Recent Submissions

  • Acoustic mapping of submerged Stone Age sites – a HALD approach

    Grøn, Ole; Boldreel, Lars Ole; Smith, Morgan F.; Joy, Shawn; Tayong-Boumda, Rostand; Mäder, Andreas; Bleicher, Niels; Madsen, Bo; Cvikel, Deborah; Nilsson, Björn; et al. (MDPI, 2021-01-27)
    Acoustic response from lithics knapped by humans has been demonstrated to facilitate effective detection of submerged Stone Age sites exposed on the seafloor or embedded within its sediments. This phenomenon has recently enabled the non-invasive detection of several hitherto unknown submerged Stone Age sites, as well as the registration of acoustic responses from already known localities. Investigation of the acoustic-response characteristics of knapped lithics, which appear not to be replicated in naturally cracked lithic pieces (geofacts), is presently on-going through laboratory experiments and finite element (FE) modelling of high-resolution 3D-scanned pieces. Experimental work is also being undertaken, employing chirp sub-bottom systems (reflection seismic) on known sites in marine areas and inland water bodies. Fieldwork has already yielded positive results in this initial stage of development of an optimised Human-Altered Lithic Detection (HALD) method for mapping submerged Stone Age sites. This paper reviews the maritime archaeological perspectives of this promising approach, which potentially facilitates new and improved practice, summarizes existing data, and reports on the present state of development. Its focus is not reflection seismics as such, but a useful resonance phenomenon induced by the use of high-resolution reflection seismic systems.
  • Paraphyly of the genus Boehmeria (Urticaceae): a response to Liang et al. ‘Relationships among Chinese Boehmeria species and the evolution of various clade’

    Monro, Alexandre; Dodsworth, Steven; Fu, Long‑Fei; Friis, Ib; Wilmot-Dear, Christine M.; Maurin, Olivier; Royal Botanic Gardens, Kew; University of Bedfordshire; Chinese Academy of Sciences; Natural History Museum of Denmark (Springer, 2020-12-19)
    Boehmeria, as currently circumscribed, comprises 52 species and has a pantropical distribution. Liang et al. propose a sectional classification of Boehmeria based on the phylogenetic analysis of SNP data for 20 species and an additional 10 subspecific taxa of these at the rank of variety or form. They restrict their sampling to species documented in China. We found many shortcomings in the sampling and analyses which we feel have resulted in a misleading phylogeny for the genus and the economically important fibre-plant, Boehmeria nivea. By sampling only Chinese species of this genus for their in-group and using a single distantly related outgroup, Liang et al. have failed to capture the diversity of the genus and so erroneously concluded that it forms a monophyletic group. Previous published research clearly demonstrates that Boehmeria is paraphyletic and polyphyletic, comprising at least four monophyletic groupings most closely related to several genera within the Boehmerieae. For these reasons, the sections that Liang et al. (Ind Crops Prod 148:112092, 2020. propose for Boehmeria are not effective tools for its classification. The important fibre-plant, Boehmeria nivea, should therefore not be considered as part of the genus Boehmeria for the purposes of crop breeding, but as sister to Archiboehmeria. Breeding programmes for ramie should therefore focus on populations and germplasm of Archiboehmeria atrata. We conclude that poor taxon sampling, overlooking relevant molecular and taxonomic literature, internal conflict within their SNP data and the overinterpretation of low support values has resulted in the erroneous conclusion that Boehmeria represents a monophyletic or ‘natural’ genus.
  • Fiscal expenditures on science and technology and environmental pollution: evidence from China

