Articles
Hyperspectral plant traits and fluorescence emission dynamics under increasing water stress levels show diverging trends across species
Article number
1409_56
Pages
445 – 452
Language
English
Abstract
Hyperspectral remote sensing progress achieved over the last 20 years has permitted the development of new spectral traits quantified by radiative transfer models directly linked to plant functioning.
In addition to the well-established relationships between canopy temperature and transpiration used as a water stress indicator, advances with narrow-band hyperspectral imagers have demonstrated that chlorophyll fluorescence emission is detectable within the PS-I and PS-II spectral region.
Other photosynthetic plant traits retrieved by hyperspectral imaging such as chlorophyll a+b, carotenoids, anthocyanins, and xanthophylls have demonstrated sensitivity to early symptoms of water stress, nutrient deficiencies and vascular-colonizing pathogens before visual detection.
This work presents recent developments assessing the sensitivity and the dynamics of hyperspectral traits under varying water stress levels in almond and olive orchards.
Circa 380,000 olive and almond trees across three geographical regions in southern Spain were scanned with airborne hyperspectral and thermal imaging sensors over two summer growing seasons.
This approach enabled the identification of trees with sustained across-season water status and clustering trees into consistent water stress levels using the thermal-based CWSI index.
Results of the radiative transfer model inversion and machine learning algorithms showed distinct dynamics (olive vs. almond) of the spectral traits analysed as a function of increasing levels of water stress.
When aiming at detecting water stress with hyperspectral-thermal algorithms, the relative importance of the water stress indicator CWSI decreases as water stress increases.
In turn, physiological traits related to highly dynamic photosynthetic plant pigments increase their importance within the water stress detection algorithm.
Distinct results obtained for almond vs. olive due to specific adaptive mechanisms to water stress are presented, particularly CWSI, PRIn, anthocyanins and solar-induced fluorescence when compared against structural traits.
In addition to the well-established relationships between canopy temperature and transpiration used as a water stress indicator, advances with narrow-band hyperspectral imagers have demonstrated that chlorophyll fluorescence emission is detectable within the PS-I and PS-II spectral region.
Other photosynthetic plant traits retrieved by hyperspectral imaging such as chlorophyll a+b, carotenoids, anthocyanins, and xanthophylls have demonstrated sensitivity to early symptoms of water stress, nutrient deficiencies and vascular-colonizing pathogens before visual detection.
This work presents recent developments assessing the sensitivity and the dynamics of hyperspectral traits under varying water stress levels in almond and olive orchards.
Circa 380,000 olive and almond trees across three geographical regions in southern Spain were scanned with airborne hyperspectral and thermal imaging sensors over two summer growing seasons.
This approach enabled the identification of trees with sustained across-season water status and clustering trees into consistent water stress levels using the thermal-based CWSI index.
Results of the radiative transfer model inversion and machine learning algorithms showed distinct dynamics (olive vs. almond) of the spectral traits analysed as a function of increasing levels of water stress.
When aiming at detecting water stress with hyperspectral-thermal algorithms, the relative importance of the water stress indicator CWSI decreases as water stress increases.
In turn, physiological traits related to highly dynamic photosynthetic plant pigments increase their importance within the water stress detection algorithm.
Distinct results obtained for almond vs. olive due to specific adaptive mechanisms to water stress are presented, particularly CWSI, PRIn, anthocyanins and solar-induced fluorescence when compared against structural traits.
Authors
T. Poblete, V. Gonzalez-Dugo, P.J. Zarco-Tejada
Keywords
CWSI, thermal, radiative transfer, water stress, temporal dynamics
Online Articles (64)