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Xu Z.-F.,CAS Chengdu Institute of Biology | Xu Z.-F.,University of Chinese Academy of Sciences | Xu Z.-F.,Key Laboratory of Sichuan Province | Tang Z.,CAS Chengdu Institute of Biology | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2010

With open top chamber (OTC) , this paper studied the effects of simulated warming on the activities of soil invertase, urease, catalase, polyphenol oxidase in two contrasting subalpine coniferous forests (a dragon spruce plantation and a natural conifer forest) in west Sichuan. The dynamic changes of soil temperature and soil moisture were monitored synchronously. In the whole growth season, simulated warming enhanced the daily mean temperature at soil depth 5 cm by 0. 61 X. in the plantation, and by 0. 55°C. in the natural forest. Conversely, the volumetric moisture at soil depth 10 cm was declined by 4. 10% and 2. 55% , respectively. Simulated warming also increased soil invertase, urease, catalase, and polyphenol oxidase activities. The interactive effect of warming and forest type was significant on soil urease and catalase, but not significant on soil invertase and polyphenol oxidase. The warming effect on soil catalase depended, to some extent, on season change. In all treatments, the soil enzyme activities in the natural forest were significantly higher than those in the plantation. The seasonal changes of test soil enzyme activities were highly correlated with soil temperature, but less correlated with soil moisture. This study indicated that warming could enhance soil enzyme activities, and the effect had definite correlations with forest type, enzyme category, and season change. The soil enzyme activities in the subalpine coniferous forests were mainly controlled by soil temperature rather than soil moisture. Source


Deng B.,Technology Center | Deng B.,University of Sichuan | Shen C.-H.,Technology Center | Shan X.-H.,Technology Center | And 4 more authors.
Journal of the Institute of Brewing | Year: 2012

Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyse microbial community evolution in the pit mud of cellars used for different periods of time in production of Chinese Luzhou-flavour liquor. The pit mud was collected from the cellars and the microbial DNA was extracted from the microbes in the pit mud. The Bf 968 primer was used for PCR-DGGE to analyse the variable region 6 (V6) to variable region 8 (V8) of the microbial 16S rDNA. It was found that the band number, dominance, diversity and similarity of the 16S rDNA were clearly different in the DGGE patterns, because of the great diversity expressed by the different microbial communities in the different-aged cellars. It is concluded that mutual collaboration and constraint exist between the different microbial communities in the different-aged cellars, and this relationship leads to an evolutional change in the structures and in the numbers of the microbial communities in the pit mud of the cellars. Changes become more obvious with increasing age of the liquor cellars. © 2012 The Institute of Brewing & Distilling. Source


Yin H.,CAS Chengdu Institute of Biology | Yin H.,Chinese Academy of Sciences | Yin H.,Key Laboratory of Sichuan Province | Xu Z.,CAS Chengdu Institute of Biology | And 7 more authors.
Applied Soil Ecology | Year: 2012

Tree species can exert a strong influence on rhizosphere nutrient cycling through root and rhizosphere processes and create feedback in the patterns of nutrient cycling in forest ecosystems. In this study, we conducted an experiment to compare the rhizosphere effects of two coniferous species on N transformation as well as their responses to experimental warming using infrared heaters in the Eastern Tibetan Plateau. We examined the potential net N mineralization and nitrification rates, N availability, and microbial biomass C (MBC) and N (MBN) in rhizosphere soils of Picea asperata and Abies faxoniana plots and compared them to bulk soils. The infrared heater increased both the mean air and the soil temperatures by 1.5°C and 2.1°C respectively. Potential net N mineralization and net nitrification rates were generally greater in rhizosphere soils for the two conifers than in bulk soil, especially in the warmed plots. This led to higher NH4 + and NO3 - concentrations in the rhizosphere soils. MBC and MBN were markedly higher in the rhizosphere soils relative to bulk soil in the study plots. In the control subplots of P. asperata, MBC, MBN, potential net N mineralization and net nitrification rates in the rhizosphere were 9.6%, 21.7%, 33.3% and 20.1% greater than in the bulk soil, respectively. MBC, MBN, potential net N mineralization and net nitrification rates in the control subplots of A. faxoniana, however, were 2.0%, 7.7%, 22.0% and 11.8% higher, respectively, in the rhizosphere than in the bulk soil; all of the variables were significantly lower than those of P. asperata subplots. Warming significantly promoted N transformation and nutrient availability by enhancing the rhizosphere priming effects for the two conifers, but the magnitudes of the rhizosphere effects on soil N transformation stimulated by warming were generally greater in P. asperata than in A. faxoniana subplots. Differences in the altered morphological and functional characteristics of the roots between the two species under experimental warming could be largely responsible for this variation. Taken together, the results indicated that the two species exhibited similar patterns but with considerably different magnitudes of rhizosphere effects on N transformations in response to experimental warming, implying different capacities of the two conifers to acquire nutrients and thereby altered the competitive and adaptive relationships between the tree species under climate change. © 2012 Elsevier B.V. Source


Zhang W.W.,Sichuan University | Zhang W.W.,Chengdu Medical College | Ye Z.M.,Sichuan University | Jin Y.,Sichuan University | And 5 more authors.
World Mycotoxin Journal | Year: 2014

Mycotoxins have a significant impact on human and animal health as well as economy and international trade. A number of steps have been taken to minimise mycotoxin contamination worldwide. China, one of the largest importers and exporters of food and animal feed, has implemented management strategies to protect consumers from mycotoxins and ensure safe trading of food and feed. The development and status of these management strategies are of interest to many stakeholders, however, no comprehensive review of these strategies has been published to date. The objective of this article is to review these strategies, including associated regulations, risk assessments, contamination monitoring practices, and processes for the supervision and management of associated production, distribution and consumption chains. There are 49 mycotoxin-related regulations in China; these include maximum levels for seven mycotoxins, standard methods for detecting 17 mycotoxins, and a code of practice for the prevention and reduction of mycotoxin contamination in cereals. Twelve mycotoxins found in daily food are covered by the Chinese contamination monitoring network. A new risk assessment organisation is required to systematically implement and manage food safety risk assessments in China. In addition, self-control by companies and daily supervisions and inspections by government departments are quite effective in preventing the consumption of mycotoxin-contaminated food and feed. This article provides information to all those who wish to understand more about the current safety management systems for combating mycotoxin contamination of food and feed in China. Source


Zeng T.,University of Sichuan | Zeng T.,Key Laboratory of Sichuan Province | Zhang X.,University of Sichuan | Lin H.B.,University of Sichuan | And 4 more authors.
Applied Mechanics and Materials | Year: 2011

The process of bubbles from formation to eruption was simulated by using the two-fluid model combined with the particle kinetic theory to investigate the flow characterization of gas-solid in a bubbling fluidized bed. The velocity distributions of solid-phase in different axial height were also studied. The results show that the numerical simulation method can success simulates the flow characterization of gas-solid bubbling fluidized bed. The flow characterization in bubbling fluidized bed is circulating flow structure, while the central region is upward flow and the wall region is downward flow. The simulation results agree with the experiment results. © (2011) Trans Tech Publications, Switzerland. Source

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