    Xiong, Wanfang; Han, Yan; Crabbe, M. James C.; Yue, Xiao-Guang; Huazhong University of Science and Technology; Beijing Institute of Technology; Oxford University; Shanxi University; University of Bedfordshire; European University Cyprus; et al. (MDPI, 2020-11-25)
    Studying the driving factors of environmental pollution is of great importance for China. Previous literature mainly focused on the cause of national aggregate emission changes. However, research about the effect of fiscal expenditures on science and technology (FESTs) on environmental pollution is rare. Considering the large gap among cities in China, it is necessary to investigate whether and how FESTs affect environmental pollution among cities. We adopted three kinds of typical environmental pollutants including sulfur dioxide (SO2) emissions, wastewater emission, and atmospheric particulate matter less than 2.5 micrometers in diameter (PM2.5). Using the data of 260 prefecture-level cities over ten years in China, we found that FESTs play a significantly positive role in reducing sulfur dioxide (SO2) emissions and PM2.5 concentrations, but fail to alleviate wastewater emissions. Specifically, for every 1% increase in FESTs, SO2 emissions were reduced by 5.317% and PM2.5 concentrations were reduced by 5.329%. Furthermore, we found that FESTs reduced environmental pollution by impeding fixed asset investments and by promoting research and development activities (R&D). Moreover, the impacts of FESTs on environmental pollution varied across regions and sub-periods. Our results are robust to a series of additional checks, including alternative econometric specifications, generalized method of moments (GMM) analysis and overcoming potential endogeneity with an instrumental variable. Our findings confirm that government efforts can be effective on pollution control in China. Hence, all governments should pay more attention to FESTs for sustainable development and environmental quality improvements.
  • History and trends in ecological stoichiometry research from 1992 to 2019: a scientometric analysis

    Li, Hailiang; Crabbe, M. James C.; Chen, Haikui; Gansu Agricultural University; Oxford University; University of Bedfordshire; Shanxi University; North Minzu University (MDPI, 2020-10-27)
    Ecological stoichiometry (ES), as an ecological theory, provides a framework for studying various ecological processes, and it has been applied successfully in fields ranging from nutrient dynamics to biogeochemical cycling. Through the application of ES theory, researchers are beginning to understand many diverse ecological topics. The aim of this paper was to identify the main characteristics of ES, especially to clarify the evolution, and potential trends of this field for future ecological studies. We used CiteSpace software to conduct a bibliometric review of ES research publications from 1992 to 2019 extracted from the Web of Science. The results showed that the United States has been a major contributor to this field; approximately half of the top 15 academic institutions contributing to ES research were in the United States. Although the largest number of publications on ES were from China, the impact of these academic papers has thus far been less than that of the papers from other countries. Moreover, none of the top 15 authors or cited authors contributing to publications on ES from 1992 to 2019 were from China. ES research has developed rapidly and has changed from single-discipline ES studies to a multidisciplinary “auxiliary tool” used in different fields. Overall, ES shows great research potential and application value, especially for studies on nutrient cycling, ecosystem sustainability and biogeochemical cycling.
  • Energy management optimization of open-pit mine solar photothermal-photoelectric membrane distillation using a support vector machine and a non-dominated genetic algorithm

    Zhang, Sai; Lu, Caiwu; Jiang, Song; Lu, Shan; Crabbe, M. James C.; Xiong, Neal Naixue; Xi'an University of Architecture and Technology; Hong Kong University of Science and Technology; Oxford University; University of Bedfordshire; et al. (Institute of Electrical and Electronics Engineers, 2020-08-25)
    As a distributed energy source, open-pit mine solar photothermal-photoelectric membrane distillation can convert solar energy into heat and electrical energy to provide power for membrane distillation water purification system. In mine sewage treatment, the solar membrane distillation system has the advantages of high desalination rate, good water quality and low cost. However, this system has not been widely promoted and applied because of its high energy consumption and low membrane flux. Different operating parameters have a greater impact on the operating efficiency of the solar membrane distillation system. In this study, a natural cooling film distillation system was built, and the response surface method was used to analyze it, and a multi-objective optimization algorithm was used to optimize the operating conditions and improve the energy efficiency of the system. In our experiment, the hot end feed temperature, hot end feed flow rate, cold end cooling water flow rate, and membrane area were used as variables, and the membrane flux, thermal efficiency, and energy consumption values were investigated as target values. We used a support vector machine (SVM) with improved fitting, and substituted the fitting rediction model into the response surface method for the relationship between the variable and the target value collaborative analysis was followed by substituting the model into a non-dominated sorting genetic algorithm-II (NSGA-II). After the optimization operation, the optimal working conditions were obtained to improve the operating efficiency of the solar membrane distillation system, which will enable open-pit mine prosumers to realize intelligent management of solar energy generation, storage and consumption simultaneously.
  • Resolving relationships in an exceedingly young Neotropical orchid lineage using Genotyping-by-sequencing data

