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

在这项研究中，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波段图像，估算了不同施肥量的田间小麦植株的生长和叶绿素含量。同时，利用荧光光谱非破坏性地远程获取植物叶片的色素、细胞结构、生理功能等信息。用三维荧光分光光度计测定了水胁迫下菠菜叶片在黑暗中的激发发射矩阵，并分析了这些矩阵随时间的变化。短波紫外线(如330 nm)激发的F450/F680和F450/F725适合于检测菠菜叶片相对含水量的变化。利用自行研制的叶绿素(Chl)荧光成像系统，研究了市售土用型尿素除草剂对黄瓜附着叶的光合作用效应。用荧光诱导(CFI)法检测损伤区初级电子传递的抑制情况。根据饱和脉冲法拍摄的荧光图像计算NPQ(非光化学猝灭)和Year(光系统II光化学效率)图像。损伤区NPQ显著降低，NPQ图像有助于量化光合作用损伤。然而，产量的下降没有同化率的下降那么大。这表明，产量图像不适合于诊断除草剂对附着植物叶片的光合作用伤害。

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.