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61.
Shaoqiang Wang Jiangwen Fan Minghua Song Guirui Yu Lei Zhou Jiyuan Liu Huaping Zhong Lupeng Gao Zhongmin Hu Weixing Wu Ting Song 《Plant and Soil》2013,363(1-2):243-255
Background and aims
SOC inventory and soil δ13C were widely used to access the size of soil C pool and to indicate the dynamics of C input and output. The effects of climatic factors and soil physical characteristics and plant litter input on SOC inventory and soil δ13C were analyzed to better understand the dynamics of carbon cycling across ecosystems on the Qinghai-Tibetan Plateau.Methods
Field investigation was carried out along the two transects with a total of 1,875 km in length and 200 km in width. Sixty-two soil profiles, distributed in forest, meadow, steppe, and cropland, were stratified sampled every 10 cm from 0 to 40 cm.Results
Our result showed that SOC density in forest and meadows were much higher than in steppe and highland barley. In contrast, δ13C in forest and meadow were lower than in steppe and highland barley. Soil δ13C tended to enrich with increasing soil depth but SOC decline. SOC and δ13C (0–40 cm) were correlated with different climatic factors in different ecosystems, such that SOC correlated negatively with MAT in meadow and positively with MAP in steppe; δ13C correlated positively with MAT in meadow and steppe; and δ13C also tended to increase with increasing MAT in forest. Of the variation of SOC, 55.15 % was explained by MAP, pH and silt content and 4.63 % was explained by the interaction between MAT and pH across all the ecosystems except for the cropland. Meanwhile, SOC density explained 27.40 % of variation of soil δ13C.Conclusions
It is suggested that different climatic factors controlled the size of the soil C pool in different ecosystems on the Tibetan Plateau. SOC density is a key contributor to the variation of soil δ13C. 相似文献62.
青藏高原区域不同功能群植物氮磷生态化学计量学特征 总被引:3,自引:4,他引:3
生态化学计量学为揭示植物养分利用状况及植物对环境的适应策略提供了重要手段,研究不同功能群植物在区域尺度生态化学计量学特征中所产生的贡献,有助于揭示区域尺度植物元素特征的形成机制。已有研究多是从不同功能群植物元素生态化学计量学特征的比较上进行分析,未能对每种功能群植物元素含量随地理因子和气候因子的变化规律展开探讨。基于生态化学计量学理论,对青藏高原区域不同功能群植物(豆科、禾本科、莎草科、杂类草)叶片水平N、P元素含量随纬度、海拔、年降水量、年均温度的变化规律展开研究,探讨不同植物功能群在区域尺度植物生态化学计量学特征中所产生的贡献,尝试从植物功能群角度揭示青藏高原高寒区域N、P元素含量特征的形成机制。结果显示,1)不同功能群植物叶片元素含量差异显著,豆科植物N、P元素含量最高,禾本科植物N、P含量最低,N/P比值在不同功能群间差异不显著;2)随纬度变化,莎草科植物P元素及杂类草N元素含量变化显著;随海拔变化,豆科、禾本科植物及杂类草叶片N元素含量变化较为显著;随年降水量和年均温度的变化,杂类草和莎草科植物叶片N、P含量变化显著;3)莎草科植物N、P含量对纬度和降水的响应趋势与区域内所有植物叶片N、P含量对纬度和降水的响应趋势一致,豆科、禾本科及杂类草植物叶片元素含量对海拔和温度的响应趋势与区域内所有植物叶片元素平均含量对海拔和温度的响应趋势一致。研究表明,不同功能群植物元素特征对环境因子的响应不同,植物功能群组成对区域尺度植物生态化学计量学特征有重要作用,但在较大的植物结构层次上(如植物群落、生态系统、区域或全球尺度等),不同功能群植物之间的相互组合会抵消或掩盖掉某一类群的特性,从而对区域尺度植物元素特征的变化规律产生影响。 相似文献
63.
64.