    Pérez-Escobar, Oscar Alejandro; Bogarin, Diego; Schley, Rowan; Bateman, Richard M.; Gerlach, Günter; Harpke, Dörte; Brassac, Jonathan; Fernández-Mazuecos, Mario; Dodsworth, Steven; Hagsater, Eric; et al. (Elsevier, 2019-11-14)
    Poor morphological and molecular differentiation in recently diversified lineages is a widespread phenomenon in plants. Phylogenetic relationships within such species complexes are often difficult to resolve because of the low variability in traditional molecular loci. Furthermore, biological phenomena responsible for topological incongruence such as Incomplete Lineage Sorting (ILS) and hybridisation complicate the resolution of phylogenetic relationships among closely related taxa. In this study, we employ a Genotyping-by-sequencing (GBS) approach to disentangle evolutionary relationships within a species complex belonging to the Neotropical orchid genus Cycnoches. This complex includes seven taxa distributed through Central America and the Colombian Chocó, and is nested within a clade estimated to have first diversified in the early Quaternary. Previous phylogenies inferred from few loci failed to provide support for internal relationships within the complex. Our Neighbour-net and coalescent-based analyses inferred from ca. 13,000 GBS loci obtained from 31 individuals belonging to six of the seven traditionally accepted Cycnoches taxa provided a robust phylogeny for this group. The genus Cycnoches includes three main clades that are further supported by morphological traits and geographic distributions. Similarly, a topology reconstructed through maximum likelihood (ML) inference of concatenated GBS loci produced results that are comparable with those reconstructed through coalescence and network-based methods. Our comparative phylogenetic informativeness analyses suggest that the low support evident in the ML phylogeny might be attributed to the abundance of uninformative GBS loci, which can account for up to 50% of the total number of loci recovered. The phylogenomic framework provided here, as well as morphological evidence and geographical patterns, suggest that the six entities previously thought to be different species or subspecies might actually represent only three distinct segregates. We further discuss the limited phylogenetic informativeness found in our GBS approach and its utility to disentangle relationships within recent and rapidly evolving species complexes. Our study is the first to demonstrate the utility of GBS data to reconstruct relationships within young (~2 Ma) Neotropical plant clades, opening new avenues for studies of species complexes that populate the species-rich orchid family.
  • Corporate social responsibility and maturity mismatch of investment and financing: evidence from polluting and non-polluting companies

    Bao, Xiaolan; Luo, Qiaosheng; Li, Sicheng; Crabbe, M. James C.; Yue, Xiao-Guang; Huazhong Agricultural University; Oxford University; University of Bedfordshire; Shanxi University; European University Cyprus; et al. (MDPI, 2020-06-18)
    We investigate the influence of corporate social responsibility (CSR) on the maturity mismatch of investment and financing from the perspective of both polluting and non-polluting companies. The results reveal that CSR performance can aggravate the maturity mismatch of investment and financing; and the e ect can be more serious in the polluting companies. At the same time, we find that CSR makes companies obtain more short-term debt. What is more, polluting companies perform more environmental responsibilities in the form of long-term investments than non-polluting companies. These phenomena exacerbate the maturity mismatch of investment and financing; and this e ect is only significant when polluting companies choose CSR mandatory disclosure. The impact of CSR on the maturity mismatch of investment and financing is more apparent in companies with lower value and at smaller scales. We show that companies should not only perform their CSR to maintain a balanced economic and ecological development, but also pay attention to the aggravation of the maturity mismatch of investment and financing.
  • Models for oil refinery waste management using determined and fuzzy conditions

