Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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Mineralogical and morphological properties of individual dust particles in ice cores from the Tibetan Plateau
No full textUsing a field emission scanning electron microscope and energy-dispersive X-ray spectrometer (FESEM-EDS), individual insoluble dust particles in ice cores recovered from the northern (Dunde), western (Murtagata) and south-eastern (Palong-Zangbo) Tibetan Plateau were analysed in order to reveal the mineralogical and morphological characteristics of the analogue of long-range transported Asian dust. The results reveal that the dust particles are mainly composed of quartz (17-36%, number abundance), clay (37-48%) and feldspar (12-18%). Illite and chlorite are the dominant clay species, while kaolinite is rarely observed. For the three sites, regional differences in the mineral assemblages are significant, in particular the abundance of quartz, chlorite and muscovite species, reflecting the regional provenance of these dust particles and the climatic regime in their source areas. Oxide ratios in clays indicate different weathering strengths of the particles in their source regions, with a higher K2O/(SiO2 + Al2O3) in the western and northern Tibetan Plateau. The individual particles have modes of 1.48 and 1.53 in the aspect ratio and circularity distribution respectively. No significant relationship between aspect ratio and circularity was found. Quartz and feldspar particles have a narrow aspect ratio distribution. Muscovite particles have the coarsest grain size, while chlorite particles have the finest
Parental dietary seleno-L-methionine exposure and resultant offspring developmental toxicity
No full textSelenium (Se) leaches into water from agricultural soils and from storage sites for coal fly ash. Se toxicity causes population and community level effects in fishes and birds. We used the laboratory aquarium model fish, Japanese medaka (Oryzias latipes), an asynchronous breeder, to determine aspects of uptake in adults and resultant developmental toxicity in their offspring. The superior imaging properties of the model enabled detailed descriptions of phenotypic alterations not commonly reported in the existing Se literature. Adult males and females in treatment groups were exposed, separately and together, to a dry diet spiked with 0, 12.5, 25, or 50 mu g/g (dry weight) seleno-L-methionine (SeMet) for 6 days, and their embryo progeny collected for 5 days, maintained under controlled conditions and observed daily for hatchability, mortality and/or developmental toxicity. Sites of alteration included: craniofacial, pericardium and abdomen (Pc/Ab), notochord, gall bladder, spleen, blood, and swim bladder. Next, adult tissue Se concentrations (liver, skeletal muscle, ovary and testis) were determined and compared in treatment groups of bred and unbred individuals. No significant difference was found across treatment groups at the various SeMet concentrations; and, subsequent analysis compared exposed vs. control in each of the treatment groups at 10 dpf. Increased embryo mortality was observed in all treatment groups, compared to controls, and embryos had a decreased hatching rate when both parents were exposed. Exposure resulted in significantly more total altered phenotypes than controls. When altered phenotypes following exposure of both parents were higher than maternal only exposure, a male role was suggested. The comparisons between treatment groups revealed that particular types of phenotypic change may be driven by the sex of the exposed parent. Additionally, breeding reduced Se concentrations in some adult tissues, specifically the liver of exposed females and skeletal muscle of exposed males. Detailed phenotypic analysis of progeny from SeMet exposed parents should inform investigations of later life stages in an effort to determine consequences of early life exposure. (C) 2015 Elsevier B.V. All rights reserved
The small-scale structure of a soil mite metacommunity
No full textThe metacommunity theory has advanced our understanding of how local communities are structured at multiple scales. However, few studies have addressed the distribution patterns of the metacommunity at a small scale, particularly for those organisms living in belowground ecosystems. Using a combination of the elements of metacommunity structure (EMS) and the null model analyses, the small-scale (50 m) spatial pattern of a soil mite metacommunity was identified in a temperate forest in 2012 and 2013. This study evaluated whether species replace each other across consistent environmental gradients and whether a significant competitive structure exists in the entire community. According to the results of EMS analysis, the soil mite metacommunity showed a Clementsian structure (a grouped distribution of species along environmental gradients), which was significantly correlated with moisture in 2012 and associated with moisture and food resources in 2013. Moreover, the patterns of the soil mite meta community were similar in both years. Based on the results of the null model analysis, a non-random co-occurred pattern with more significantly aggregated species pairs and the Pianka's overlap index, which was significantly larger than the randomness model, were detected in each year, indicating a noncompetitive community. In conclusion, the study indicated that the environmental filtering with moisture and food resources was an important driver in shaping the soil mite metacommunity into a small-scale Clementsian structure, while interspecific competition was likely not influential. (C) 2016 Elsevier Masson SAS. All rights reserved
