996 results match your criteria leaf reflectance

Foliar optical traits capture physiological and phenological leaf plasticity in Tilia×euchlora in the urban environment.

Sci Total Environ 2021 Sep 11;805:150219. Epub 2021 Sep 11.

Department of Earth and Environmental Sciences, KU Leuven, 3001 Heverlee, Belgium. Electronic address:

Knowledge on the response of trees to the urban heat island (UHI) effect and soil sealing is currently limited, yet of vital importance in an era characterized by both climate change and urbanization. We investigated the physiological and phenological leaf plasticity of Tilia×euchlora trees to the UHI effect and soil sealing and explored the potential of leaf optical traits to quantify the magnitude of leaf plasticity. Temporal changes of leaf water content (LWC), specific leaf area (SLA), total chlorophyll (Chl) and carotenoids (Car) content, Car:Chl ratio and leaf reflectance for 46 Tilia×euchlora trees were measured along a soil sealing and urbanization gradient. Read More

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September 2021

Altered albedo dominates the radiative forcing changes in a subtropical forest following an extreme snow event.

Glob Chang Biol 2021 Sep 15. Epub 2021 Sep 15.

Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, 411008, India.

Subtropical forests are important ecosystems globally due to their extensive role in carbon sequestration. Extreme climate events are known to introduce disturbances in the ecosystem that cause long-term changes in carbon balance and radiation reflectance. However, how these ecosystem function changes contribute to global warming in terms of radiative forcing (RF), especially in the years following a disturbance, still needs to be investigated. Read More

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September 2021

Reading light: Leaf spectra capture fine-scale diversity of closely related, hybridizing arctic shrubs.

New Phytol 2021 Sep 12. Epub 2021 Sep 12.

School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.

●Leaf reflectance spectroscopy is emerging as an effective tool for assessing plant diversity and function. However, the ability of leaf spectra to detect fine-scale plant evolutionary diversity in complicated biological scenarios is not well understood. ●We test if reflectance spectra (400-2400 nm) can distinguish species and detect fine-scale population structure and phylogenetic divergence - estimated from genomic data - in two co-occurring, hybridizing, ecotypically differentiated species of Dryas. Read More

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September 2021

Ground-Based Hyperspectral Remote Sensing for Estimating Water Stress in Tomato Growth in Sandy Loam and Silty Loam Soils.

Sensors (Basel) 2021 Aug 24;21(17). Epub 2021 Aug 24.

College of Water Conservancy and Civil Engineering, South China Agriculture University, Guangzhou 510070, China.

Drought and water scarcity due to global warming, climate change, and social development have been the most death-defying threat to global agriculture production for the optimization of water and food security. Reflectance indices obtained by an Analytical Spectral Device (ASD) Spec 4 hyperspectral spectrometer from tomato growth in two soil texture types exposed to four water stress levels (70-100% FC, 60-70% FC, 50-60% FC, and 40-50% FC) was deployed to schedule irrigation and management of crops' water stress. The treatments were replicated four times in a randomized complete block design (RCBD) in a 2 × 4 factorial experiment. Read More

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Selecting informative bands for partial least squares regressions improves their goodness-of-fits to estimate leaf photosynthetic parameters from hyperspectral data.

Photosynth Res 2021 Sep 7. Epub 2021 Sep 7.

Graduate School of Science and Technology, Shizuoka University, Shizuoka, 422-8529, Japan.

The plant photosynthetic capacity determines the photosynthetic rates of the terrestrial biosphere. Timely approaches to obtain the spatiotemporal variations of the photosynthetic parameters are urgently needed to grasp the gas exchange rhythms of the terrestrial biosphere. While partial least squares regression (PLSR) is a promising way to predict the photosynthetic parameters maximum carboxylation rate (V) and maximum electron transport rate (J) rapidly and non-destructively from hyperspectral data, the approach, however, faces a high risk of overfitting and remains a high hurdle for applications. Read More

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September 2021

Classification of soybean frogeye leaf spot disease using leaf hyperspectral reflectance.

PLoS One 2021 3;16(9):e0257008. Epub 2021 Sep 3.

College of Biological and Agricultural Engineering, Jilin University, Changchun, Jilin, China.

In this study, the feasibility of classifying soybean frogeye leaf spot (FLS) is investigated. Leaf images and hyperspectral reflectance data of healthy and FLS diseased soybean leaves were acquired. First, image processing was used to classify FLS to create a reference for subsequent analysis of hyperspectral data. Read More

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September 2021

Primarily tests of a optoelectronic in-canopy sensor for evaluation of vertical disease infection in cereals.

Pest Manag Sci 2021 Aug 30. Epub 2021 Aug 30.

Department Engineering for Crop Production, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, Germany.

Background: Health scouting of crops by satellite, airplanes, unmanned aerial (UAV) and ground vehicles can only evaluate the crop from above. The visible leaves may show no disease symptoms, but lower, older leaves not visible from above can do. A mobile in-canopy sensor was developed, carried by a tractor to detect diseases in cereal crops. Read More

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Rootstock-Dependent Response of Hass Avocado to Salt Stress.

Plants (Basel) 2021 Aug 13;10(8). Epub 2021 Aug 13.

Gilat Research Center, Agricultural Research Organization, Volcani Institute, M.P. Negev, Gilat 8528000, Israel.

