Variations in Growth,Clonal and Sexual Reproduction of Spartina alterniflora Responding to Changes in Clonal Integration and Sand Burial   总被引：1，自引：0，他引：1       下载免费PDF全文

Yan Xiao  Hui Zhao  Wen Yang  Hua Qing  Changfang Zhou  Junbing Tang  Shuqing An 《洁净——土壤、空气、水》2015,43(7):1100-1106

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The Invasion of Spartina alterniflora Alters Carbon Dynamics in China's Yancheng Natural Reserve          下载免费PDF全文

Changfang Zhou  Hui Zhao  Zhiyi Sun  Luxian Zhou  Chao Fang  Yan Xiao  Zifa Deng  Yingbiao Zhi  Yongqiang Zhao  Shuqing An 《洁净——土壤、空气、水》2015,43(2):159-165

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生物结皮中优势蓝藻胞外多糖对几种荒漠草本植物种子萌发的影响   总被引：2，自引：0，他引：2  

龚健  张丙昌  索菲娅 《中国沙漠》2015,35(3):639-644

蓝藻是荒漠生物结皮的重要组成。选取生物结皮中的优势蓝藻(具鞘微鞘藻(Microcoleus vaginatus)、眼点伪枝藻(Scytonema ocellatum)、地木耳(Nostoc commune)),通过提取其胞外多糖,研究了不同蓝藻胞外多糖对荒漠植物种子萌发的影响。结果表明:具鞘微鞘藻、眼点伪枝藻的胞外多糖对粗枝猪毛菜(Salsola subcrassa)的种子萌发表现为低浓度抑制、高浓度促进作用,地木耳的胞外多糖仅在高浓度时对粗枝猪毛菜的种子萌发具有促进作用(p<0.05);具鞘微鞘藻胞外多糖对小花荆芥(Nepeta micrantha)种子萌发无明显的影响作用,但眼点伪枝藻和地木耳对小花荆芥种子萌发具有抑制作用。具鞘微鞘藻、眼点伪枝藻和地木耳胞外多糖对琉苞菊(Hyalea pulchella)种子萌发具有明显的抑制作用。藻种胞外多糖组分的差异和不同种子的生物学特性差异可能是造成不同藻种胞外多糖对种子萌发产生不同影响的主要原因。  相似文献   

Instant luminescence chronologies? High resolution luminescence profiles using a portable luminescence reader     

《Quaternary Geochronology》2015

Establishing a robust chronology is fundamental to most palaeoenvironmental studies. However, the number and positioning of dated points is critical. Using a portable luminescence reader, it is possible to rapidly generate high resolution down core relative age profiles. Profiles of portable luminescence data from two coastal dunes were evaluated and compared with the results of particle size analysis, stratigraphy, and an independent historical chronology. Results show that, even in young samples, portable luminescence data is dominated by an age related signal which in homogeneous sediment need not be corrected for moisture, feldspar content changes or grain size. Profiles therefore provide relative chronologies from which accumulation phases can be established, and from which better targeted sampling and comparison to other sites could be undertaken. Even though they do not provide instant absolute chronologies, field-based portable luminescence profiling of Late Quaternary sites hold much potential to improve the resultant chronologies.  相似文献   

OSL dating of fine and coarse quartz from a Palaeolithic sequence on the Bistrița Valley (Northeastern Romania)     

《Quaternary Geochronology》2015

Previous works focused on optically stimulated luminescence dating of quartz extracted from Romanian and Serbian loess reported significant discrepancies between ages obtained on fine (4–11 μm) and coarse (63–90 μm) quartz. The present study is directed at expanding these investigations. The SAR-OSL and double SAR-OSL protocols are applied on quartz of different grain sizes belonging to 9 samples extracted from a newly identified archaeological site at Bistricioara-Lutărie III on the Bistrița Valley (NE Romania). Radiocarbon ages are also obtained for the 3 uppermost cultural layers hosted in the loess-like deposit.Discrepant ages are obtained between fine (4–11 μm) and coarse (63–90 and 90–200 μm, respectively) quartz for equivalent doses higher than ∼80–100 Gy. However, a very good agreement is achieved for the youngest sample, with an age of ∼8 ka (with a D_e of 38 Gy for fine and 35 Gy for coarse grains, respectively). The comparison with independent control provided by radiocarbon dating suggests better agreement of ages calculated for coarse quartz. Our results are once again proof that concerns should be raised regarding the reliability of the equivalent doses obtained on quartz samples for which the laboratory dose response cannot be fitted by a single saturating exponential function. Further systematic investigations are required regarding the very different saturation characteristics of fine and coarse grained quartz.  相似文献   

