Simultaneous Preservation of Soil Structural Properties and Phospholipid Profiles: A Comparison of T

来源 :Pedosphere | 被引量 : 0次 | 上传用户:sina
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
There is a need to simultaneously preserve evidence of interactions between the biological community and soil struc- tural properties of a soil in as near an intact(natural)state as possible.Three dehydration techniques were implemented and assessed for their ability to minimise disruption of both biological and physical properties of the same arable soil sample.Dehydration techniques applied until samples were at constant weight were i)air-drying at 20°C(AD);ii) -80°C freeze for 24 h,followed by freeze-drying(-80FD);and iii)liquid nitrogen snap freeze,followed by freeze-drying (LNFD)and were compared to a moist control.Physical structure was determined and quantified in three dimensions using X-ray computed tomography and microbial phenotypic community composition was assessed using phospholipid fatty acid(PLFA)profiling.This study confirms that any form of dehydration,when preparing soil for simultaneous biological and physical analysis,will alter the soil physical properties,and cause some change in apparent community structure.Freeze-drying(both the LNFD and-80FD treatments)was found to minimise disruption(when compared to the moist control soil)to both the soil physical properties and the community structure and is a preferable technique to air-drying which markedly alters the size and character of the pore network,as well as the phenotypic profile.The LNFD was the preferred treatment over the-80FD treatment as samples show low variability between replicates and a fast turn-around time between samples.Therefore snap freezing in liquid nitrogen,followed by freeze drying is the most appropriate form of dehydration when two sets of data,both physical and biological,need to be preserved simultaneously from a soil core. There is a need to simultaneously preserve evidence of interactions between the biological community and soil struc- tural properties of a soil in as near an intact (natural) state as possible. Thhree dehydration techniques were implemented and assessed for their ability to minimize disruption of both biological and physical properties of the same arable soil sample. Dehydration techniques applied to samples were at constant weight were i) air-drying at 20 ° C (AD); ii) freeze-24 h at -80 ° C, followed by freeze- drying (-80FD); and iii) liquid nitrogen snap freeze, followed by freeze-drying (LNFD) and were compared to a moist control. Physical structure was determined and quantified in three dimensions using X-ray computed tomography and microbial phenotypic community composition was assessed using phospholipid fatty acid (PLFA) profiling. This study confirms that any form of dehydration, when preparing soil for simultaneous biological and physical analysis, will alter the soil physical properties, and c ause some change in apparent community structure. Freeze-drying (both the LNFD and-80FD treatments) was found to minimize disruption (when compared to the moist control soil) to both the soil physical properties and the community structure and is a preferable technique to air-drying which markedly alters the size and character of the pore network, as well as the phenotypic profile. LNFD was the preferred treatment over the-80 FD treatment as samples show low variability between replicates and a fast turn-around time between samples. Thus snap freezing in liquid nitrogen, followed by freeze drying is the most appropriate form of dehydration when two sets of data, both physical and biological, need to be preserved simultaneously from a soil core.
其他文献
本文共分前言、正文和结论三部分。前言部分,概括介绍了中止犯的本质及中止犯成立条件研究的必要性,阐明了本文论述的理论价值和写作目的。正文共分为五章:第一章是关于中止犯的
商标淡化理论不同于传统的商标侵权理论即混淆理论,它通过给予驰名商标以跨类保护从而扩大了对驰名商标权利人的权利保护范围。然而,商标是商标权人与消费公众共同创造的结果
健全高校学生校内申诉制度,对维护高校学生合法权益以及推行依法治校具有重要意义,目前我国关于高校学生校内申诉制度的研究并不全面,以法学视角研究的更少,主要集中在高校学
党的十六大报告指出,要“形成全民学习、终身学习的学习型社会,促进人的全面发展”。这是我们党顺应时代发展的趋势和要求,全力提高国民素质,实现民族兴旺发达的重大举措。但是,构
改革开放三十多年来,中国发生了翻天覆地的变化。经济持续高速发展,民主法治不断健全,人民生活水平稳步提高,逐步建立起适应中国国情的中国特色社会主义制度。回首三十多年前
秋季大棚黄瓜延晚栽培,是在秋季冷凉季节进行,利用大棚保温作用继续生产黄瓜的生产方式。该茬黄瓜生长前期处于高温季节,而生长后期温度急剧下降,环境条件差异较大,在栽培管
在焊接过程中,焊接应力以及变形大多是不可避免的.它们对焊接结构的尺寸精度有着直接的影响,对焊接接头的强度有着直接的影响,需要付出很多的人力、 物力对其进行矫正,甚至还
随着全球经济社会不断发展变化,世界政治经济格局也从1-2元结构转向多元化,中国在其间的主要位置也越来越突出,西方有头脑的政治家也指出“21世纪是中国的世纪”。在新时期新
近年来,广西各级纪检监察机关深入贯彻落实科学发展观,坚持标本兼治、综合治理、惩防并举、注重预防的方针,严格执行党风廉政建设责任制,认真落实《建立健全惩治和预防腐败体