze Craton is sharp whereas there may be a gradient structure in CMTZ with a 6–10 km thickness in northern Yangtze Craton. The Pn waveforms from the Mw 5.1 event in South Korea show that the CMTZ in South Korea is also sharp, similar to the southern Yangtze Craton. Observed difference in CMTZ structures suggest that Sulu Orogenic Belt may extend along the north of the Gyeonggi Massif in Korea.

遮光对香果树幼苗光合特性及叶片解剖结构的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 遮光对香果树幼苗光合特性及叶片解剖结构的影响 DOI: 10.5846/stxb201810312347 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 江苏省重点研发计划（现代农业）项目（BE2017387） Effects of shading on photosynthetic characteristics and leaf anatomical structure of Emmenopterys henryi seedlings 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:设置了全光照（L0）、透光率60%（L1）、透光率25%（L2）、透光率10%（L3）4种光环境，研究了不同遮光处理对香果树幼苗光合作用及叶片解剖结构的影响。结果表明：（1）遮光对香果树幼苗净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、气孔限制值（Ls）、胞间CO2浓度（Ci）、蒸汽压亏缺（Vpdl）均产生了显著影响。全光和L1处理下Pn和Tr日变化呈明显的双峰曲线，中午出现了明显的"午休"，其余处理的变化相对缓和，双峰和"午休"现象不明显；Gs的日变化规律与Pn基本一致；Ci的日变化整体呈先期缓慢降低后期抬升的趋势，与对照相比遮光显著提高了叶片胞间CO2浓度；Ls和Vpdl呈现出先升后降的弧形变化，并且遮光下Ls和Vpdl日均值显著低于全光照。一天中Pn和Tr的日均值大小排序为L1 > L0 > L2 > L3。（2）不同光环境下香果树幼苗的光合响应特征明显不同。全光下，香果树幼苗能够维持较高的净光合作用速率而未呈现明显的光抑制，表现出一定的光忍耐和喜光性。L1处理下的最大净光合速率（Pmax）、暗呼吸速率（Rd）和表观量子效率（AQY）显著增加，说明香果树对光强具有一定的可塑性，轻度遮光有利于光合效率提高；强度遮光（L2、L3）导致光补偿点（LCP）和光饱和点（LSP）显著降低，有利于充分利用弱光，但Pmax、Rd明显下降，光合效率受到抑制。（3）遮光显著影响了香果树叶片的气孔分布。遮光条件下香果树叶片的气孔密度显著减小，气孔器长度、宽度与单个气孔器面积也呈现类似的变化。（4）遮光条件下香果树叶片厚度减小，上表皮增厚，下表皮变薄。栅栏组织厚度（PT）变薄，海绵组织（ST）不发达，PT/ST增加；维管束内单列导管数目和导管直径均有明显增大，促进了叶片水分传导运输。（5）在育苗生产中，为了适应香果树幼苗生长发育的需求，建议有效辐射强度保持在自然光强的60%以上。 Abstract:Effects of shading on photosynthesis characteristics and leaf anatomical structure of Emmenopterys henryi seedlings were studied using four shading treatments including full sunlight (L0), 60% sunlight (L1), 25% sunlight (L2), and 15% sunlight (L3), respectively. The results showed that:(1) Shading had an significant effect on the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), stomatal limitation value (Ls), intercellular CO2 concentration (Ci), and vapor pressure deficit (Vpdl) of E. henryi seedlings. The diurnal changes of Pn and Tr under L0 and L1 treatments showed obviously bimodal curves, and the "noon break" appeared at 12:00. Their changes under L2 and L3 treatments were relatively mild, and the "noon break" were not obvious. The variation of Gs was basically consistent with that of Pn. The variation of Ci showed a tendency of declining slowly at early stage and rising rapidly later. Compared with the control, the shading promoted significantly increase of the Ci. Both Ls and Vpdl showed the arc changes of slow rising in advance and decreasing in the latter stage, and the daily averages under shading were lower significantly than the control. The order of daily averages of Pn and Tr was L1 > L0 > L2 > L3. (2) The photosynthesis-light response characteristics of E. henryi seedlings under four light regimes were obviously different. The seedlings grown under the full sunlight condition could maintain a higher Pn without obvious photoinhibition, showing a certain degree of shading-tolerance and light-demanding. The maximum net photosynthetic rate (Pmax), dark respiration rate (Rd), and apparent quantum efficiency (AQY) under L1 treatment increased more significantly than the control. Therefore, the E. henryi seedlings had some plasticity to light intensity. The mild shading was beneficial to the improvement of photosynthetic efficiency. Serious shading (L2 and L3) resulted in a significant decrease of light compensation point (LCP) and light saturation point (LSP), which was beneficial to make full use of weak light. But they resulted in Pmax and Rd decrease obvious, which inhibited photosynthetic efficiency. (3) The shading significantly affected the stomatal distribution on leaves surface of E. henryi seedlings. Under shading condition, the stomata density decreased significantly, and the stomata length, the stomata width, and single stomatal area was similar. (4) Under shading, the leaf thickness decreased, the upper epidermis thickened, and the lower epidermis thinned. The thickness of palisade tissue (PT) decreased and sponge tissue (ST) was not fully developed, and the value of PT/ST increased. Moreover, the number of vessel in vascular bundle and the vessel diameter increased significantly, which promoted the transport of water in leaves. (5) In order to meet the needs of growth and development of E. henryi seedlings in cultivation, we suggested that the effective radiation intensity should be above 60% of natural light intensity. 参考文献 相似文献 引证文献

