Truax Kelly, Dulai Henrietta, Misra Anupam, Kuhne Wendy, Smith Celia, Bongolan-Aquino Ciara
Department of Earth Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA.
Savannah River National Laboratory, Aiken, SC 29831, USA.
Plants (Basel). 2024 Jul 24;13(15):2031. doi: 10.3390/plants13152031.
Chlorophyll has long been used as a natural indicator of plant health and photosynthetic efficiency. Laser-induced fluorescence (LIF) is an emerging technique for understanding broad spectrum organic processes and has more recently been used to monitor chlorophyll response in plants. Previous work has focused on developing a LIF technique for imaging moss mats to identify metal contamination with the current focus shifting toward application to moss fronds and aiding sample collection for chemical analysis. Two laser systems (CoCoBi a Nd:YGa pulsed laser system and Chl-SL with two blue continuous semiconductor diodes) were used to collect images of moss fronds exposed to increasing levels of Cu (1, 10, and 100 nmol/cm) using a CMOS camera. The best methods for the preprocessing of images were conducted before the analysis of fluorescence signatures were compared to a control. The Chl-SL system performed better than the CoCoBi, with dynamic time warping (DTW) proving the most effective for image analysis. Manual thresholding to remove lower decimal code values improved the data distributions and proved whether using one or two fronds in an image was more advantageous. A higher DTW difference from the control correlated to lower chlorophyll a/b ratios and a higher metal content, indicating that LIF, with the aid of image processing, can be an effective technique for identifying Cu contamination shortly after an event.
叶绿素长期以来一直被用作植物健康和光合效率的天然指标。激光诱导荧光（LIF）是一种用于理解广谱有机过程的新兴技术，最近已被用于监测植物中的叶绿素反应。先前的工作主要集中在开发一种用于苔藓垫成像以识别金属污染的LIF技术，目前的重点正转向应用于苔藓叶状体并辅助化学分析的样品采集。使用两个激光系统（CoCoBi，一种Nd:YGa脉冲激光系统，以及带有两个蓝色连续半导体二极管的Chl-SL），通过CMOS相机采集暴露于不同浓度铜（1、10和100 nmol/cm）的苔藓叶状体图像。在将荧光特征分析与对照进行比较之前，先对图像进行了最佳预处理方法。Chl-SL系统的表现优于CoCoBi，动态时间规整（DTW）被证明是最有效的图像分析方法。通过手动阈值化去除较低的十进制代码值改善了数据分布，并证明了在图像中使用一片或两片叶状体哪个更具优势。与对照相比，DTW差异越大，叶绿素a/b比值越低，金属含量越高，这表明借助图像处理的LIF可以成为在事件发生后不久识别铜污染的有效技术。
