基于Fraunhofer线的小麦条锈病荧光遥感探测

【目的】遥感监测小麦条锈病比传统调查方法更省时、省力并能实现大范围实时监测。【方法】田间人工诱发产生不同发病等级的小麦条锈病群体，采用ASD光谱仪的Radiance方式对其冠层光谱进行了测定。通过比较目标和参考板太阳光谱中两个氧吸收波段的Fraunhofer线深，计算植株发射的叶绿素荧光。【结果】760 nm处叶绿素荧光与病情指数高度负相关，688 nm处叶绿素荧光与病情指数高度正相关。并且随着病情指数的升高，作为反映植物胁迫状态的荧光比值指标F688/F760亦随之增大。另外对单叶相关光合指标测试结果表明，随着病叶严重度水平的升高，SPAD、荧光参数Fv/Fm和Yield以及净光合速率均有不同程度的下降。【结论】利用Fraunhofer线原理提取的日光诱导荧光信息可以反映田间小麦条锈病的发病状况，为病害的遥感监测提供了又一途径。

Chlorophyll Fluorescence Sensing to Detect Stripe Rust in Wheat (Triticum aestivum L.) Fields Based on Fraunhofer Lines

Wheat stripe rust detection based on chlorophyll fluorescence (CF) sensing is large area and real time, with more advantages of saving time and labor compared to traditional investigation. Diseases with different levels were induced by artificial inoculation, and then canopy radiances were measured using the ASD field spectrometer. The amount of CF was quantified at 688 nm and 761 nm, where the solar spectrum was attenuated (Fraunhofer lines). The results showed that CF at 688 nm was positively correlated with the disease index (DI) whereas CF at 761 nm was negatively correlated with DI. Ratios of CF at 688 to that at 761 nm, which found to be a suitable indicator of stress events in plants, were positively related to DI. Besides, measurements of several photosynthetic parameters (SPAD, Fv/Fm, Yield and Pn) have been shown to decrease as leaf sev