论文部分内容阅读
植物-水分关系是生态水文过程的重要环节,稳定同位素技术的应用极大地扩充了该领域的研究范围,提高了研究精度。但因植物样品的水分抽提费时费力,限制了该技术的应用。本研究以植物茎水抽提为例,采用低温真空蒸馏法,通过分析相同质量不同植物样品在同一时间梯度下水分提取率及基于同位素值的水分抽提时间曲线的变化特征,揭示不同植物茎水的最短抽提时间,并建立最短抽提时间与植物木材密度的相关关系。结果表明,目标植物盐肤木、红背山麻杆和火棘的木材密度分别为0.35、0.55和0.67 g·cm-3;质量基本相同(约3 g)的3种植物样品的水分提取率在45 min左右均接近100%;由于水分收集的滞后性,基于同位素值的最短抽提时间分别为不小于45、60和60 min,并随木材密度增大而延长。研究结果指示着建立木材密度与植物茎水最短抽提时间曲线的可能,能有效提高抽提效率。
The relationship between plant and water is an important part of the eco-hydrological process. The application of stable isotope technology greatly expands the research scope in this field and raises the research precision. However, the time-consuming and labor-intensive extraction of water from plant samples has limited the application of this technology. In this study, the plant stem water extraction as an example, the use of low-temperature vacuum distillation method, by analyzing the same quality of different plant samples at the same time under the gradient of water extraction rate and isotope-based water extraction time curve of the characteristics of variation reveals different plant stems The shortest extraction time of water, and establish the correlation between the shortest extraction time and plant wood density. The results showed that the wood densities of the target plants Rhizoma Paridis, Rhodiola sachalinensis and Pyracantha were 0.35, 0.55 and 0.67 g · cm-3, respectively. The water extract rates of the three plant samples with the same quality (about 3 g) 45 min or so are close to 100%; due to the lag of water collection, the shortest extraction time based on isotope values are not less than 45,60 and 60 min, respectively, and lengthen with the increase of wood density. The results indicate that it is possible to establish the curve of the shortest extraction time of wood density and plant stem water, which can effectively improve the extraction efficiency.