Development of hyper-spectral imaging system for diagnosis of growth and photosynthetic reactions

在本研究中，开发了用于生长和光合作用诊断的高光谱成像系统。利用该系统测量的550 nm和900 nm波段比，估算了不同施肥条件下大田小麦植株的生长和叶绿素含量。同时，荧光光谱法可以无损、远程获取植物叶片的色素、细胞结构、生理功能等信息。利用三维荧光分光光度计测定了水分胁迫菠菜叶片在黑暗环境下的激发-发射基质，并分析了这些基质随时间的变化。F450/F680和F450/F725在短波长紫外线（如330nm）激发下适用于检测菠菜叶片相对含水量的变化。利用研制的叶绿素荧光成像系统，分析了一种市售土施型尿素除草剂对黄瓜叶片的光合效应。通过CFI法拍摄的Chl荧光诱导（CFI）图像（暗光转换过程中Chl荧光强度的变化）检测损伤部位初级电子传递的抑制作用。根据饱和脉冲法拍摄的荧光图像计算NPQ（非光化学猝灭）和Yield（光系统II光化学效率）图像。害区NPQ值显著降低，NPQ图像可用于量化光合损伤。但是，产量的下降幅度不如同化速率的下降幅度大。这表明产量图像不适合诊断除草剂对附着植物叶片的光合损伤。

In this research, hyper-spectral imaging systems for diagnosis of growth and photosynthesis were developed. Growth and chlorophyll contents of wheat plants growing in field areas with different fertilizer application were estimated by the band ratio of 550 nm and 900 nm images measured using this system. Meanwhile, a fluorescence spectrometry is used to non-destructively and remotely obtain information on pigments, cell structure, physiological functions of plant leaves. Excitation-emission matrices of water-stressed spinach leaves in the dark were measured by a 3-D fluorescence spectrophotometer, and changes with time of these matrices were analyzed. F450/F680 and F450/F725 excited by short-wavelength ultraviolet rays (for example, 330nm) were suitable to detect changes of relative water content in spinach leaves. Using a developed chlorophyll (Chl) fluorescence imaging system, the photosynthetic effects of a commercially available soil-application type urea herbicide on attached Cucumis sativus L. leaves were analyzed. The inhibitions of primary electron transport in injured areas were detected from Chl fluorescence induction (CFI) images (Changes in intensity of Chl fluorescence during dark-light transition) taken by the CFI method. NPQ (non-photochemical quenching) and Yield (photosystem II photochemical efficiency) images were calculated from fluorescence images taken by the saturation pulse method. NPQ was reduced greatly in injured areas and NPQ images were useful to quantify the photosynthetic injuries. However, Yield was not reduced as much as the decrease in assimilation rate. This showed that Yield images were not suitable for diagnosis of the photosynthetic injuries of attached plant leaves caused by the herbicide.