Physiology of strawberry plants under controlled environment: diurnal change in leaf net photosynthetic rate

Effect of light intensity and plant sink/source balance on strawberry plant photosynthesis was investigated in this study. Previous research (Inaba, 2007) showed diurnal decline of photosynthetic capacity in strawberry, indicating potential presence of negative photosynthesis feedback. We conducted monthly measurements of leaf net photosynthetic rate (Pn), stomatal conductance, intercellular CO2 concentration (Ci) and transpiration rate in strawberry cultivars 'Albion' and 'Nyoho' in greenhouse, during winter/spring production season. Measurements were taken hourly from 9 am to 4 pm using portable leaf photosynthesis measurement system under 1000 µmol m-2 s-1 photosynthetic photon flux (PPF) and 400 µmol mol‐1 CO2. Pn measurements were conducted for 'Speedella' tomato for comparison. Sink load of flowers and fruits was estimated from number of flowers and fruits at the measurement day and the fruit yield from the consecutive 4 weeks. Potential source strength was evaluated based on number of leaves and the daily light integral (DLI, 400-700 nm). We observed seasonal changes in maximum Pn, as well as diurnal change in Pn in both strawberry cultivars. As expected, in tomato, Pn was relatively constant regardless of time of day or month. Analysis showed significant positive correlation between estimated ratios of sink/source and slopes of linear equations applied for diurnal change in Pn. Also, Pn was negatively correlated with Ci but not significantly correlated with vapor pressure deficit in greenhouse, suggesting diurnal decline in Pn was likely due to negative feedback of photosynthesis and not to water stress. Results indicate morning hours as critical time for promoting photosynthesis in strawberry, when negative feedback of photosynthesis is occurring. Understanding diurnal change of plant photosynthetic capacity could lead to develop practices in strawberry production under controlled environment in order to maximize production.

Photosynthetic responses of a wheat (Asakaze)-barley (Manas) 7H addition line to salt stress