从秦岭蕨类植物区系地理成分论秦岭山地生态分界线的划分   总被引：6，自引：0，他引：6  

王菁兰  刘全儒  孟世勇  赵鸣飞  康慕谊 《地理研究》2010,29(9):1629-1638

依据2007~2008年野外实地调查以及相关文献资料,运用植物区系地理学和数量生态学方法,分析了秦岭蕨类植物区系的物种组成和地理分布特征,划分了秦岭蕨类植物的垂直带谱,并以此为基础探讨了秦岭山地生态分界线的划分,得出以下主要结论:(1)秦岭共有蕨类植物36科85属311种,优势科为鳞毛蕨科、蹄盖蕨科和水龙骨科,优势属为鳞毛蕨属和耳蕨属;在科属水平上,以热带成分占优势;而种的水平则以温带成分占绝对优势。(2)根据秦岭蕨类植物南北坡垂直带谱的对比分析,南坡海拔1000m左右应该是一条重要的生态分界线。(3)南坡1000m以下蕨类植物区系组成更接近亚热带区系,而其他地带则与温带蕨类植物区系更为接近,DCA排序很好地证明了此结果。综合来看,将南坡海拔1000m作为秦岭山地亚热带与暖温带的生态分界线较为科学。  相似文献   

Establishing a Clean‐quality Indicator System for Evaluating Reclaimed Land in the Antaibao Opencast Mine Area,China     

R. T. Bi  Z. K. Bai  H. Li  H. B. Shao  W. X. Li  B. Y. Ye 《洁净——土壤、空气、水》2010,38(8):719-725

This article discusses the existing problems associated with reclaimed land in the area of the Antaibao Opencast Coal Mine, which is located in the semi‐arid region of northwest China. The following eight indicators of the suitability of the reclaimed land were developed based on the theory of soil genesis and landscape ecology: the thickness of the effective soil layer, composition of the soil surface, vegetation index, types of covering vegetation, slope of the terrain, time of reclamation, area of the evaluation unit, and the shape index of the evaluation unit. The suitability evaluation indexes of the reclaimed land were determined using the 3S technology and fuzzy evaluation methods, which revealed that the suitability of the reclaimed land in the study area could be divided into six grades and two categories, land suitable for farming, and land suitable for trees or grass. The suitability evaluation indicators and evaluation methods developed to evaluate reclaimed land in this study will be beneficial to the large‐scale rapid monitoring and the effective management of reclaimed land in the opencast mine area.  相似文献   

离子注入对农杆菌介导将大豆球蛋白基因转入杨柴愈伤组织的影响     

陈玲玲  那日  邢万金  刘美玲 《中国沙漠》2010,30(5):1104-1107

以杨柴愈伤组织为材料,研究了低能离子束注入对农杆菌介导将11S大豆球蛋白基因Gy3(A1aB1b)转入杨柴愈伤组织的影响。杨柴愈伤组织经离子束注入处理后以根癌农杆菌侵染,通过GUS报告基因表达的组织化学染色分析和PCR检测,发现离子注入显著增强了根癌农杆菌对愈伤组织的侵染转化效率,初步证明大豆基因已整合到杨柴基因组中。  相似文献   

黔西南岩溶区饲料灌木营养元素分析     

黄芬  曹建华  丁俊峰  韦红群  高喜 《热带地理》2010,30(3)

对生长在黔西南州岩溶区的27种饲料灌木常规营养成分及元素作测定,对结果进行灰色关联度及相关性分析,结果表明:构树所含营养元素综合评价为最好,以下依次为青刺尖牛王刺光腺合欢马棘小构树火棘白刺花紫穗槐刺梨。碳、氮、钙元素与饲料常规营养成分相关性最大,其次为钾、磷、硒、铁、锌,其多数与饲料的粗蛋白、粗脂肪、灰分呈正相关,与粗饲料的粗纤维呈负相关。  相似文献   

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs     

《Chemie der Erde / Geochemistry》2002

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.  相似文献