Lhotáková Zuzana, Neuwirthová Eva, Potůčková Markéta, Červená Lucie, Hunt Lena, Kupková Lucie, Lukeš Petr, Campbell Petya, Albrechtová Jana
Department of Plant Experimental Biology, Faculty of Science, Charles University, Viničná 5, 12800, Prague, Czech Republic.
Department of Applied Geoinformatics and Cartography, Faculty of Science, Charles University, Albertov 6, 12800, Prague, Czech Republic.
Sci Rep. 2025 Jan 13;15(1):1855. doi: 10.1038/s41598-024-84052-5.
A wide range of portable chlorophyll meters are increasingly being used to measure leaf chlorophyll content as an indicator of plant performance, providing reference data for remote sensing studies. We tested the effect of leaf anatomy on the relationship between optical assessments of chlorophyll (Chl) against biochemically determined Chl content as a reference. Optical Chl assessments included measurements taken by four chlorophyll meters: three transmittance-based (SPAD-502, Dualex-4 Scientific, and MultispeQ 2.0), one fluorescence-based (CCM-300), and vegetation indices calculated from the 400-2500 nm leaf reflectance acquired using an ASD FieldSpec and a contact plant probe. Three leaf types with different anatomy were included: dorsiventral laminar leaves, grass leaves, and needles. On laminar leaves, all instruments performed well for chlorophyll content estimation (R > 0.80, nRMSE < 15%), regardless of the variation in their specific internal structure (mesomorphic, scleromorphic, or scleromorphic with hypodermis), similarly to the performance of four reflectance indices (R > 0.90, nRMSE < 16%). For grasses, the model to predict chlorophyll content across multiple species had low performance with CCM-300 (R = 0.45, nRMSE = 11%) and failed for SPAD. For Norway spruce needles, the relation of CCM-300 values to chlorophyll content was also weak (R = 0.45, nRMSE = 11%). To improve the accuracy of data used for remote sensing algorithm development, we recommend calibration of chlorophyll meter measurements with biochemical assessments, especially for species with anatomy other than laminar dicot leaves. The take-home message is that portable chlorophyll meters perform well for laminar leaves and grasses with wider leaves, however, their accuracy is limited for conifer needles and narrow grass leaves. Species-specific calibrations are necessary to account for anatomical variations, and adjustments in sampling protocols may be required to improve measurement reliability.
各种各样的便携式叶绿素仪越来越多地被用于测量叶片叶绿素含量，以此作为植物生长状况的指标，为遥感研究提供参考数据。我们测试了叶片解剖结构对以生化测定的叶绿素含量为参考的叶绿素光学评估之间关系的影响。叶绿素光学评估包括使用四种叶绿素仪进行的测量：三种基于透射率的仪器（SPAD - 502、Dualex - 4 Scientific和MultispeQ 2.0）、一种基于荧光的仪器（CCM - 300），以及根据使用ASD FieldSpec和接触式植物探头获取的400 - 2500 nm叶片反射率计算的植被指数。研究包括三种具有不同解剖结构的叶片类型：两面叶、草叶和针叶。对于两面叶，所有仪器在叶绿素含量估计方面表现良好（R > 0.80，nRMSE < 15%），无论其具体内部结构（中型、硬型或有皮下组织的硬型）如何变化，这与四种反射率指数的表现类似（R > 0.90，nRMSE < 16%）。对于草类，使用CCM - 300预测多个物种叶绿素含量的模型表现较差（R = 0.45，nRMSE = 11%），而SPAD则无法进行预测。对于挪威云杉针叶，CCM - 300值与叶绿素含量之间的关系也很弱（R = 0.45，nRMSE = 11%）。为提高用于遥感算法开发的数据准确性，我们建议用生化评估对叶绿素仪测量进行校准，特别是对于具有非两面双子叶叶片解剖结构的物种。关键信息是，便携式叶绿素仪对于两面叶和叶片较宽的草类表现良好，然而，它们对于针叶树针叶和窄草叶的准确性有限。需要进行物种特异性校准以考虑解剖结构的变化，并且可能需要调整采样方案以提高测量可靠性。