The photosynthetic responses to salt stress were examined in a wheat (Triticum aestivum L. cv. Asakaze)–barley (Hordeum vulgare L. cv. Manas) 7H addition line having elevated salt tolerance and compared to the parental wheat genotype. For this purpose, increasing NaCl concentrations up to 300 mM were applied and followed by a 7-day recovery period. Up to moderate salt stress (200 mM NaCl), forcible stomatal closure, parallel with a reduction in the net assimilation rate (P N), was only observed in wheat, but not in the 7H addition line or barley. Since the photosynthetic electron transport processes of wheat were not affected by NaCl, the impairment in P N could largely be accounted for the salt-induced decline in stomatal conductance (g s), accompanied by depressed intercellular CO2 concentration and carboxylation efficiency. Both, P N and nonstomatal limitation factors (Lns) were practically unaffected by moderate salt stress in barley and in the 7H addition line due to the sustained g s, which might be an efficient strategy to maintain the efficient photosynthetic activity and biomass production. At 300 mM NaCl, both P N and g s decreased significantly in all the genotypes, but the changes in P N and Lns in the 7H addition line were more favourable similar to those in wheat. The downregulation of photosynthetic electron transport processes around PSII, accompanied by increases in the quantum yield of regulated energy dissipation and of the donor side limitation of PSI without damage to PSII, was observed in the addition line and barley during severe stress. Incomplete recovery of P N was observed in the 7H addition line as a result of declined PSII activity probably caused by enhanced cyclic electron flow around PSI. These results suggest that the better photosynthetic tolerance to moderate salt stress of barley can be manifested in the 7H addition line which may be a suitable candidate for improving salt tolerance of wheat.

Relations Between Mn Concentration and Yield, Nutrient, Water Status, and Gas Exchange Parameters of Tomato

Abstract Nutrition is one of the most important factors influencing quantitative and qualitative plant yield. This study examined the effect of manganese (Mn) in nutrient solution on photosynthetic activity parameters, and the relations between photosynthetic activity parameters, yield and plant nutrient status in tomato (Solanum lycoper-sicum L.). Mn supplementation significantly modified the nutrient content of leaves. Macronutrient content var-ied less than micronutrient content. The optimal Mn concentration differed between the studied cultivars. Both Mn deficit and Mn excess caused a decrease of tomato yield. Gas exchange parameters, relative water content (RWC) and specific leaf area (SLA) were measured in fully expanded tomato leaves. Certain levels of Mn were found to be needed for proper plant function and future yield, and toxic effects of excess Mn were noted. Changes in PN (net photosynthetic rate) were found to be the first signal of plant response to higher Mn supply, while yield was as for optimal Mn concentrations. Under Mn treatment, uptake of some nutrients increased. A higher level of absorbed Mg led to a higher photosynthesis rate and increased stomatal opening. PN and gs (stomatal con-ductance) also increased, while Ci (intercellular CO2 concentration) decreased, indicating proper CO2 consumption during the assimilation process.

First in Human High-Resolution Imaging of Regional Lung Function by Single Energy Xenon CT Compared to Ventilation SPECT

underwent SABR in our department. The radius of the smallest PN was 0.3 cm while the biggest one was 2.1 cm. An intensity based deformable image registration (DIR) workflow with manual modification has been developed and applied on extreme tidal volumes to determine the deformation map between inhale and exhale images. Next, an elasticity parameter was derived by calculating the ratio of the volume changes of PN to that of a 1 cm ring of lung tissue surrounding the PN. The proposed formulation of elasticity enables us to compare volume changes of two different PN in two different locations of lung. Secondly, the PN were manually delineated on the inhale and exhale images by two different observers and the volume changes of the PN were compared to those calculated by DIR. Results: Dice similarity coefficient between the delineated tumor by observer 1 versus observer 2 is 0.81 0.1, whereas the dice value is 0.79 0.07 and 0.79 0.06 between DIR and observer 1 and DIR and observer 2, respectively. Calculated volume ratio for PN is 0.91 0.18 compared to the volume changes of 1 cm of regional lung tissue 0.75 0.13, which clearly shows that volume change of PN is less than that of the surrounding lung (p<0.0001). Conclusions: We developed a non-invasive method to determine the elasticity of PN based on deformable image registration of breath-hold images. The tool was validated against manual contouring. Preliminarily, PN elastometry distinguishes proven malignant PN from the surrounding lung, suggesting its potential utility as a non-invasive diagnostic tool. Author Disclosure: M. Negahdar: None. D.B. Shultz: None. R.V. Eyben: None. C. Fasola: None. A.S. Yu: None. L. Tian: None. D. Fleischmann: None. L. Gable: None. X. Shan: None. M. Diehn: None. B.W. Loo: None. P.G. Maxim: None.