Two new species of Austrophthiracarus (Acari: Oribatida: Phthiracaridae) from Capleston Biological Reserve in New Zealand
No full textIn this study, two new species of Austrophthiracarus (Oribatida: Phthiracaridae) from Capleston Biological Reserve, New Zealand, Austrophthiracarus paracronadunsp. nov. and Austrophthiracarus vestigiussp. nov., are described and illustrated. A new name Austrophthiracarus neonominatus is proposed for the species Austrophthiracarus parapulchellus Niedbala, 2016. An updated key to all known species of Austrophthiracarus in New Zealand is provided
Variation in Total Dissolved Iron Output and Iron Species During Extreme Rainfall Events
No full textDue to climate changes, the occurrence of extreme rainfall events (EREs) has been increasing worldwide and is expected to affect the output of total dissolved iron (TDFe) significantly. EREs occurred in the Songhua River Basin in 2013. To study the effects of EREs on the TDFe output and iron species, water samples were collected to analyze both TDFe concentration and the water quality. Filtration and ultrafiltration methods were employed to analyze the iron speciation according to the molecular weights of the TDFe species. The results showed that the TDFe concentration ranged from 0.46 to 1.10 mg/L (0.69 mg/L on average), and was increased significantly compared with that observed during the regular flood seasons from 2008 to 2012. The TDFe output reached 3.59 x 10(4) tons during EREs, almost equal to the annual output level in the Songhua River. Species analysis indicated that complexed iron at a low-molecular-weight was the dominant species during the EREs. The impulse of the TDFe output can be attributed to a hydrological connection to riparian wetlands and iron-rich terrestrial runoff, and it may exert an influence on the water quality and alter the transport and cycling of other chemicals (e.g., trace elements, nitrogen, and phosphate) in the Songhua River
Yield-density relationships of above- and belowground organs in Allium cepa var. aggregatum populations
No full textThe quantitative response of yield to density in plant populations has been an important focus of both theoretical research and empirical research. Most studies on yield-density effects have focused mainly on aboveground plant parts, and rarely on various plant organs and belowground parts. We tested the hypothesis that yield-density effects of belowground parts are different from those for aboveground parts. Bulbs of Allium cepa var. aggregatum were sown at five densities at the Pasture Ecology Research Station, western Jilin Province, China. We harvested populations at four different points in time and analyzed yield-density relationships of above- versus belowground parts and component organs. A hyperbolic model provided a very good fit to above- and belowground biomass, as well as the biomass of specific organs throughout the experiment. Aboveground and leaf biomass achieved constant final yield, but stand stem and root biomass increased monotonically with increasing sowing density. Belowground and specifically bulb yield was highest at intermediate densities at the later harvests. Constant final yield may be widely applicable to total biomass production by a population, but it does not apply to specific organs, such as stems, roots, or bulbs. Asymptotic leaf biomass reached its asymptote earlier than that of other aboveground parts. The effect of density on A. cepa var. aggregatum organs is a consequence of allocation of photosynthate to different organs in response to competition. Yield-density effects are different above- and belowground as a result of the different mechanisms of competition, constrained by the functional relationship between above- and belowground organs
美国湿地保护制度变迁研究
No full text本文提出了分析湿地保护制度变迁的理论框架,使不同国家的湿地保护制度研究能在统一语境下比较。首先基于科学计量学和系统研究方法筛选出公众、科学、政府和法律为影响湿地保护制度变迁的四个关键要素,并依赖博弈论工具建立了分析美国湿地保护制度的理论架构。基于这一架构,本文对包括关键利益相关者、政策执行路径、政策工具和管理挑战等内容的美国湿地政策史进行了讨论。对美国湿地保护制度的演化进行了四阶断之划分:“西进运动”与全民开垦(1900年之前)、“水鸟保护”与公众参与(1900-1970年)、核心法律与科学研究(1971-1980年)和完善制度与新的挑战(1980年至今)。分析得出如下结论:在湿地保护制度中,公众是源头、科学是前提、有效的政府管治和将湿地保护的规则和与政策制度化是关键。通过借鉴美国湿地保护制度变迁研究,本文构建了湿地保护制度变迁的“竹节模式”经验性模型,揭示了各动因之间的作用机理。虽然美国湿地保护制度也面临着公众教育、科学定义和政府管辖权等挑战,但中国的湿地管理者与政策制定者仍可从美国湿地政策执行的历史背景中吸取经验。同时本文的理论分析结构也可为自然资源及管理策略的研究提供参考
蓝靛果忍冬(Lonicer acaerulea L.)果实中内源酚类物质抗氧化性能检测方法的研究进展
No full text蓝靛果忍冬(Lonicer acaerulea L.)是一种优质的药食同源类浆果,因其果实中富含酚类物质而具有明显的抗氧化功能并具有抗病、杀菌等功效。介绍了蓝靛果忍冬果实提取物中内源酚类物质的组成,并从直接检测和间接检测两方面综述了其抗氧化性能检测方法的研究进展,同时对未来内源酚类物质抗氧化性能的检测方法进行展望,以期为我国蓝靛果忍冬果实产品的开发和利用提供参考
植物对铁元素吸收的分子调控机制研究进展
No full text铁是植物正常生命活动所必需的微量矿质元素, 在光合作用、呼吸作用等诸多生理代谢过程中发挥着重要的作用。虽然铁在地壳中含量丰富, 但因其在大多数类型土壤中利用率低, 导致植物缺铁现象比较普遍。植物在长期的进化过程中,演化出一套完整的铁吸收、运输和分子调控的系统。近年来, 国际上在揭示植物铁吸收、运输和储存的机制方面取得很大研究进展, 本文主要就植物对铁元素吸收分子调控机制的研究进展进行了综述, 以期为全面了解植物铁代谢的分子机制进行作物分子设计育种提供帮助