Weijing Zhao Jiemin Pan Huaping Li Yajuan Huang Fang Liu Minfang Tao Weiping Jia 《PloS one》2016,11(2)
Aims
Serum cystatin C (CysC) has recently been shown to be associated with the incidence of type 2 diabetes mellitus (T2DM) and progression to the pre-diabetic state. The aim of this study was to explore the relationship between serum CysC and the risk of gestational diabetes mellitus (GDM) in Chinese pregnant women.Methods
This cross-sectional study consisted of 400 pregnant women including111 with GDM and 289 with normal glucose tolerance at 24–28 weeks of gestation. The subjects were further divided into four groups according to the CysC quartiles, and their clinical characteristics were compared. The serum CysC concentration was measured using immunoturbidimetry and the degree of insulin resistance was assessed by the homeostasis model assessment of insulin resistance (HOMA-IR).Results
Serum CysC levels were significantly higher in pregnant women with GDM than in the healthy pregnant women[1.0(0.8–1.8) vs 0.7(0.6–1.0), P<0.01). The Spearman’s correlation analysis showed that serum CysC was positively associated with HOMA-IR(r = 0.118, P<0.05) and the occurrence of GDM(r = 0.348, P<0.01). The pregnant women were divided into quartiles according to their serum CysC concentrations. Compared to the first quartile, pregnant women in Q2 (OR, 2.441; P = 0.025), Q3 (OR, 3.383; P = 0.001) and Q4 (OR, 5.516; P<0.001) had higher risk of GDM after adjusted for age, BMI, HbA1c and HOMA-IR. Further, with a rise in the serum CysC, there was an increasing trend in the HOMA-IR levels (P<0.05). A binary logistic regression analysis after adjusting for other confounding variables revealed a significant and independent association between serum CysC and GDM [OR = 14.269; 95% confidence interval, 4.977–40.908, P<0.01].The receiver operating characteristic curve analysis revealed that the optimal cutoff point for serum CysC to indicate GDM was 0.95mg/L.Conclusions
Serum CysC is significantly and independently associated with insulin resistance and GDM. It may be a helpful biomarker to identify the risk of GDM in Chinese pregnant women. 相似文献65.
66.
Nie L Tang M Zeng Y Jiang H Shi H Luo H Hu X Gao L Xi J Liu A Reppel M Hescheler J Liang H 《Biochemical and biophysical research communications》2012,418(1):74-80
BackgroundPrevailing data suggest that ATP-sensitive potassium channels (KATP) contribute to a surprising resistance to hypoxia in mammalian embryos, thus we aimed to characterize the developmental changes of KATP channels in murine fetal ventricular cardiomyocytes.MethodsPatch clamp was applied to investigate the functions of KATP. RT-PCR, Western blot were used to further characterize the molecular properties of KATP channels.ResultsSimilar KATP current density was detected in ventricular cardiomyocytes of late development stage (LDS) and early development stage (EDS). Molecular–biological study revealed the upregulation of Kir6.1/SUR2A in membrane and Kir6.2 remained constant during development. Kir6.1, Kir6.2, and SUR1 were detectable in the mitochondria without marked difference between EDS and LDS. Acute hypoxia–ischemia led to cessation of APs in 62.5% of tested EDS cells and no APs cessation was observed in LDS cells. SarcKATP blocker glibenclamide rescued 47% of EDS cells but converted 42.8% of LDS cells to APs cessations under hypoxia-ischemic condition. MitoKATP blocker 5-HD did not significantly influence the response to acute hypoxia–ischemia at either EDS or LDS. In summary, sarcKATP played distinct functional roles under acute hypoxia-ischemic condition in EDS and LDS fetal ventricular cardiomyocytes, with developmental changes in sarcKATP subunits. MitoKATP were not significantly involved in the response of fetal cardiomyocytes to acute hypoxia–ischemia and no developmental changes of KATP subunits were found in mitochondria. 相似文献
67.
69.
香蕉束顶病毒基因克隆和序列分析 总被引:11,自引:0,他引:11
对香蕉束顶病毒(BBTV)中国分离株DNA组份I(DNA-1)、外壳蛋白(CP)和运转蛋白(MP)基因进行了克隆和序列分析。BBTVDNA-1含有1103个核苷酸,与南太平洋和亚洲分离株分别有87%-88% 96.9-98%的核苷酸序列同源性。由DNA-1编码的复制酶含有186个在酸残基。与南太平洋和亚洲分离株分别有84.4%-95.8%和97.6%、98.0%的氨基酸序列同源性。外壳蛋白基因由5 相似文献
70.
Among the different nanostructures that have been demonstrated as promising materials for various applications, 3D nanostructures have attracted significant attention as building blocks for constructing high‐performance nanodevices. Particularly over the last decade, considerable research efforts have been devoted to designing, fabricating, and evaluating 3D nanostructures as electrodes for electrochemical energy conversion and storage devices. Although remarkable progress has been achieved, the performance of electrochemical energy devices based on 3D nanostructures in terms of energy conversion efficiency, energy storage capability, and device reliability still needs to be significantly improved to meet the requirements for practical applications. Rather than simply outlining and comparing different 3D nanostructures, this article systematically summarizes the general advantages as well as the existing and future challenges of 3D nanostructures for electrochemical energy conversion and storage, focusing on photoelectrochemical water splitting, photoelectrocatalytic solar‐to‐fuels conversion from nitrogen and carbon dioxide, rechargeable metal‐ion batteries, and supercapacitors. A comprehensive understanding of these advantages and challenges shall provide valuable guidelines and enlightenments to facilitate the further development of 3D nanostructured materials, and contribute to the achieving more efficient energy conversion and storage technologies toward a sustainable energy future. 相似文献