Fast Spatiotemporal Correlation Spectroscopy to Determine Protein Lateral Diffusion Laws in Live Cell Membranes

Fast Spatiotemporal Correlation Spectroscopy to Determine Protein Lateral Diffusion Laws in Live Cell Membranes

吉林不同生境防风夏季光合特性

PDF HTML阅读 XML下载 导出引用 引用提醒 吉林不同生境防风夏季光合特性 DOI: 10.5846/stxb201208081122 作者: 作者单位: 吉林农业大学,中国科学院东北地理与农业生态研究所,吉林农业大学,吉林农业大学,吉林省和龙市科学技术情报研究所,吉林农业大学 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（31300270）；国家科技支撑计划项目（2011BAI03B01-02）；教育部博士点新教师基金（20112223120004）；吉林省科技发展计划项目（20130522048JH） Photosynthetic characteristics of Saposhnikovia divaricata in different habitats in summer Author: Affiliation: College of Chinese Medicinal Materials,Jilin Agricultural University,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,College of Chinese Medicinal Materials,Jilin Agricultural University,College of Chinese Medicinal Materials,Jilin Agricultural University,Helong Institute of Scientific and Technical Information of Jilin Province,College of Chinese Medicinal Materials,Jilin Agricultural University 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:采用LCpro+全自动便携式光合仪同时测定了长春、长岭和白城3个生境防风的光合作用及环境因子，研究不同生境防风净光合速率、蒸腾速率及水分利用效率等日变化特征及其与生态因子之间关系，并采用通径分析法分析各环境因子对防风净光合速率的直接和间接影响，探讨防风的光合生理规律，为进一步研究防风的光合生理提供依据。结果表明，各环境因子之间存在相互作用，在影响防风光合作用的环境因子中，光合有效辐射（PAR）是驱动因子，它的变化驱动了大气温度（Ta）、叶片温度（Tl）变化，Ta升高引起空气密度的变化是午间相对湿度（RH）和大气浓度CO2（Ca）降低的一个重要原因。环境因子中对Pn直接作用由大到小长春为Tl >Ta > PAR >Ca >RH ，长岭为PAR >Tl > RH > Ca >Ta，白城为Ta >Tl >RH > PAR >Ca。长春、长岭PAR与Pn相关系数最大，而白城地区Ca与Pn相关系数最大，说明防风叶片对不同环境因子的反应有所不同。8月份3个地区防风净光合速率日变化均呈双峰型曲线，具有明显的光合"午休"现象。长春、长岭地区防风光合"午休"现象主要由气孔因素引起，白城地区防风光合"午休"现象主要由非气孔因素引起的。3个生境防风的Pn与Gs之间均呈显著的正相关关系，白城的Gs比长春、长岭地区的低44%左右，这是防风为适应高温干旱的环境而形成的生理反应。不同生境土壤含水量间差异显著，白城地区土壤水分含量很低，只有20.35%，仅是长春土壤含水量的56.50%，而空气温度较高，强辐射使气孔叶片蒸腾失水加剧，导致叶片含水量也很低，仅仅为56.60%，高温干旱使防风叶温升高，防风磷酸化、电子传递、酶活性等受到抑制，导致光合速率降低。因此，白城地区长期高温胁迫是限制防风Pn的主要原因。 Abstract:Photosynthesis of Saposhnikovia divaricata (Turcz.) Schischk. and environmental factors were measured by using LCPro+ portable photosynthesis system in Changchun, Changling and Baicheng, the diurnal changes in net photosynthetic rate (Pn), transpiration rate (E) and water use efficiency (WUE) of S. divaricata and their relationships with environmental factors were studied, and direct and indirect effects of environmental factors on net photosynthetic rate were calculated through the path analysis in different habitats in order to discuss photosynthetic physiology rule of S. divaricata . This knowledge could provide basis for further study the photosynthetic physiology of S. divaricata . The results showed that there were significant interactions among environmental factors, variation of photosynthetically active radiation (PAR) triggered the fluctuations of air temperature (Ta) and leaf temperature (TL), and Ta was closely related to the air density, which had significant impacts on the air CO2 concentration (Ca) and relative humidity (RH), the reduce of air density affected by increase of Ta was the one of important causes, which decreased the RH and Ca at noon. Environmental factors driven intrinsically by PAR superposed an integrative effect on Pn. And the responses of the species to the environmental factors were different in different habitats, and the direct effects of environmental factors in three different habitats were of the order: Tl >Ta > PAR >Ca >RH in Changchun, PAR >Tl >RH >Ca >Ta in Changling and Ta >Tl >RH > PAR >Ca in Baicheng. The correlation coefficients between PAR and Pn were the biggest in Changchun and Changling, but Ca and Pn was the biggest in Baicheng. The diurnal changes in Pn of the species in different habitats were similar and could be expressed as two-hump curves, reflecting a significant middy depression at noon. The decrease in Pn during midday was mainly resulted from stomatal limitation in Changchun and Changling, but non-stomatal limitation occurred in Baicheng. There were significant positive correlations between Pn and Gs in three ecological regions, Gs in Baicheng was about 44% lower than in Changchun and Changling, this was a physiological reaction in order to response to high temperature and drought in Baicheng. The soil water content differed significantly in different habitats, it was only 20.35% in Baicheng, and that was 56.50% of that in Changchun, but air temperature in Baicheng was high, leaf water content was only 56.60%, which resulted from leaf strong transpiration and water loss affected by intense radiation. So the net photosynthetic rate decreased because of that the phosphorylation, electron transfer and enzyme activities of S. divaricata were restrained by high leaf temperature. So heat-stress was one of critical factors constraining Pn in Baicheng. 参考文献 相似文献 引证文献