    Zhumadillayeva, Ainur; Orazbayеv, Batyr; Santeyeva, Saya; Dyussekeyev, Kanagat; Li, Rita Yi Man; Crabbe, M. James C.; Yue, Xiao-Guang; L.N.Gumilyov Eurasian National University, Kazakhstan; Hong Kong Shue Yan University; Rajamangala University of Technology Rattanakosin, Thailand; et al. (MDPI, 2020-06-03)
    This study developed models to solve problems of optimisation, production, and consumption in waste management based on methods of system analysis. Mathematical models of the problems of optimisation and sustainable waste management in deterministic conditions and in a fuzzy environment were formulated. The income from production was maximised considering environmental standards that apply to the field of macroeconomics and microeconomics. The proposed approach used MANAGER software to formalise and solve the problem of revenue optimisation with production waste management to optimise the production of oil products with waste management at a specific technological facility of the Atyrau oil refinery in Kazakhstan. Based on the combined application of the principles of maximin and Pareto optimality, a formulation of the problem of production optimisation with waste management was obtained and a heuristic algorithm for solving the formulated fuzzy optimisation problem with waste management was developed.
  • Valuation impacts of environmental protection taxes and regulatory costs in heavy-polluting industries

    Tu, Wen-Jun; Yue, Xiao-Guang; Liu, Wei; Crabbe, M. James C.; Ningbo University; European University Cyprus; Porto Polytechnic; Qingdao University; Oxford University; University of Bedfordshire; et al. (MDPI, 2020-03-20)
    In 2016, the issue of the Environmental Protection Tax Law indicated the enhancement of environmental protection in China. This study examines the market reaction to firms in heavy-polluting industries, and the effects of external legal institutional quality and internal environmental disclosure on firm value around the passage of Environmental Protection Tax Law. Using an event study approach coupled with ordinary least square regressions, the researchers find a significantly negative market reaction to firms in heavy-polluting industries, but this negative reaction varies depending on the expected increase in future regulatory costs. Specifically, the above negative reaction is stronger when the firm reveals that itself or its subsidiary belongs to heavy-polluting industry, however it would be mitigated when a firm is in a region with better quality of legal institutions or discloses environmental improvement activities. Overall, the results are consistent with the market perceiving that the environmental protection tax law enacted would increase regulatory costs for firms in heavy-polluting industries, and also show the higher-quality regional legal institutions and more efforts on environmental protection could relieve the market’s pessimism caused by uncertainty.
  • Isolation and identification of cobalt- and caesium-resistant bacteria from a nuclear fuel storage pond

    Dekker, Linda; Osborne, Thomas H.; Santini, Joanne M.; University College London (Wiley, 2014-10-31)
    One of the issues facing the nuclear power industry is how to store spent nuclear fuel which is contaminated with radionuclides produced during nuclear fission, including caesium ((134)Cs(+), (135)Cs(+) and (137)Cs(+)) and cobalt ((60)Co(2+)). In this study, we have isolated Co(2+)- and Cs(+)-resistant bacteria from water collected from a nuclear fuel storage pond. The most resistant Cs(+) and Co(2+) isolates grew in the presence of 500 mM CsCl and 3 mM CoCl2. Strain Cs67-2 is resistant to fourfold more Cs(+) than Cupriavidus metallidurans str. CH34 making it the most Cs(+)-resistant strain identified to date. The Cs(+)-resistant isolates were closely related to bacteria in the Serratia and Yersinia genera, while the Co(2+)-resistant isolates were closely related to the Curvibacter and Tardiphaga genera. These new isolates could be used for bioremediation.
  • Isolation of an arsenate-respiring bacterium from a redox front in an arsenic-polluted aquifer in West Bengal, Bengal Basin

