黄土丘陵区油松和沙棘人工林的水分来源变化及其生理响应研究

项目名称： 黄土丘陵区油松和沙棘人工林的水分来源变化及其生理响应研究

项目编号： No.41501576

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 地质学

项目作者： 唐亚坤

作者单位： 中国科学院水利部水土保持研究所

项目金额： 22万元

中文摘要： 人工林占黄土丘陵区森林面积的59.8%，其中70.4%的人工林易受季节性干旱的影响。人工林水分利用的稳定性是评价该地区水土流失治理和生态恢复可持续性的重要指标，且需要通过植物水分来源的变化和植物的生理响应进行判断。本项目拟以黄土丘陵区安塞国家生态试验站旺盛生长时期的油松、沙棘人工纯林和油松-沙棘混交林为研究对象，以稳定同位素红外光谱技术为基础，开展植物茎秆水、土壤水、降水和地下水氢氧稳定同位素的连续采样与分析，结合MixSIR模型量化油松和沙棘的水分来源，阐明混交造林对油松和沙棘水分来源的影响。同时，对油松和沙棘的气孔导度、叶片光合速率以及叶片水势进行观测，并结合该地区季节性干旱和降水事件，探讨改变油松和沙棘水分来源及其生理响应的水分环境条件，进而揭示油松、沙棘人工纯林和油松-沙棘混交林的水分利用策略，为黄土丘陵区生态恢复过程中人工林水分利用稳定性的评估和可持续性管理提供科学依据。

中文关键词： 氢氧稳定同位素；油松；沙棘；水分来源量化；生理响应

英文摘要： Plantation forests account for 59.8% of forested area in Loess Plateau hilly region, and approximately 70.4% of plantation forests are vulnerable to seasonal drought stress. The water use stability of plantation forest is essential to assess the sustainability of soil and water conservation and ecological recovery in this region, which can be evaluated from both water sources variation and physiological response of plantation species. This study mainly focuses on Pinus tabulaeformis, Hippophae rhammoides and P. tabulaeformis-H. rhammoides plantations during vigorous growth period in Ansai National Ecological Experimental Station in Loess Plateau hilly region. Based on isotopic ratio infrared spectroscopy systems, stable hydrogen and oxygen isotopes of water in plant xylem, soil, precipitation and groundwater for P. tabulaeformis and H. rhammoides in these plantations can be analyzed. Then, the fractions of water sources for P. tabulaeformis and H. rhammoides can be quantified through a MixSIR model. The mixed plantation effect to water sources for these two forest species can also be evaluated. Meanwhile, physiological response for P. tabulaeformis and H. rhammoides can be analyzed through stomatal conductance, leaf photosynthesis rate and leaf water potential observation. Then, combined with drought stress and precipitation events, water conditions that may alter plant water sources variation and physiological response can be investigated. The water use strategies for P. tabulaeformis, H. rhammoides and P. tabulaeformis-H. rhammoides plantations can be revealed based on plant water sources variation and physiological response analysis. In further, it would be useful to provide scientific basis for evaluate the water use stability and sustainability management of plantations in terms of ecological recovery in this region.

英文关键词： Stable hydrogen and oxygen isotopes;Pinus tabulaeformis;Hippophae rhammoides;Water sources quantification;Physiological response