Changes in Leaf Spectral Reflectance and Photosynthetic Characteristics with Tree Height in Three Tree Species

As tree grows high,leaves in the top are always affected by water transport resistance,which leads to water deficiency.Accordingly,the biological characteristics of leaves also change.In this paper,3 tree species(Quercus mongolica,Tilia amurensis,and Pinus koraiensis) were observed to study the relationship between leaf spectral reflectance(spectral reflectance R,photochemical reflectance index PRI) and photosynthetic characteristics(photosynthetic rate Pn,transpiration ratio Tr and stomata conductance Cond) with different tree height.The results showed that PRI and photosynthesis in Q.mongolica and T.amurensis had a trend of increasing at the first and decreasing later with tree height.Their variations were significant at different heights(P0.05).In contrast,these indexes of P.koraiensis showed constant increase with tree height.The results indicated that water deficit affected more intensely the leaf photosynthesis in the top of the first 2 tree species than P.koraiensis,probably because of different stomatal regulation mechanism.Additionally,there was a significantly positive relationship between leaf PRI and Pn in Q.mongolica and T.amurensis(r2=0.986,0.890).However,PRI could not reveal the changes of Pn in P.koraiensis,which suggested that PRI should be used in combination with species difference.

Changes in photosynthesis, chlorophyll fluorescence, and antioxidant enzymes of mulberry (Morus ssp.) in response to salinity and high-temperature stress

