Extending Fluspect to simulate xanthophyll driven leaf reflectance dynamics

0489468 - ÚVGZ 2019 RIV US eng J - Článek v odborném periodiku
Vilfan, N. - Van der Tol, C. - Yang, P. - Wyber, R. - Malenovský, Zbyněk - Robinson, S. A. - Verhoef, A.
Extending Fluspect to simulate xanthophyll driven leaf reflectance dynamics.
Remote Sensing of Environment. Roč. 211, Jun (2018), s. 345-356. ISSN 0034-4257. E-ISSN 1879-0704
Institucionální podpora: RVO:86652079
Klíčová slova: Fluspect * Leaf chlorophyll fluorescence * pri * Reflectance * scope * Xanthophyll cycle
Obor OECD: Environmental sciences (social aspects to be 5.7)
Impakt faktor: 8.218, rok: 2018

The xanthophyll cycle regulates the energy flow to photosynthetic reaction centres of plant leaves. Changes in the de-epoxidation state (DEPS) of xanthophyll cycle pigments can be observed as changes in the leaf absorption of light with wavelengths between 500 to 570 nm. These spectral changes can be a good remote sensing indicator of the photosynthetic efficiency, and are traditionally quantified with a two-band physiologically based optical index, the Photochemical Reflectance Index (PRI). In this paper, we present an extension of the plant leaf radiative transfer model Fluspect (Fluspect-CX) that reproduces the spectral changes in a wide band of green reflectance: a radiative transfer analogy to the PRI. The idea of Fluspect-CX is to use in vivo specific absorption coefficients for two extreme states of carotenoids, representing the two extremes of the xanthophyll de-epoxidation, and to describe the intermediate states as a linear mixture of these two states. The ‘photochemical reflectance parameter’ (C x ) quantifies the relative proportion of the two states. Fluspect-CX simulates leaf chlorophyll fluorescence (ChlF) excitation-emission matrices, as well as reflectance (R) and transmittance (T) spectra as a function of leaf structure, pigment contents and C x . We describe the calibration of the model and test its performance using various experimental datasets. Furthermore, we retrieved C x from optical measurements of various datasets. The retrieved C x correlates well with xanthophyll DEPS (R 2 = 0.57), as well with non-photochemical quenching (NPQ) of fluorescence (R 2 = 0.78). The correlation with NPQ enabled us to incorporate Fluspect-CX in the model SCOPE to scale the processes to the canopy level. Introducing the dynamic green reflectance into a radiative transfer model provides new means to study chlorophyll fluorescence and PRI dynamics on leaf and canopy scales, which is crucial for the remote sensing.
Trvalý link: http://hdl.handle.net/11104/0283877