Driever Steven M, Mossink Leon, Ocaña Diego Nuñez, Kaiser Elias
Centre for Crop Systems Analysis, Wageningen University and Research, Wageningen, the Netherlands.
Horticulture and Product Physiology, Wageningen University and Research, Wageningen, the Netherlands.
Plant Sci. 2023 Apr;329:111626. doi: 10.1016/j.plantsci.2023.111626. Epub 2023 Feb 3.
Plant breeding for increased crop water use efficiency or drought stress resistance requires methods to quickly assess the transpiration rate (E) and stomatal conductance (g) of a large number of individual plants. Several methods to measure E and g exist, each of which has its own advantages and shortcomings. To add to this toolbox, we developed a method that uses whole-plant thermal imaging in a controlled environment, where aerial humidity is changed rapidly to induce changes in E that are reflected in changes in leaf temperature. This approach is based on a simplified energy balance equation, without the need for a reference material or complicated calculations. To test this concept, we built a double-sided, perforated, open-top plexiglass chamber that was supplied with air at a high flow rate (35 L min) and whose relative humidity (RH) could be switched rapidly. Measurements included air and leaf temperature as well as RH. Using several well-watered and drought stressed genotypes of Arabidopsis thaliana that were exposed to multiple cycles in RH (30-50 % and back), we showed that leaf temperature as measured in our system correlated well with E and g measured in a commercial gas exchange system. Our results demonstrate that, at least within a given species, the differences in leaf temperature under several RH can be used as a proxy for E and g. Given that this method is fairly quick, noninvasive and remote, we envision that it could be upscaled for work within rapid plant phenotyping systems.
为提高作物水分利用效率或抗旱性而进行的植物育种需要能够快速评估大量单株植物蒸腾速率（E）和气孔导度（g）的方法。现有多种测量E和g的方法，每种方法都有其优缺点。为丰富这一方法库，我们开发了一种在可控环境中利用整株热成像的方法，在该环境中快速改变空气湿度以诱导E的变化，这种变化会反映在叶片温度的变化上。该方法基于一个简化的能量平衡方程，无需参考材料或复杂计算。为验证这一概念，我们构建了一个双面、有孔、顶部开放的有机玻璃室，该室以高流速（35升/分钟）供应空气，其相对湿度（RH）可快速切换。测量内容包括空气温度、叶片温度以及相对湿度。我们使用了几种充分浇水和遭受干旱胁迫的拟南芥基因型，使其经历多个RH循环（30%-50%之间来回变化），结果表明，我们系统中测量的叶片温度与商业气体交换系统中测量的E和g具有良好的相关性。我们的结果表明，至少在给定物种内，几种RH条件下叶片温度的差异可作为E和g的替代指标。鉴于该方法相当快速、非侵入性且具有远程测量的特点，我们设想它可扩大规模用于快速植物表型分析系统。