Photosynthesis, chlorophyll (Chl) fluorescence, and antioxidant enzymes were measured in the mulberry (Morus spp.) cultivars Da 10, Hongguo 2, Anza 1, and Taiwan 72C002, which were subjected to salinity and high-temperature stress (STS; 0.1%, 0.3%, and 0.5% NaCl concentrations, 34.5°C–40.5°C/27.8°C–29.2°C day/night temperatures). Control plants were watered with 1 L of full-strength Hoagland’s nutrient solution with no added NaCl. Net photosynthetic rate (P N), stomatal conductance (g s), and effective quantum yield of photosystem II photochemistry (ΦPSII) increased in Anza 1 and Taiwan 72C002 under 0.1% STS but decreased in Da 10 and Hongguo 2 compared with the control. However, all the above parameters, including Chl content, maximum quantum yield of photosystem II photochemistry (Fv/Fm), nonphotochemical quenching (NPQ), and maximum carboxylation velocity of Rubisco (V cmax, decreased in Taiwan 72C002, Honggua 2, and Da 10 under 0.3% and 0.5% STS, suggesting that photoinhibition occurred under severe STS. Under STS, there were no significant changes in P N, Fv/Fm, ΦPSII, ascorbate peroxidase (APX) activity, superoxide dismutase (SOD) activity, catalase activity, superoxide anion radical (O 2 − ) content, malondialdehyde (MDA) content, soluble sugar content (SSC), and leaf biomass in Anza 1 even at 0.5% STS, showing that Anza 1 displays high resistance to STS. In addition, peroxidase activity was significantly higher in Anza 1 than in the other mulberry cultivars. Significant adverse effects of severe salinity on photosynthesis and Chl fluorescence parameters were observed in Da 10. Additionally, SOD, peroxidase, and APX activities were lower in Da 10, whereas O 2 − and MDA contents were higher in comparison with the other mulberry cultivars under 0.3% and 0.5% STS, suggesting that Da 10 had low resistance to STS. These results show that 0.1% STS had a positive effect on photosynthesis and Chl fluorescence parameters in Anza 1 and Taiwan 72C002, and higher peroxidase activity can to a certain extent explain the higher STS tolerance in Anza 1. Damages to DSM photosystems might be related to lower SOD, POD, and APX activities, which resulted in the accumulation of reactive oxygen species.

香梨两种树形净光合速率特征及影响因素

The objective of this study was to investigate the diurnal variation curves of the net photosynthetic rate( Pn) and relationship between diurnal changes of Pn and the impact factors in open center shape and delayed-open central leader system in Korla fragrant pear. Diurnal changes of Pn and effect of environmental factors( i,e. photosynthetic available radiation,temperature and relative humidity) and physiology factors( i,e. stomatal conductance,transpiration rate and intercellular CO2concentration) on Pn in leaves of Korla fragrant pear were measured using LI-6400 portable photosynthesis system. The relationship between Pn and environmental factors were analyzed by regression analysis and correlative analysis. In order to investigate the effects of tree shape on net photosynthetic rate,we analyzed the relationship between chlorophyll content,specific leaf weight,other photosynthetic parameters and Pn between delayed-open central leader system and open center shape in this study. The results showed that the Pn under two different tree shapes indicated a bimodal curve of the asymmetry,and the midday depression of photosynthesis phenomenon appeared at 14: 00. During the full fruit period,the delayed-open central leader system tree had obviously higher net photosynthetic rate than the open center shape tree in each stage. This phenomenon maight be double impacted by stomatal and non-stomatal factors.Diurnally,photosynthesis increased gradually with increasing light intensity and then decreased at noon. The peak of delayed-open central leader system tree leaves occurred at 11: 00 and 15: 30. The peak of open center shape tree leaves occurred at 11: 00 and 17: 00. The seasonal variation on Pn indicated the Pn is least in June in two shapes of Korla fragrant pear. The Pn increased with leaf chlorophyll( chl) content and specific leaf weight( SLW) increasing. There are positive relations,the correlation index of leaf chlorophyll( chl) content and Pn were 0. 9438 and 0. 8952 in two shapes of Korla fragrant pear. The photosynthetic pigment index of different kinds of tree shapes also had great differences. There were significant correlations between Pn and SLW in delayed-open central leader system and open center shape,but the later is higher than the former. Stomatal conductance( Gs),transpiration rate( Tr) and relative humidity( RH) increased in response to increasing Pn in all the treatments. Sample CO2concentration( Cs) and intercellular CO2concentration( Ci)decreased in response to decreasing Pn in all the treatments. Besides,the Cs,stomatal conductance( Gs),Tr,and Pn have reached highly significant at P ≤0. 01 in delayed-open central leader system. There were significant at P ≤0. 05between Ci,air tempreture( Ta),photosynthetically active radiation( PAR),RH and Pn in delayed-open central leader system. However,the relativity of photosynthetic parameters and Pn were unconspicuous in the open center shape tree,The findings demonstrate that delayed-open central leader system tree had obviously higher sensitivity to the influence factors of net photosynthetic rate than the open center shape tree in this study.