    Osborne, Thomas H.; McArthur, John H.; Sikdar, Pradip K.; Santini, Joanne M.; University College London; Indian Institute of Social Welfare and Business Management (American Chemical Society, 2015-03-03)
    Natural pollution of groundwater by arsenic adversely affects the health of tens of millions of people worldwide, with the deltaic aquifers of SE Asia being particularly polluted. The pollution is caused primarily by, or as a side reaction of, the microbial reduction of sedimentary Fe(III)-oxyhydroxides, but the organism(s) responsible for As release have not been isolated. Here we report the first isolation of a dissimilatory arsenate reducer from sediments of the Bengal Basin in West Bengal. The bacterium, here designated WB3, respires soluble arsenate and couples its reduction to the oxidation of acetate; WB3 is therefore implicated in the process of arsenic pollution of groundwater, which is largely by arsenite. The bacterium WB3 is also capable of reducing dissolved Fe(III) citrate, solid Fe(III)-oxyhydroxide, and elemental sulfur, using acetate as the electron donor. It is a member of the Desulfuromonas genus and possesses a dissimilatory arsenate reductase that was identified using degenerate polymerase chain reaction primers. The sediment from which WB3 was isolated was brown, Pleistocene sand at a depth of 35.2 m below ground level (mbgl). This level was some 3 cm below the boundary between the brown sands and overlying reduced, gray, Holocene aquifer sands. The color boundary is interpreted to be a reduction front that releases As for resorption downflow, yielding a high load of labile As sorbed to the sediment at a depth of 35.8 mbgl and concentrations of As in groundwater that reach >1000 μg/L.
  • Microbial oxidation of arsenite in a subarctic environment: diversity of arsenite oxidase genes and identification of a psychrotolerant arsenite oxidiser

    Osborne, Thomas H.; Jamieson, Heather E.; Hudson-Edwards, Karen A.; Nordstrom, D. Kirk; Walker, Stephen R.; Ward, Seamus A.; Santini, Joanne M. (Biomed Central, 2010-07-30)
    Arsenic is toxic to most living cells. The two soluble inorganic forms of arsenic are arsenite (+3) and arsenate (+5), with arsenite the more toxic. Prokaryotic metabolism of arsenic has been reported in both thermal and moderate environments and has been shown to be involved in the redox cycling of arsenic. No arsenic metabolism (either dissimilatory arsenate reduction or arsenite oxidation) has ever been reported in cold environments (i.e. < 10°C).
  • Genome sequence of the mycotoxigenic crop pathogen Fusarium proliferatum strain ITEM 2341 from date palm

    Almiman, Bandar F.; Shittu, Taiwo Adewale; Muthumeenakshi, Sreenivasaprasad; Baroncelli, Riccardo; Sreenivasaprasad, Surapareddy; University of Bedfordshire; University of Salamanca (American Society for Microbiology, 2018-09-06)
    Fusarium proliferatum is a widely distributed fungal pathogen associated with more than 26 crop species important in global food security. Its strong mycotoxigenic capability with potential impacts on human and animal health is well recognized. In this work, we report the draft genome sequence of F. proliferatum strain ITEM 2341, originally isolated from date palm, providing a platform for further comparative and functional genomic investigations.
  • Water use for shale gas extraction in the Sichuan Basin, China

    Wang, Jianliang; Liu, Mingming; Bentley, Yongmei; Feng, Lianyong; Zhang, Chunhua; China University of Petroleum; University of Bedfordshire; Economics & Technology Research Institute, Beijing (Elsevier, 2018-08-07)
    This study investigates the use of water for extracting shale gas in the Sichuan Basin of China. Both net water use and water intensity (i.e., water use per unit of gas produced) of shale wells are estimated by applying a process-based life cycle inventory (LCI) model. The results show that the net water use and water intensity are around 24500 m3/well and 1.9 m3 water/104m3 gas respectively, and that the fracturing and completion stage of shale gas extraction accounts for the largest share in net water use. A comparison shows that China's water use for shale gas extraction is generally higher than that of other countries. By considering the predicted annual drilling activities in the Sichuan Basin, we find that the annual water demand for shale gas development is likely to be negligible compared to total regional water supply. However, considering the water demand for shale gas extraction and the water demand from other sectors may make water availability a significant concern for China's shale gas development in the future.
  • Sustainability assessment of bioenergy from a global perspective: a review

