Non-invasive monitoring of environmental stress on plant using functional optical coherence tomography

利用光学相干层析成像技术（OCT）和生物散斑的统计特性，建立了一种新的非侵入性监测植物在环境胁迫下生物活性的方法。 生物斑点是由细胞内细胞器的动态运动产生的，可以反映植物叶片的生物活性。 实验证明，该功能性OCT系统可以三维观察臭氧胁迫下植物的生物学活动。 为了分析生物散斑信号，提出并检验了两种类型的分析。 一种是基于信号的波动幅度（标准偏差）。 另一种是分析信号的时间特性，即，信号的自动解调功能。臭氧暴露实验结果表明，这两种方法可以立即检测到一个独立的响应环境条件。

In this study, a novel and non-invasive monitoring method of biological activities of plant under environmental stress was developed using an optical coherence tomography (OCT) together with a statistical properties of biospeckle. The biospeckle is generated by the dynamic motion of organelles inside a cell, and hence can reflect the biological activities of plant leaf. The proposed functional OCT system experimentally demonstrated to observe three-dimensionally the biological activities of plant under ozone stress. To analyze the biospeckle signal, two types of analysis were proposed and examined. One is based on the magnitude of the fluctuation (standard deviation) of the signal. The other one is to analyze temporal characteristics of the signal, i.e., a autocorrelaton function of the signal. As experimental results of ozone exposure, it was revealed that those two methods could immediately detect an independent response about environmental condition.