基于倾斜遥感观测的小麦白粉病胁迫下叶绿素含量监测

为了探讨多角度遥感在白粉病胁迫下监测小麦叶绿素含量的适宜角度,以易感白粉病品种偃展4110和中感白粉病品种国麦301为试验材料,获取三种不同生长环境(病圃田、接种田和自然感病田)下抽穗至灌浆期小麦冠层多角度反射光谱及叶绿素含量,分析不同时期叶绿素含量变化及其与多角度反射率的关系,建立白粉病胁迫下小麦叶绿素含量监测模型。结果表明,由红边波段构建的光谱参数对白粉病胁迫下叶绿素含量变化反应敏感。优化筛选出的植被指数与叶绿素含量之间的相关性在前向角度观测时优于垂直角度观测,而垂直观测角度好于后向角度观测,整体上以前向20°最佳。植被指数中,光谱参数RES(红边对称度)表现较好,在前向20°下的监测精度达0.725。因此,在前向20℃观察条件下可用RES对白粉病危害后小麦冠层叶绿素含量变化进行有效监测。

Remote Estimation of Chlorophyll Content under Stress of Powdery Mildew Using Inclination Observation Method in Wheat

In order to clarify the possibility of applying remote sensing to determine chlorophyll content in wheat under powdery mildew stress,we mainly studiedon the variable relations between Chl(a+b) in wheat leaves and canopy reflectance based on multiple views of hyperspectral remote sensing,with two wheat cultivars(a susceptible variety Yanzhan 4110 and a moderately susceptible variety Guomai 301) as materials under three different growing conditions.The changes of chlorophyll content at different stages and the relationship between chlorophyll content and multi-angle reflectance were analyzed. A monitoring model of chlorophyll content in wheat under powdery mildew stress was established. The results showed that the spectral parameters constructed from red-edge band were sensitive to the changes of chlorophyll content under powdery mildew stress. The correlation between the optimized vegetation index and chlorophyll content was better in the forward observation angle than that in the vertical observation angle,while the vertical observation angle was better in the backward observation direction,and the former 20 degree was the best. Compared with other vegetation indices,the spectral parameter RES(red edge symmetry) performs better,and the monitoring accuracy in the forward 20 degree reaches to 0.725. Therefore,RES can be used to effectively monitor the changes of chlorophyll content in wheat canopy under powdery mildew stress.