Non-destructive estimation of foliar carotenoid content of tree species using merged vegetation indices

Fabian E Fassnacht; Stefanie Stenzel; Anatoly A Gitelson

doi:10.1016/j.jplph.2014.11.003

Non-destructive estimation of foliar carotenoid content of tree species using merged vegetation indices

J Plant Physiol. 2015 Mar 15:176:210-7. doi: 10.1016/j.jplph.2014.11.003. Epub 2014 Nov 27.

Authors

Fabian E Fassnacht¹, Stefanie Stenzel², Anatoly A Gitelson³

Affiliations

¹ Karlsruhe Institute of Technology, Institute of Geography and Geoecology, Kaiserstraße 12, 76131 Karlsruhe, Germany. Electronic address: fabian.fassnacht@kit.edu.
² Karlsruhe Institute of Technology, Institute of Geography and Geoecology, Kaiserstraße 12, 76131 Karlsruhe, Germany. Electronic address: stefanie.stenzel@kit.edu.
³ Israel Institute of Technology (Technion), Civil and Environmental Engineering, Rabin Building, 32000 Haifa, Israel; School of Natural Resources, University of Nebraska, Lincoln, USA. Electronic address: agitelson2@unl.edu.

PMID: 25512167
DOI: 10.1016/j.jplph.2014.11.003

Abstract

Leaf pigment content is an important indicator of plant status and can serve to assess the vigor and photosynthetic activity of plants. The application of spectral information gathered from laboratory, field and remote sensing-based spectrometers to non-destructively assess total chlorophyll (Chl) content of higher plants has been demonstrated in earlier studies. However, the precise estimation of carotenoid (Car) content with non-destructive spectral measurements has so far not reached accuracies comparable to the results obtained for Chl content. Here, we examined the potential of a recently developed angular vegetation index (AVI) to estimate total foliar Car content of three tree species. Based on an iterative search of all possible band combinations, we identified a best candidate AVIcar. The identified index showed quite close but essentially not linear relation with Car contents of the examined species with increasing sensitivity to high Car content and a lack of sensitivity to low Car content for which earlier proposed vegetation indices (VI) performed better. To make use of the advantages of both VI types, we developed a simple merging procedure, which combined the AVIcar with two earlier proposed carotenoid indices. The merged indices had close linear relationship with total Car content and outperformed all other examined indices. The merged indices were able to accurately estimate total Car content with a percental root mean square error (%RMSE) of 8.12% and a coefficient of determination of 0.88. Our findings were confirmed by simulations using the radiative transfer model PROSPECT-5. For simulated data, the merged indices again showed a quasi linear relationship with Car content. This strengthens the assumption that the proposed merged indices have a general ability to accurately estimate foliar Car content. Further examination of the proposed merged indices to estimate foliar Car content of other plant species is desirable to prove the general applicability of the index for non-destructive estimation of Car from leaf reflectance data.

Keywords: Angular vegetation index; Carotenoids; Leaf optics; Non-destructive assessment; Reflectance.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acer / chemistry*
Aesculus / chemistry*
Carotenoids / analysis*
Chlorophyll / metabolism
Computer Simulation
Fagus / chemistry*
Plant Leaves / metabolism*
Trees / chemistry*

Substances

Chlorophyll
Carotenoids