    Wang, Jianliang; Yang, Yuru; Bentley, Yongmei; Geng, Xu; Liu, Xiaojie; China University of Petroleum; University of Bedfordshire; Chinese Academy of Sciences (MDPI, 2018-08-01)
    Bioenergy, as a renewable energy resource, is expected to see significant development in the future. However, a key issue that will affect this trend is sustainability of bioenergy. There have been many studies on this topic, but mainly focusing on only one- or two-dimensions of the issue, and also with much of the literature directed at studies of European regions. To help understand the wider scope of bioenergy sustainability, this paper reviews a broad range of current research on the topic, and places the literature into a multi-dimensional framework covering the economic, environmental and ecological, social, and land-related aspects of bioenergy sustainability, as well as a geographical analysis of the areas for which the studies have been carried out. The review indicates that it is hard to draw an overall conclusion on the sustainability of bioenergy because of limited studies or contradictory results in some aspects. In addition, this review shows that crop-based bioenergy and forest bioenergy are seen as the main sources of bioenergy, and that most studies discuss the final utilization of bioenergy as being for electricity generation. Finally, research directions for future study are suggested, based on the literature reviewed here.
  • Salicylic acid collaborates with gene silencing to tomato defense against tomato yellow leaf curl virus (TYLCV)

    Li, Yunzhou; Muhammad, Tayab; Wang, Yong; Zhang, Dalong; Crabbe, M. James C.; Liang, Yan; Northwest A&F University; Guizhou University; Shangdong Agricultural University; University of Oxford; et al. (Pakistan Botanical Society, 2018-07-10)
    Antiviral research in plants has been focused on RNA silencing (i.e. RNA interference), and several studies suggest that salicylic acid (SA)-mediated resistance is a key part of plant antiviral defense. However, the antiviral defense mechanism of SA-mediation is still unclear, and several recent studies have suggested a connection between SA-mediated defense and RNA silencing, which needs further characterization in TYLCV infection. In this study, both SA-mediated defense and the RNA silencing mechanism were observed to play an important role in the antiviral response against TYLCV. First, we found that SA application enhanced the resistance to TYLCV in tomato plants. The expression of RNA-silencing-related genes, such as SlDCL1, SlDCL2, SlDCL4, SlRDR2, SlRDR3a, SlRDR6a, SlAGO1, and SlAGO4, were significantly triggered by exogenous SA application and inoculation with TYLCV, respectively. Furthermore, silencing of SlDCL2, SlDCL4 in tomato resulted in attenuated resistance to TYLCV, and reduced the expression of defense-related genes (SlPR1 and SlPR1b) in SA-mediated defense after infection with TYLCV, particularly in SlDCL2/SlDCL4-silenced plants. Taken together, we conclude that SA collaborates with gene silencing in tomato defense against TYLCV.
  • Scenarios for the development of smart grids in the UK: literature review

    Xenias, Demitrios; Axon, Colin; Balta-Ozkan, Nazmiye; Cipcigan, Liana; Connor, Peter; Davidson, Rosemary; Spence, Alexa; Taylor, Gary; Whitmarsh, Lorraine (UKERC, 2014-01-01)
    Smart grids are expected to play a central role in any transition to a low-carbon energy future, and much research is currently underway on practically every area of smart grids. However, it is evident that even basic aspects such as theoretical and operational definitions, are yet to be agreed upon and be clearly defined. Some aspects (efficient management of supply, including intermittent supply, two-way communication between the producer and user of electricity, use of IT technology to respond to and manage demand, and ensuring safe and secure electricity distribution) are more commonly accepted than others (such as smart meters) in defining what comprises a smart grid. It is clear that smart grid developments enjoy political and financial support both at UK and EU levels, and from the majority of related industries. The reasons for this vary and include the hope that smart grids will facilitate the achievement of carbon reduction targets, create new employment opportunities, and reduce costs relevant to energy generation (fewer power stations) and distribution (fewer losses and better stability). However, smart grid development depends on additional factors, beyond the energy industry. These relate to issues of public acceptability of relevant technologies and associated risks (e.g. data safety, privacy, cyber security), pricing, competition, and regulation; implying the involvement of a wide range of players such as the industry, regulators and consumers. The above constitute a complex set of variables and actors, and interactions between them. In order to best explore ways of possible deployment of smart grids, the use of scenarios is most adequate, as they can incorporate several parameters and variables into a coherent storyline. Scenarios have been previously used in the context of smart grids, but have traditionally focused on factors such as economic growth or policy evolution. Important additional socio-technical aspects of smart grids emerge from the literature review in this report and therefore need to be incorporated in our scenarios. These can be grouped into four (interlinked) main categories: supply side aspects, demand side aspects, policy and regulation, and technical aspects. 
  • Dr. Yang Zhong: an explorer on the road forever

