基于高光谱影像和 SIF 检索的辐射转移 Vcmax 估计，以评估雨养和灌溉植物表型试

摘要：植物的光合特性可能表明其在田间对胁迫的耐受性和表现，因此准确评估这些特性在表型试验中至关重要。最大 羧化速率 (Vcmax) 是估算 CO2 同化 (A) 的关键参数，因为它控制着 CO2 固定速率。本研究通过反演土壤冠层光合作 用和能量观测 (SCOPE) 模型来估计 Vcmax，并利用精准农业技术中可用的传感器分辨率，证明了结合机载太阳诱导叶 绿素荧光 (SIF) 和高光谱图像的实用性。在 2015-2018 年生长季，在三个小麦表型试验田中对 Vcmax 进行了量化，包 括雨养和灌溉条件。空中观测活动使用两个高光谱传感器进行，覆盖 400–850 nm（（ 20 厘米分辨率）和 950–1750 nm（（ 70 厘米分辨率）光谱区域，并使用热像仪（25 厘米分辨率）覆盖 8–14 μm 区域。模型估计值和实地测量的 Vcmax 之间 的验证具有统计学意义（（r2 = 0.77；p 值 ≤2.2e−16），并且 Vcmax 与灌溉和雨养条件下的净同化可靠相关（（r2 分别为 0.65 和 0.5）。相比之下，模拟叶绿素含量（（ Cab）和空气衍生的结构和叶绿素指标（（ NDVI 和 PSSRb）与灌溉地块的同化率 缺乏显著相关性，而同化率与作物水分胁迫指数（（CWSI）之间的关系在雨养地块中并不显著。在灌溉条件下，遥感 Vcmax 的超高灵敏度可能与其对其他指数中观察到的高冠层密度造成的扭曲的稳健性有关。遥感检索 Vcmax 以及本研究中展 示的方法与高通量植物表型分析和精准农业应用直接相关。

关键词：太阳诱导叶绿素荧光、作用域、高分辨率高光谱、叶片最大羧化速率 (Vcmax) 、水分胁迫

期刊：Remote Sensing of Environment

DOI：https://DOI.org/10.1016/j.rse.2019.05.005

设备：GaiaSky

Radiative transfer Vcmax estimation from hyperspectral imagery and SIF retrievals to assess photosynthetic performance in rainfed and irrigated plant phenotyping trials

Abstract：Plant photosynthetic traits may be indicative of stress tolerance and performance in the field, making their accurate assessment critical in phenotyping trials. The maximum rate of carboxylation (Vcmax) is a key parameter for estimating CO2 assimilation (A), as it controls the CO2 fixation rate. This study demonstrates the utility of combining airborne-based solar-induced chlorophyll fluorescence (SIF) and hyperspectral imagery through the inversion of the Soil-Canopy Observation of Photosynthesis and Energy (SCOPE) model to estimate Vcmax, using sensor resolutions available in precision agriculture technologies. Vcmax was quantified in three wheat phenotyping experimental fields during the 2015–2018 growing seasons, comprising both rainfed and irrigated conditions. Airborne campaigns were carried out with two hyperspectral sensors, covering the 400–850 nm (20 cm resolution) and 950–1750 nm (70 cm resolution) spectral regions, and with a thermal camera (25 cm resolution) in the 8–14 μm region. Validation between model-estimated and field-measured Vcmax was statistically significant (r2 = 0.77; p-value ≤2.2e−16), and Vcmax was reliably associated with net assimilation both in irrigated and rainfed conditions (r2 = 0.65 and 0.5, respectively). By contrast, simulated chlorophyll content (Cab) and airborne-derived structural and chlorophyll indicators (NDVI and PSSRb) lacked significant correlations with assimilation rate in irrigated plots, while the relationship between assimilation rate and the crop water stress index (CWSI) was not significant in rainfed plots. The superior sensitivity of remotely-sensed Vcmax under irrigated conditions was likely related to its robustness to distortions from high canopy densities observed in other indices. The remote sensing retrieval of Vcmax, and the methodology demonstrated in this study is directly relevant for high-throughput plant phenotyping and for precision agriculture applications.

Keywords：Sun-induced chlorophyll fluorescence SCOPE High-resolution hyperspectral Leaf maximum carboxylation rate (Vcmax) Water stress