Improving the ability of the photochemical reflectance index to track canopy light use efficiency through differentiating sunlit and shaded leaves

Zhang, Qian; Chen, Jing M.; Ju, Weimin; Wang, Huimin; Qiu, Feng; Yang, Fengting; Fan, Weiliang; Qing, Huang; Ying-ping, Wang; Feng, Yongkang; Wang, Xiaojie; Zhang, Fangmin

doi:10.1016/j.rse.2017.03.012

Cited by 48 publications

(65 citation statements)

References 96 publications

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“…In fact, the varying ranges of daily PRI over weeks in our mangrove ecosystem were several times larger than the difference in seasonally mean daily PRI (Figure a), and daily PRI variations were tightly linked to daily PAR variations with PRI peaks (troughs) corresponding to PAR troughs (peaks; Figures a, c, and a). Daily PRI was also strongly correlated to clearness index, which is consistent with the findings by Zhang et al () focusing on evergreen forests in subtropical climate (Figure d). Based on these findings, we conclude that, same as the diurnal variation in half‐hourly PRI, the seasonal variations in daily PRI were also dominated by change in daily radiation regime.…”

Section: Discussionsupporting

confidence: 91%

“…To exclude potential abnormal spectral signals at dawn or dusk (Soudani et al, ), only half‐hourly spectral data of PRI and NDVI with instantaneous solar elevation >15° (Zhang et al, ) were used for further analysis at the diurnal scale. This criterion was also applied to the estimation of half‐hourly LUE to avoid data with bad quality at low light conditions.…”

Section: Methodsmentioning

confidence: 99%

“…This criterion was also applied to the estimation of half‐hourly LUE to avoid data with bad quality at low light conditions. For the analysis at seasonal scale, only half‐hourly data (spectral, meteorological, tidal, and carbon flux measurements) acquired from 10:00 to 15:30 were used to calculate daily values to avoid abnormal values around early morning and late afternoon (Zhang et al, ). In addition, measurements on rainy days were excluded in data analysis due to inaccuracy of both spectral and flux measurements under rainy conditions.…”

Section: Methodsmentioning

confidence: 99%

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Linking In Situ Photochemical Reflectance Index Measurements With Mangrove Carbon Dynamics in a Subtropical Coastal Wetland

et al. 2019

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Photochemical reflectance index (PRI) has been found to be closely related with vegetation photosynthetic phenology in many ecosystems including boreal evergreen, but its ability to track carbon dynamics in low‐latitude evergreen mangrove ecosystems has rarely been assessed. To fill up this gap, this paper explored potential mangrove PRI‐carbon links and their environmental controls across temporal scales (diurnal and seasonal), based on 1‐year continuous high‐resolution (half‐hourly) time series measurements of spectral signals, eddy covariance carbon fluxes, and multiple environmental factors at a subtropical mangrove wetland of southeastern China. The diurnal variation of half‐hourly mangrove PRI, a U‐shaped changing pattern, was consistent with previous PRI studies on boreal evergreen, while the seasonal variation of daily mangrove PRI did not experience a hump‐shaped changing pattern as in boreal evergreen. Diurnal and seasonal mangrove PRI variations were significantly correlated with meteorological (radiation and vapor pressure deficit) and carbon‐related parameters (gross primary productivity, net ecosystem exchange, and light use efficiency), and the strength of diurnal PRI‐carbon correlations varied with meteorological factors with stronger correlations at enhanced radiation and vapor pressure deficit. Our results further indicated that physiology‐related PRI performed better than conventional structure‐related normalized difference vegetation index in tracking mangrove photosynthetic parameters. To the best of our knowledge, this is the first study to explore the link between high‐frequency PRI and carbon dynamics across temporal scales in natural mangrove ecosystems. The PRI‐carbon linkage confirmed by this study will improve our understanding of temporal variations in photosynthetic carbon dynamics in mangrove ecosystems.

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Section: Discussionsupporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Linking In Situ Photochemical Reflectance Index Measurements With Mangrove Carbon Dynamics in a Subtropical Coastal Wetland

et al. 2019

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“…Hmimina et al [25] used ∆PRI to detect changes in LUE induced by water limitation in oak, beech, and pine saplings. Zhang et al [78] used ∆PRI to track photosynthesis responses to experimental drought and warming in a Mediterranean shrubland. The lower Chla+b/Carx+c in our study did not facilitate separating the effect of drought using PRI, but the higher carotenoid levels in HI-HT3 did increase the magnitude of ∆PRI in saplings stressed by high temperature and drought.…”

Section: Evaluation Of Water Limitation From Primentioning

confidence: 99%

“…Separate modelling between sunlit and shaded portions of canopy yielding different Chla+b/Carx+c and PRI was the most efficient way to simulate daily photosynthesis from multi-angular PRI measurements [81]. Contrary to the direct use of PRI, recent pioneering studies employing procedures to estimate ∆PRI from PRI 0 and PRI are leading to attempts to use ∆PRI for the purpose of estimating various stresses [25,75,78]. We also suggest that ability to discern between the two effects of Chla+b/Carx+c and daily dynamics in xanthophylls in PRI 0 should play a crucial role in evaluating ∆PRI.…”

Section: Evaluation Of Water Limitation From Primentioning

confidence: 99%

Potential of Photochemical Reflectance Index for Indicating Photochemistry and Light Use Efficiency in Leaves of European Beech and Norway Spruce Trees

et al. 2018

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Hyperspectral reflectance is becoming more frequently used for measuring the functions and productivity of ecosystems. The purpose of this study was to re-evaluate the potential of the photochemical reflectance index (PRI) for evaluating physiological status of plants. This is needed because the reasons for variation in PRI and its relationships to physiological traits remain poorly understood. We examined the relationships between PRI and photosynthetic parameters in evergreen Norway spruce and deciduous European beech grown in controlled conditions during several consecutive periods of 10-12 days between which the irradiance and air temperature were changed stepwise. These regime changes induced significant changes in foliar biochemistry and physiology. The responses of PRI corresponded particularly to alterations in the actual quantum yield of photosystem II photochemistry (Φ PSII ). Acclimation responses of both species led to loss of PRI sensitivity to light use efficiency (LUE). The procedure of measuring PRI at multiple irradiance-temperature conditions has been designed also for testing accuracy of ∆PRI in estimating LUE. A correction mechanism of subtracting daily measured PRI from early morning PRI has been performed to account for differences in photosynthetic pigments between irradiance-temperature regimes. Introducing ∆PRI, which provided a better estimate of non-photochemical quenching (NPQ) compared to PRI, also improved the accuracy of LUE estimation. Furthermore, ∆PRI was able to detect the effect of drought, which is poorly observable from PRI.

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Tracking of Vegetation Carbon Dynamics from 2001 to 2016 by MODIS GPP in HKH Region

Chao

Che

Shang

et al. 2019

Carbon Management for Promoting Local Livelihood in the Hindu Kush Himalayan (HKH) Region

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Improving the ability of the photochemical reflectance index to track canopy light use efficiency through differentiating sunlit and shaded leaves

Cited by 48 publications

References 96 publications

Linking In Situ Photochemical Reflectance Index Measurements With Mangrove Carbon Dynamics in a Subtropical Coastal Wetland

Linking In Situ Photochemical Reflectance Index Measurements With Mangrove Carbon Dynamics in a Subtropical Coastal Wetland

Potential of Photochemical Reflectance Index for Indicating Photochemistry and Light Use Efficiency in Leaves of European Beech and Norway Spruce Trees

Tracking of Vegetation Carbon Dynamics from 2001 to 2016 by MODIS GPP in HKH Region

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