Zolin Yuriy, Popova Alyona, Yudina Lyubov, Grebneva Kseniya, Abasheva Karina, Sukhov Vladimir, Sukhova Ekaterina
Department of Biophysics, N.I. Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia.
Plants (Basel). 2025 Apr 23;14(9):1284. doi: 10.3390/plants14091284.
Soil drought and salinization are key abiotic stressors for agricultural plants; the development of methods of their early detection is an important applied task. Measurement of red-green-blue (RGB) indices, which are calculated on basis of color images, is a simple method of proximal and remote sensing of plant health under the action of stressors. Potentially, RGB indices can be used to estimate narrow-band reflectance indices and/or photosynthetic parameters in plants. Analysis of this problem was the main task of the current work. We investigated relationships of six RGB indices (r, g, b, ExG, VEG, and VARI) to widely used narrow-band reflectance indices (the normalized difference vegetation index, NDVI, and photochemical reflectance index, PRI) and the potential quantum yield of photosystem II (Fv/Fm) in wheat and pea plants under soil drought and salinization. It was shown that investigated RGB indices, NDVI, PRI, and Fv/Fm were significantly changed under the action of both stressors; changes in some RGB indices (e.g., ExG) were initiated on the early stage of action of drought or salinization. Correlation analysis showed that RGB indices (especially, ExG, VARY, and g) were strongly related to the NDVI, PRI, and Fv/Fm; linear regressions between these values were calculated. It means that RGB indices measured by simple and low-cost color cameras can be used to estimate plant parameters (NDVI, PRI, and Fv/Fm) requiring sophisticated equipment to measure.
土壤干旱和盐渍化是农业植物面临的关键非生物胁迫因素；开发早期检测方法是一项重要的应用任务。基于彩色图像计算的红-绿-蓝（RGB）指数测量，是在胁迫因素作用下对植物健康进行近距离和遥感的一种简单方法。RGB指数有可能用于估计植物中的窄带反射率指数和/或光合参数。对这一问题的分析是当前工作的主要任务。我们研究了六种RGB指数（r、g、b、ExG、VEG和VARI）与广泛使用的窄带反射率指数（归一化植被指数，NDVI，和光化学反射率指数，PRI）以及土壤干旱和盐渍化条件下小麦和豌豆植株光系统II的潜在量子产率（Fv/Fm）之间的关系。结果表明，在两种胁迫因素作用下，所研究的RGB指数、NDVI、PRI和Fv/Fm均发生了显著变化；一些RGB指数（如ExG）的变化在干旱或盐渍化作用的早期就开始了。相关性分析表明，RGB指数（特别是ExG、VARY和g）与NDVI、PRI和Fv/Fm密切相关；计算了这些值之间的线性回归。这意味着，通过简单且低成本的彩色相机测量的RGB指数可用于估计需要复杂设备测量的植物参数（NDVI、PRI和Fv/Fm）。
