Simple reflectance indices track heat and water stress-induced changes in steady-state chlorophyll fluorescence at the canopy scale

Dobrowski, Solomon Z.; Pushnik, James C.; Zarco‐Tejada, Pablo J.; Ustin, Susan L.

doi:10.1016/j.rse.2005.05.006

Cited by 275 publications

(174 citation statements)

References 49 publications

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“…Under severe water and heat stress, downregulation of the whole-canopy LUE due to stomata closure should be detectable through PRI, but only limited information suggests a close relationship between plant water status and PRI [48,73]. Moreover, there are reports of difficulties with tracking LUE changes in drought-stressed vegetation that may originate from enhancement of respiration processes [74][75][76].…”

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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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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“…Nitrogen (N) is an indispensable nutrient for improving crop field and N content is also a significant nutrient diagnosis indicator that governs canopy carbon assimilation (Oppelt and Mauser 2004). Thus, it is significant to precisely estimate the N content of crops leaf in a large area scale, which can gain the distribution of N content that can be used by farmers in fertilization and to obtain the discipline of leaf energy exchange in agroecological system that can be utilized to manage the number of vegetation (Dobrowski et al 2005).…”

mentioning

confidence: 99%

Application of fluorescence spectrum to precisely inverse paddy rice nitrogen content

Yang¹,

Shi²,

Gong³

et al. 2015

PLANT SOIL ENVIRON

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Paddy rice is important for Chinese agriculture and crop production, which largely depends on the leaf nitrogen (N) levels. The purpose of this study is to discuss the relationship between the fluorescence parameters and leaf N content of paddy rice and to test their performance in inversing N content of crops through back-propagation (B-P) neural network. In the correlative analysis of the fluorescence parameters and the N content, we found that the correlation between fluorescence ratios (F740/F685 and F685/F525 (F740, F685, F525 -intensity of fluorescence at 740, 685 and 525 nm, respectively)) and the N content (R 2 are 0.735 and 0.4342, respectively) is weaker than that between the intensity of fluorescence peaks (F685 and F740) and N content (R 2 are 0.9743 and 0.9686, respectively). Our studies show that the accuracy and precision of N content inversion which is acquired from the intensity of fluorescence peaks through the B-P neural network model are significantly improved (root mean square error (MSRE) = 0.1702, the residual changes between -0.1-0.1 mg/g) compared with the fluorescence ratio (MSRE = 0.3655, the residual changes from -0.3-0.3 mg/g). Results demonstrate that the intensity of fluorescence peaks can be as a characteristic parameter to estimate N content of crops leaf. The B-P neural network model will be serviceable approach in inversing N content of paddy leaf.

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“…The PRI has been used as a pre-visual indicator of water stress at the leaf scale (Thenot et al, 2010) and canopy scale (Dobrowski et al, 2005). The PRI is calculated to obtain the average per plant of that index.…”

Section: Primentioning

confidence: 99%

Configuration and Specifications of an Unmanned Aerial Vehicle for Precision Agriculture

Erena¹,

Montesinos

Portillo³

et al. 2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Unmanned Aerial Vehicles (UAVs) with multispectral sensors are increasingly attractive in geosciences for data capture and map updating at high spatial and temporal resolutions. These autonomously-flying systems can be equipped with different sensors, such as a six-band multispectral camera (Tetracam mini-MCA-6), GPS Ublox M8N, and MEMS gyroscopes, and miniaturized sensor systems for navigation, positioning, and mapping purposes. These systems can be used for data collection in precision viticulture. In this study, the efficiency of a light UAV system for data collection, processing, and map updating in small areas is evaluated, generating correlations between classification maps derived from remote sensing and production maps. Based on the comparison of the indices derived from UAVs incorporating infrared sensors with those obtained by satellites (Sentinel 2A and Landsat 8), UAVs show promise for the characterization of vineyard plots with high spatial variability, despite the low vegetative coverage of these crops. Consequently, a procedure for zoning map production based on UAV/UV images could provide important information for farmers.

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Simple reflectance indices track heat and water stress-induced changes in steady-state chlorophyll fluorescence at the canopy scale

Cited by 275 publications

References 49 publications

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

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

Application of fluorescence spectrum to precisely inverse paddy rice nitrogen content

Configuration and Specifications of an Unmanned Aerial Vehicle for Precision Agriculture

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