The nitrogen dynamics of plants can be quantified using the variation in their δ 15 N level. This reveals details of plant physiological characteristics and the relationship between plants and their growth conditions. To better understand plant nitrogen dynamics and the effects of external temperature changes on their nitrogen isotopic composition, we investigated the δ 15 N characteristics in Triticum aestivum and its mother soils during the plant's life cycle. We found that under field conditions, the plant's leaves and roots δ 15 N significantly changed. The δ 15 N values in Triticum aestivum changed from -1.6‰ to -8.1‰ for leaves and from -2.0‰ to -8.8‰ for roots, respectively. δ15 N values for both, the leaves and roots were positively correlated with temperature. However, the foliar δ 15 N corresponded more strongly to air temperature, while the root δ 15 N corresponded to soil temperature. δ 15 N values of leaf and root both changed around 0.2‰ in response to a 1 degree change in temperature. Plant roots or shoot material cannot reflect the whole plant δ 15 N values due to a considerable difference between the δ 15 N values of root and leaf. However, the variations in leaf and root δ 15 N provide useful proxies to trace seasonal plant nitrogen cycles.
Considering the frequent geological disaster in our country, it is imperative to construct the public service platform for geological disaster spatial information. Based on the growing demand for spatial information sharing by all sectors of society, government, the public, the paper summarizes and analyzes the background and existing issues of spatial information sharing. In line with the idea on spatial information resources put forward by the state, the paper discusses the target, construction ideas, design architecture of the platform and content on Geo-hazard spatial information sharing services platform, WMI as well as business process at the background of comprehensive and normative internet environment.
We dissolved 1-iodo-4-nitrobenzene in various solvents, including ethanol, benzene, toluene and dimethylacetamide, and prepared solution with different concentration from 10-2 M to 10-5 M. Epitaxial Au(111) film and graphite were used as substrates. Scanning tunneling microscope (STM) was used to observe structures of 1-iodo-4-nitrobenzene molecules on those substrates. Experimentally, we found that 1-iodo-4-nitrobenzene molecules constructed nanowires on graphite surface at room temperature in air. The mechanism of formation of nanowire is briefly discussed in this paper.
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