中文摘要：

利用叶片反射光谱实时、无损地探测植物水分状况是森林干旱评估的新方法,但是不同光谱指数的水分敏感性存在很大差异,因此,确定适用于树木叶片的水分指标与其敏感的光谱指标均非常重要。该研究选取锐齿槲栎（Quercus aliena var.acuteserrata）不同发育阶段和冠层位置上的叶片作为研究对象,在失水条件下,测定叶片的水分指标及其同步的反射光谱响应曲线,探究叶片的光谱反射率变化与水分状况改变的关系,比较并评估不同叶片发育阶段和冠层位置叶片的水分指标与不同反射光谱指数之间相关关系的优劣。结果表明：（1）在4个不同水分指标中,与比叶含水量（SWC）和叶片水分鲜质量比（LMP）相比,相对含水量（RWC）和等效水分厚度（EWT）在不同发育阶段和冠层位置之间的变异性更小,能稳定地表征树木整体的水分状况;且RWC和EWT具有更高的光谱敏感性,适用于遥感探测。（2）光谱反射率差值分析法和光谱反射率敏感性分析法表明：叶片的光谱敏感性受发育阶段的影响较大;在短波红外区域,成熟叶片在失水胁迫初始阶段的光谱变化较小,而新展叶在整个失水阶段均表现出明显的光谱差异。（3）通过对15个不同光谱指数与水分指标的相关分析,发现水分指数（WI）-RWC和双差值指数（DDn（1530,525））-EWT均具有较高的相关性,其中,WI-RWC的拟合关系受叶片发育阶段和冠层位置的影响较大;而DDn（1530,525）-EWT的拟合关系更为稳定。

英文摘要：

Aims Using leaf spectral reflectance to detect plant status in real time and non-destructively is a new method of forest drought assessment, but each spectral index possesses considerable moisture sensitivity. Therefore, determining moisture index applicable to tree leaf and its sensitive spectral index are both very important. Methods This study selected Quercus aliena var. acuteserrata leaves in different growth stages and canopy positions as the research object, and measured leaf moisture index and its synchronous reflectance spectral response curve during the dehydration process, explored the relationship between changes of leaf spectral reflectance and water status, compared and evaluated the advantages and disadvantages of correlation between the moisture indices of leaves in different growth stages and space positions and different spectral reflectance indices. Important findings Results indicated：（1） The variability of relative water content（RWC） and equivalent water thickness（EWT） in different growth stages and canopy positions was smaller than specific leaf water content（SWC） and leaf moisture percentage on fresh quality（LMP） as measured by the four different moisture indices. RWC and EWT could steadily characterize the holistic water status of trees, and they had greater spectral sensitivity. Therefore, they were suitable for application in remote sensing detection.（2） Spectral reflectance difference analysis and spectral reflectance sensitivity analysis showed that the leaf spectral sensitivity is strongly influenced by growth stage. In short wave infrared region, spectral reflectance of mature leaves changed slightly in the initial stage of dehydration stress, but new expended leaves showed obvious spectral differences during the dehydration process.（3） Through the correlation analysis between 15 different spectral indices and moisture indices, we found that water index（WI）-RWC and double difference index（DD_（n（1530,525）））-EWT has higher correlation. The