27 research outputs found

    Salinity effect and seed priming treatments on the germination of Suaeda salsa in the tidal marsh of the Yellow River estuary

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    The effects of salinity and seed priming treatments (hydropriming, water, KNO3 and KH2PO3) on the germination of the euhalophyte Suaeda salsa in intertidal zone of the Yellow River estuary were investigated. Results show that the seed germination percentage decreased with increasing NaCl concentration, and at the high NaCl level (800 mM), the lowest germination percentage was recorded. At the low NaCl levels, the highest germination rate was observed on day two and the seedling length was promoted slightly. In contrast, the germination delayed and the seedling length decreased at the high salinity. According to the survival functions, we also found that, at the low salinity, the seeds germinated quickly at the initial days and then the germination rate decreased, while few seeds germinated at the initial days at the high salinity. From the results of germination percentage and seedling length, we found that the effect of Yellow river water on germination was similar to the 400 mM NaCl. For priming treatments, the hydropriming has no promotion to the seeds germination, but it promoted the seedling growth at the river water and 400 mM NaCl. Seeds primed with KNO3 could improve the germination at the low salinity, while priming with KH2PO4 could improve the seedling growth at the high salinity, indicating that seed priming with proper nutrient (N, P) solutions could improve the germination or seedling growth as the nutrient (N, P) availability in the soil of S. salsa marsh was very limited.Keywords: Suaeda salsa, germination, salinity, priming, Yellow River estuar

    Structural Evolution of Chemically-Driven RuO2 Nanowires and 3-Dimensional Design for Photo-Catalytic Applications

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    Growth mechanism of chemically-driven RuO2 nanowires is explored and used to fabricate three-dimensional RuO2 branched Au-TiO2 nanowire electrodes for the photostable solar water oxidation. For the real time structural evolution during the nanowire growth, the amorphous RuO2 precursors (Ru(OH)(3)center dot H2O) are heated at 180 degrees C, producing the RuO2 nanoparticles with the tetragonal crystallographic structure and Ru enriched amorphous phases, observed through the in-situ synchrotron x-ray diffraction and the high-resolution transmission electron microscope images. Growth then proceeds by Ru diffusion to the nanoparticles, followed by the diffusion to the growing surface of the nanowire in oxygen ambient, supported by the nucleation theory. The RuO2 branched Au-TiO2 nanowire arrays shows a remarkable enhancement in the photocurrent density by approximately 60% and 200%, in the UV-visible and Visible region, respectively, compared with pristine TiO2 nanowires. Furthermore, there is no significant decrease in the device's photoconductance with UV-visible illumination during 1 day, making it possible to produce oxygen gas without the loss of the photoactvity.close1

    Pt nanoparticles modified by rare earth oxides: Electronic effect and influence to catalytic hydrogenation of 3-phenoxybenzaldehyde

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    The rare earth elements (La, Ce, Nd, Sm, Pr, and Gd) modified Pt/Al2O3 catalysts were prepared by the colloidal deposition and chemical reduction methods, respectively. Pt nanoparticles with average size 3 +/- 0.5 nm were uniformly dispersed on the surface of Al2O3 for the samples prepared by the colloidal deposition method, which exhibited higher activities in the hydrogenation of 3-phenoxybenzadehyde than the corresponding samples prepared by chemical reduction method. Moreover, except Gd, the catalysts modified by rare earth elements showed better catalytic performance than unmodified Pt/Al2O3. For Pt-Ce/Al2O3 catalyst, when the weight percent of Pt and Ce was 0.5 and 0.25, respectively, the hydrogenation conversion of 3-phenoxybenzaldehyde was 97.3% after 6 h reaction. This activity improvement is due to the electronic interaction between Pt and rare earth elements, which was investigated by X-ray photoelectron spectroscopy. (C) 2013 Elsevier Ltd. All rights reserved

    China's coastal wetlands: Conservation history, implementation efforts, existing issues and strategies for future improvement

