水稻白叶枯病荧光遥感监测方法

The monitor of crop diseases using remote sensing methods were mostly focused on either single leave or canopy scale, few studies were found on the combine of single leave and canopy remote sensing. Remote sensing crop diseases using the combine of two methods (reflectance and chlorophyll fluorescence) were also no reported. Two scales (single leave and canopy) and two methods (reflectance and chlorophyll fluorescence) maybe have the better monitoring effect. This study will artificially induce bacterial blight of rice based on our previous study. The effect of disease on reflectance (reflectance and spectral indices) and chlorophyll fluorescence (dark and light adaptation chlorophyll fluorescence) will be analyzed, and the relation of disease index and reflectance and chlorophyll fluorescence parameters will be investigated from the leaf and the canopy. Model based the combine of s reflectance and chlorophyll fluorescence will be built and discussed. Our work was hoped to clarify the internal driving mechanism of remote monitoring crop diseases in theory, and provide a new, timely, effective and remote detection of crop disease in application.

目前作物病害的遥感监测研究多集中在单叶或冠层方面，通过两种尺度相结合的作物病害遥感监测研究少见报道；此外当前国内外通过反射光谱结合叶绿素荧光进行作物病害遥感监测的研究也不多见。两种尺度（单叶、冠层）与两种遥感方法（光谱、叶绿素荧光）相结合的作物病害遥感监测研究可能比单一尺度或单一方法更具有监测精度或监测效果优势。本项目在前期相关研究基础上，拟以水稻为试验材料，通过人工诱发产生不同严重程度白叶枯病害，在考察病害对水稻反射光谱（光谱反射率及光谱指数）与叶绿素荧光参数（暗适应与光适应荧光）影响的基础上，从单叶与冠层两个层面分析水稻荧光遥感信息与病情指数的相关关系，构建基于光谱特征与叶绿素荧光相结合的水稻白叶枯病害荧光遥感监测的技术方法。本研究在理论上可以阐明利用荧光遥感信息探测作物生长发育进程变化的内在驱动机制，在实践上也可为实际的农业生产提供及时、准确、有效的作物病害遥感监测方法。

水稻感染白叶枯病后，叶绿素含量（SPAD）降低，MDA（丙二醛）含量、SOD（超氧歧化物酶）增加，表明感病后水稻叶细胞及光合机构遭到破坏，直接导致了不同病害严重程度下水稻光合速率、反射光谱及叶绿素荧光的差异，这也是水稻白叶枯病荧光遥感监测的内在生理原因。感染白叶枯病后，水稻光合速率、光饱和速率、表观量子效率、CO2饱和速率、可见光-近红外光谱反射率呈显著降低趋势，叶绿素荧光参数最小荧光F0、最大荧光Fm、PSII原初光能转化效率Fv/Fm、电子传输速率ETR、实际荧光产量ΦPSII降低，这是水稻白叶枯病荧光遥感监测的参数基础。筛选了水稻光谱、荧光等不同特征参数，表明通过SPAD、反射光谱、叶绿素荧光参数等遥感方法可以监测水稻不同病害严重程度的白叶枯病害。相对而言，反射光谱、SPAD对水稻白叶枯病的监测精度优于叶绿素荧光。构建基于SPAD、RNIR（近红外处的光谱反射率）的白叶枯病情指数反演模型，经独立田间试验验证后模型估算准确率在83.2%、86.4%，可以用于实际田间的水稻白叶枯病遥感监测。