中文摘要：

【目的】对不同株型小麦冠层叶片垂直分布的方向光谱响应进行研究，探索精确描述小麦冠层空间信息的途径，为农田作物快速、无损的光谱监测提供新的理论与技术。【方法】以2个株型不同的小麦品种为材料，采用自下向上分层切片方法，分析冠层不同部位叶片对冠层方向光谱的影响。【结果】去除不同叶位叶片后，小麦冠层光谱在300-700，800-1300，1400-1800nm波段差别明显；不同观测角度中，与传统90°视角获得反射信息比较，30°和60°视角反射光谱包含较多下部叶片信息，下部叶片对冠层光谱反射率贡献较大，0°视角反射光谱包含较多上部叶片信息，上部叶片对冠层光谱反射率贡献较大；小麦冠层的穗层和倒1叶对方向光谱产生很大影响。不同的2个小麦品种，ZY9844上部叶片对反射率的影响比P7弱。【结论】小麦冠层不同部位叶片，对冠层方向光谱影响不同，根据冠层特点，通过改变光谱观测角度，可以提高作物冠层光谱监测的精度。

英文摘要：

[Objecive] The direction spectrum response of the wheat vertical leaf distributing were research, explored the method of accurate description wheat canopy spatial information, aimed to provide a valuable aid to repidly, harmless spectral estimates on crop. [ Method ] This experiment was conducted with two winter-wheat （Triticum aestivum） cultivars P7 （leaf erect） and ZY9844 （leaf horizontal）. The wheat canopy direction spectral reflectance over 350-2500nm with view angles of 0°, 30°, 60°, 90°, 120°, 150°and 180° to the vertical line of wheat row were measured, using delamination slice method from underlayer of the wheat canopy to upside at milking stage, and the direction spectral characteristics of removing different leaf layers were compared. [Result] The contributions of different layers to Canopy Direction Spectra （CDS） were preliminarily defined, which were obviously different at 300-700 nm, 800-1 300 nm and 1 400-1 800 nm. Compared with the traditional 90° observational angle, the spectral information observed at the 0° angle mainly revealed the information of upper canopy and the lower layer had little impact on their spectra. However, the spectral information observed at 30° and 60° angles reflected the whole canopy information and the status of the lower layer of canopy had great effect on their spectra. Variance analysis indicated that ear layer of canopy and the first top leaf blade made greater contributions to CDS. The reflectance spectra of upper leaves of ZY9844 had less impact than that of P7.[ Conclusion ] The canopy spectral information is affected by the observation angles. To improve crop canopy spectral estimation precision, it is better to change the measured angle for different canopy structures.