The Effects of Drought Stress on the Photosynthetic Parameters and Dry Leaf Yield of &lt;i&gt;Stevia rebaudina&lt;/i&gt; Bertoni

The effects of drought stress on the photosynthesis and dry leaf yield in the different Stevia rebaudina Bertoni germplasms of: IS-1, QF-1, QTZ4, JD-1 and AL-4 was studied with the pot method in greenhouse. The results indicated that the net photosynthetic (Pn), transpiration rate (Tr) and dry leaf production of stevia showed different degree changes with the continuing of drought-stress time. There was no significant change in Pn, Tr and dry leaf production in short-term drought-stress treatment(Ta:5d), but as the time of drought-stress continuing, the Pn were on the declining trend: the Pn of various materials in T2 (without irrigation for 10d) showed maximum decrease, they decreased for 28.85%, 47.04%, 43.03%, 43.61% and 42.25% than that in T1 (without irrigation for 5d), respectively. The variation trend of Tr in various materials were the same to the Pn. And it indicated that there was no appreciable impact on the dry leaf yield in the mild drought (without water for 5d), but with the drought stress continuing, the dry leaf yield of per plant became less and less. The varying degrees decreases of dry leaf yield in different materials with the same drought stress showed that different materials with different tolerance to drought stress.

五种高速公路边坡绿化植物的生理特性及抗旱性综合评价

A test of potting methods used to control soil water was applied to study the physiological characteristics and drought resistance of five plants used for highway shoulder greening and ecological restoration in northern China.Leaf water potential,photosynthesis parameters and fluorescence parameters of five plants were measured under four levels of water stress.The drought resistance of the plants was evaluated to study the average rate of change in various parameters. The results show:(1) as water stress increased,leaf water potential(ΨL),net photosynthesis(Pn),transpiration(Tr),and stomatal conductance(GS) of the five plants gradually decreased;as water stress increased,water use efficiency(WUE) of the five plants first increased and then decreased but the internal CO2(Ci) of the five plants first decreased and then increased.There were some differences in the changing amplitudes and inflection points of the physiological indices.Sedum spectabile and Iris lactea var.chinensis had relatively small average rates of change,while Opisthopappus taihangensis and Saponaria officinalis had relatively large average rates of change.(2) The Ci of S.spectabile and I.lactea var.chinensis reached a minimum value under moderate water stress(W2),while the Ci of Parthenocissus quinquefolia,O.taihangensis and S.officinalis reached a minimum value under mild water stress(W1).Changes in Gs and Ci under water stress were reflected in changes in Pn;the decrease in Pn observed in S.spectabile and I.lactea var.chinensis were mainly caused by stomatal limitation resulting from the change from a normal water supply(CK) to moderate water stress(W2),while non-stomatal factors caused the changes observed under severe water stress(W3).The decrease in Pn in P.quinquefolia,O.taihangensis and S.officinalis was mainly caused by stomatal limitation under normal water supply conditions(CK) and mild water stress(W1),and by non-stomatal factors under moderate water stress(W2) and severe water stress(W3).WUE of S.spectabile and I.lactea var.chinensis had the highest under moderate water stress.WUE of P.quinquefolia,O.taihangensis and S.officinalis had the highest under mild water stress.(3) As water stress increased,initial inflorescence(Fv),maximum inflorescence(Fm),the ratio of variable to maximum(Fv/Fm),or initial inflorescence(Fv/Fo) of the five plants decreased gradually and Fo of the five plants increased gradually.This indicated the energy of PSII was transformed into a reduction in photochemical energy and additional energy was lost as heat and through fluorescence,which led to reduced photosynthesis.(4) The drought resistance of the five plants was evaluated by principal component analysis based on the average rate of change of each plant under water stress.The comprehensive drought evaluation indices of S.spectabile and S.officinalis/O.taihangensis were the highest(0.898) and lowest(0.125),respectively.The drought resistance order follows: S.spectabile I.lactea var.chinensis P.quinquefolia O.taihangensis S.officinalis.The results of cluster analysis shows S.spectabile and I.lactea var.chinensis were the most drought resistant plants,P.quinquefolia exhibited a medium level of drought resistance,and O.taihangensis and S.officinalis had poor drought resistance.