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    China has approximately 5.80 x 10(6) ha coastal wetlands by 2014, accounting for 10.82% of the total area of natural wetlands. Healthy coastal wetland ecosystems play an important role in guaranteeing the territory ecological security and the sustainable development of coastal zone in China. In this paper, the natural geography and the past and present status of China's coastal wetlands were introduced and the five stages (1950s-1970s, 1980s-1991, 1992-2002, 2003-2010 and 2011-present) of China's coastal wetlands conservation from the foundation of the People's Republic in 1949 to present were distinguished and reviewed. Over the past decades, China has made great efforts in coastal wetland conservation, as signified by the implementation of coastal wetland restoration projects, the construction of coastal wetland nature reserves, the practice of routine ecological monitoring and two national wetland surveys, the promulgation of local wetland conservation statutes and specific regulations, the coordination mechanism to enhance management capacity, the wide development of coastal wetland research and public participation, and the extensive communication to strengthen international cooperation. Nonetheless, six major issues recently emerged in China's coastal wetland conservation are evidently existed, including the increasing threats of pollution and human activities, the increasing adverse effects of threaten factors on ecosystem function, the increasing threats of coastal erosion and sea-level rising, the insufficient funding for coastal wetlands conservation, the imperfect legal and management system for coastal wetlands, and the insufficient education, research and international cooperation. Although the threats and pressures on coastal wetlands conservation are still apparent, the future of China's coastal wetlands looks promising since the Chinese government understands that the sustainable development in coastal zone requires new attitudes, sound policies and concerted efforts at all levels. The major strategies for future improvement of China's coastal wetland conservation include: exploring effective measures in response to major threaten factors; improving the conservation and compensation system for coastal wetlands; strengthening coastal wetland legislation and management; increasing funds for coastal wetland conservation and research; and Strengthening coastal wetland education and international cooperation. (C) 2015 Elsevier Ltd. All rights reserved.China has approximately 5.80 x 10(6) ha coastal wetlands by 2014, accounting for 10.82% of the total area of natural wetlands. Healthy coastal wetland ecosystems play an important role in guaranteeing the territory ecological security and the sustainable development of coastal zone in China. In this paper, the natural geography and the past and present status of China's coastal wetlands were introduced and the five stages (1950s-1970s, 1980s-1991, 1992-2002, 2003-2010 and 2011-present) of China's coastal wetlands conservation from the foundation of the People's Republic in 1949 to present were distinguished and reviewed. Over the past decades, China has made great efforts in coastal wetland conservation, as signified by the implementation of coastal wetland restoration projects, the construction of coastal wetland nature reserves, the practice of routine ecological monitoring and two national wetland surveys, the promulgation of local wetland conservation statutes and specific regulations, the coordination mechanism to enhance management capacity, the wide development of coastal wetland research and public participation, and the extensive communication to strengthen international cooperation. Nonetheless, six major issues recently emerged in China's coastal wetland conservation are evidently existed, including the increasing threats of pollution and human activities, the increasing adverse effects of threaten factors on ecosystem function, the increasing threats of coastal erosion and sea-level rising, the insufficient funding for coastal wetlands conservation, the imperfect legal and management system for coastal wetlands, and the insufficient education, research and international cooperation. Although the threats and pressures on coastal wetlands conservation are still apparent, the future of China's coastal wetlands looks promising since the Chinese government understands that the sustainable development in coastal zone requires new attitudes, sound policies and concerted efforts at all levels. The major strategies for future improvement of China's coastal wetland conservation include: exploring effective measures in response to major threaten factors; improving the conservation and compensation system for coastal wetlands; strengthening coastal wetland legislation and management; increasing funds for coastal wetland conservation and research; and Strengthening coastal wetland education and international cooperation. (C) 2015 Elsevier Ltd. All rights reserved

    CHINA'S WETLANDS CONSERVATION: ACHIEVEMENTS IN THE ELEVENTH 5-YEAR PLAN (2006-2010) AND CHALLENGES IN THE TWELFTH 5-YEAR PLAN (2011-2015)

