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首页> 外文期刊>Holzforschung >The states of water in Norway spruce (Picea abies (L.) Karst.) studied by low-field nuclear magnetic resonance (LFNMR) relaxometry: assignment of free-water populations based on quantitative wood anatomy
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The states of water in Norway spruce (Picea abies (L.) Karst.) studied by low-field nuclear magnetic resonance (LFNMR) relaxometry: assignment of free-water populations based on quantitative wood anatomy

机译：低场核磁共振弛豫法研究挪威云杉（Picea abies（L.）Karst。）的水状态：基于定量木材解剖的自由水种群分配

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摘要

Low-field nuclear magnetic resonance (LFNMR) relaxometry was applied to determine the spin-spin relaxation time (T-2) of water-saturated Norway spruce (Picea abies (L.) Karst.) specimens cut from mature sapwood (sW) and mature and juvenile heartwood (hW), where earlywood (EW) and latewood (LW) were separated. In combination with quantitative wood anatomy data focusing on the void volumes in various morphological regions, the NMR data served for a more reliable assignment of free-water populations found in water-saturated solid wood. Two free-water populations were identified within most sample types. One was assigned to water in the tracheid lumen and the other to water inside bordered pits. Whether water in the ray cell lumina was included in one or the other of these two populations depends on the curve-fit method applied (continuous or discrete). In addition, T-2 differences between the different tissue types were studied and, for comparison, sorption isotherms were measured by means of a sorption balance. There was a significant difference between EW and LW as well as between juvenile wood and mature wood in terms of T-2 related to the cell wall water. However, no differences were seen between the sorption isotherms, which indicates that the observed T-2 differences were not due to differences in cell wall moisture content (MC).
机译：应用低场核磁共振（LFNMR）弛豫测定法确定从成熟边材（sW）和木屑切下的水饱和挪威云杉（Picea abies（L.）Karst。）标本的自旋自旋弛豫时间（T-2）。成熟和少年心材（hW），其中早材（EW）和晚材（LW）是分开的。结合专注于各种形态区域中空隙体积的定量木材解剖学数据，NMR数据可更可靠地分配水饱和实木中发现的自由水种群。在大多数样本类型中确定了两个自由水种群。一个被分配给水管腔内的水，另一个被分配给有边界的坑内的水。这两个总体中的一个或另一个中是否包含射线单元腔中的水，取决于所采用的曲线拟合方法（连续或离散）。另外，研究了不同组织类型之间的T-2差异，并且为了进行比较，通过吸附平衡测量了吸附等温线。就细胞壁水相关的T-2而言，EW和LW之间以及幼木和成熟木之间都存在显着差异。但是，在吸附等温线之间没有发现差异，这表明观察到的T-2差异不是由于细胞壁水分含量（MC）的差异。

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