    Chen, Fan; Lu, Bao-Rong; Crabbe, M. James C.; Zhao, Jiayuan; Zhong, Bo-jian; Geng, Yu-peng; Zheng, Yufang; Wang, Hong-yan; Chinese Academy of Sciences; Fudan University; et al. (Springer, 2017-12-30)
    On the morning of September 25th 2017, grievous news spread from the remote Ordos region of Inner Mongolia to Fudan University campus in Shanghai. Professor Yang Zhong, a famous botanist and the Dean of Fudan University’s graduate school, passed away in a tragic car accident while on a business trip.
  • Seasonal variations in carbon, nitrogen and phosphorus concentrations and C:N:P stoichiometry in the leaves of differently aged Larix principis-rupprechtii Mayr. plantations

    Li, Hailiang; Crabbe, M. James C.; Xu, Fuli; Wang, Weiling; Niu, Ruilong; Gao, Xing; Zhang, Pei; Chen, Haikui; Northwest A & F University, Yangling; University of Oxford; et al. (MDPI, 2017-09-30)
    The concentrations and stoichiometry of certain elements (carbon, nitrogen and phosphorus) are critical to the maintenance of plant functional and environmental adaptation during plant growth. We explore how the concentrations of C, N and P and the ratios of C:N, C:P, and N:P in the leaves of differently aged Larix principis-rupprechtii Mayr. plantations changed with growing season and stand age from 2012 to 2015 in the Qinling Mountains, China. The results showed that the element concentration and stoichiometric ratios in leaves were significantly affected by sampling month, stand age and sampling year; and multiple correlations with stand age were observed in different growing seasons. Compared to global element concentrations and stoichiometry in plants, the leaves of larch stands in the study region had higher C and P concentrations and C:N and C:P ratios but lower N concentrations and N:P ratios than global levels. The leaf N:P ratios of all of the larch stands were generally less than 14, suggesting that the growth of larch stands was limited by N in the study region. Our study facilitates the management and restoration of forest plantation and provides a valuable contribution to the global pool of leaf nutrition and stoichiometry data.
  • Seasonal variations in carbon, nitrogen and phosphorus concentrations and C:N:P stoichiometry in different organs of a Larix principis-rupprechtii Mayr. plantation in the Qinling Mountains, China

    Li, Haliang; Crabbe, M. James C.; Xu, Fuli; Wang, Weiling; Ma, Lihua; Niu, Ruilong; Gao, Xing; Li, Xingxing; Zhang, Pei; Ma, Xin; et al. (Public library of science, 2017-09-22)
    Understanding how concentrations of elements and their stoichiometry change with plant growth and age is critical for predicting plant community responses to environmental change. Weusedlong-term field experiments to explore how the leaf, stem and root carbon (C), nitrogen (N) and phosphorous (P) concentrations and their stoichiometry changed with growth and stand age in a L.principis-rupprechtii Mayr. plantation from 2012–2015 in the Qinling Mountains, China. Our results showed that the C, N and P concentrations and stoichiometric ratios in different tissues of larch stands were affected by stand age, organ type andsampling month and displayed multiple correlations with increased stand age in different growing seasons. Generally, leaf C and N concentrations were greatest in the fast-growing season, but leaf P concentrations were greatest in the early growing season. However, no clear seasonal tendencies in the stem and root C, N and P concentrations were observed with growth. In contrast to N and P, few differences were found in organ-specific C concentrations. Leaf N:P was greatest in the fast-growing season, while C:N and C:P were greatest in the late-growing season. No clear variations were observed in stem and root C:N, C:P andN:Pthroughout the entire growing season, but leaf N:P was less than 14, suggesting that the growth of larch stands was limited by N in our study region. Compared to global plant element concentrations and stoichiometry, the leaves of larch stands had higher C, P, C:NandC:PbutlowerNandN:P,andtherootshadgreater PandC:NbutlowerN,C:Pand N:P. Our study provides baseline information for describing the changes in nutritional elements with plant growth, which will facilitates plantation forest management and restoration, and makes avaluable contribution to the global data pool on leaf nutrition and stoichiometry.

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