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    China's natural wetlands occupy 3.77% of the land and provide 54.9% of China's ecosystem services. Healthy natural wetland ecosystems play an important role in the sustainable development of China, which was realized by the Chinese government in the early 1970s. In the past 5 years, China has made great efforts in wetlands conservation, which is signified by the funding of billions of dollars to restore degraded wetlands, the policy to return reclaimed croplands to wetlands, the specific regulation to strengthen wetlands management, the coordination mechanism to enhance management capacity, and the communication to strengthen international cooperation. This paper introduces the background of China's wetlands, compares the status of wetlands conservation globally and in China, illustrates the achievements, policies and measures of China's wetlands conservation during the Eleventh 5-Year Plan (2006-2010), analyzes the issues existing in current wetlands conservation, and discusses the challenges, efforts and measures in protecting natural wetlands in the Twelfth 5-Year Plan (2011-2015). The future of China's wetlands looks promising since China has already realized that wetlands conservation is a national imperative to guarantee the sustainable development of economy and society.China's natural wetlands occupy 3.77% of the land and provide 54.9% of China's ecosystem services. Healthy natural wetland ecosystems play an important role in the sustainable development of China, which was realized by the Chinese government in the early 1970s. In the past 5 years, China has made great efforts in wetlands conservation, which is signified by the funding of billions of dollars to restore degraded wetlands, the policy to return reclaimed croplands to wetlands, the specific regulation to strengthen wetlands management, the coordination mechanism to enhance management capacity, and the communication to strengthen international cooperation. This paper introduces the background of China's wetlands, compares the status of wetlands conservation globally and in China, illustrates the achievements, policies and measures of China's wetlands conservation during the Eleventh 5-Year Plan (2006-2010), analyzes the issues existing in current wetlands conservation, and discusses the challenges, efforts and measures in protecting natural wetlands in the Twelfth 5-Year Plan (2011-2015). The future of China's wetlands looks promising since China has already realized that wetlands conservation is a national imperative to guarantee the sustainable development of economy and society

    Spatial variations and bioaccumulation of heavy metals in intertidal zone of the Yellow River estuary, China

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    Nine units in new-born intertidal zone of the Yellow River estuary, China were examined for concentrations of heavy metals (Pb, Cr, Cu, Zn and Ni) in sediments and plants. Heavy metal levels in surface sediments were in the order of Zn > Pb approximate to Cr > Cu approximate to Ni and generally increased in a seaward direction except for Z6 (Tamarix chinensis-Suaeda salsa zone) and Z7 (S. salsa-T. chinensis zone) units. Significant differences in metal concentrations of the 9 units were observed in the profiles (p < 0.01). Heavy metal levels in the shoots or roots of different plants decreased in the order of Zn > Cu > Pb > Ni > Cr and differed among plants or tissues. The roots at Z2 (Calamagrostis pseudophragmites zone), Z3 (Imperata cylindrical zone) and Z4 (Phramites australis zone) units accumulated greater metals than shoots [TFs (translocation factors) < 1], while the shoots at Z1 (Sparganium minimum-Potentilla supina zone), Z7 and Z8 (S. salsa zone) units accumulated greater metals than roots (TFs > 1), implying that intertidal plants showed different pathways in metal accumulation and internal transportation. Except for Pb, the concentrations of Cr, Cu, Zn and Ni in sediments were lower than the criteria of Class I recommended by the Environmental Quality Standard for Soils of China, Although heavy metal levels in intertidal zone were generally the lowest (Cr, Cu, Zn and Ni) or relatively moderate (Pb) compared with other estuaries or bays in Asia and Europe, high eco-toxic risk of Pb and Ni exposure still could be observed at Z4, Z6 and Z9 (mudflat zone) units. S. salsa was more suitable for the potential biomonitor or phytoremediation of all five heavy metals if intertidal sediments was seriously contaminated with increasing of pollutants loading in the Yellow River estuary. (C) 2014 Elsevier B.V. All rights reserved
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