Salt stress is a major limiting factor in avocado () cultivation, exacerbated by global trends towards scarcity of high-quality water for irrigation. Israeli avocado orchards have been irrigated with relatively high-salinity recycled municipal wastewater for over three decades, over which time rootstocks were selected for salt-tolerance. This study's objective was to evaluate the physiological salt response of avocado as a function of the rootstock. Read More

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High-Throughput Phenotyping Approach for the Evaluation of Heat Stress in Korean Ginseng ( Meyer) Using a Hyperspectral Reflectance Image.

Sensors (Basel) 2021 Aug 21;21(16). Epub 2021 Aug 21.

Department of Biosystems Machinery Engineering, College of Agricultural and Life Science, Chungnam National University, Daejeon 34134, Korea.

has been used as a traditional medicine to strengthen human health for centuries. Over the last decade, significant agronomical progress has been made in the development of elite ginseng cultivars, increasing their production and quality. However, as one of the significant environmental factors, heat stress remains a challenge and poses a significant threat to ginseng plants' growth and sustainable production. Read More

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Wool Keratin Hydrolysates for Bioactive Additives Preparation.

Materials (Basel) 2021 Aug 20;14(16). Epub 2021 Aug 20.

Horia Hulubei National Institute of Research and Development for Physics and Nuclear Engineering, 30 Reactorului Str., 077125 Magurele, Romania.

The aim of this paper was to select keratin hydrolysate with bioactive properties by using the enzymatic hydrolysis of wool. Different proteolytic enzymes such as Protamex, Esperase, and Valkerase were used to break keratin molecules in light of bioactive additive preparation. The enzymatic keratin hydrolysates were assessed in terms of the physico-chemical characteristics related to the content of dry substance, total nitrogen, keratin, ash, cysteic sulphur, and cysteine. Read More

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Evaluation of Light-Dependent Photosynthetic Reactions in Houtt. Leaves Grown at Different Light Conditions.

Front Plant Sci 2021 4;12:612702. Epub 2021 Aug 4.

Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.

The Japanese knotweed ( Houtt.) is considered as one of the most aggressive and highly successful invasive plants with a negative impact on invaded habitats. Its uncontrolled expansion became a significant threat to the native species throughout Europe. Read More

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A random forest model for the classification of wheat and rye leaf rust symptoms based on pure spectra at leaf scale.

J Photochem Photobiol B 2021 Aug 8;223:112278. Epub 2021 Aug 8.

Poznań University of Life Sciences, Poznań, Poland.

The pure spectra acquisition of plant disease symptoms is essential to improving the reliability of remote sensing methods in crop protection. The reflectance values read from the pure spectra can be used as valuable training data for development of algorithms designed for plant disease detection at leaf and canopy scale. The aim of this paper is to identify and distinguish spectrally the leaf rust symptoms caused by two closely related special forms (f. Read More

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Remote estimation of leaf area index (LAI) with unmanned aerial vehicle (UAV) imaging for different rice cultivars throughout the entire growing season.

Plant Methods 2021 Aug 10;17(1):88. Epub 2021 Aug 10.

School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, China.

Background: Rice is one of the most important grain crops worldwide. The accurate and dynamic monitoring of Leaf Area Index (LAI) provides important information to evaluate rice growth and production.

Methods: This study explores a simple method to remotely estimate LAI with Unmanned Aerial Vehicle (UAV) imaging for a variety of rice cultivars throughout the entire growing season. Read More

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Canopy reflectance models illustrate varying NDVI responses to change in high latitude ecosystems.

Ecol Appl 2021 Aug 9:e02435. Epub 2021 Aug 9.

Department of Biological Sciences and the Environmental Science and Engineering Program, University of Texas at El Paso, El Paso, Texas, 79968, USA.

Multiyear trends in Normalized Difference Vegetation Index (NDVI) have been used as metrics of high latitude ecosystem change based on the assumption that NDVI change is associated with ecological change, generally as changes in green vegetation amount (green leaf area index [LAI] or plant cover). Further, no change in NDVI is often interpreted as no change in these variables. Three canopy reflectance models including linear mixture model, the SAIL (Scattering from Arbitrarily Inclined Leaves) model, and the GeoSail model were used to simulate scenarios representing high latitude landscape NDVI responses to changes in LAI and plant cover. Read More

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"Wax On, Wax Off": In Vivo Imaging of Plant Physiology and Disease with Fourier Transform Infrared Reflectance Microspectroscopy.

Adv Sci (Weinh) 2021 Aug 2:e2101902. Epub 2021 Aug 2.

School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, 6102, Australia.

Analysis of the epicuticular wax layer on the surface of plant leaves can provide a unique window into plant physiology and responses to environmental stimuli. Well-established analytical methodologies can quantify epicuticular wax composition, yet few methods are capable of imaging wax distribution in situ or in vivo. Here, the first report of Fourier transform infrared (FTIR) reflectance spectroscopic imaging as a non-destructive, in situ, method to investigate variation in epicuticular wax distribution at 25 µm spatial resolution is presented. Read More

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A novel approach for long-term spectral monitoring of desert shrubs affected by an oil spill.

Environ Pollut 2021 Jul 17;289:117788. Epub 2021 Jul 17.

French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel. Electronic address:

Crude oil pollution is a global environmental concern since it persists in the environment longer than most conventional carbon sources. In December 2014, the hyper-arid Evrona Nature Reserve, Israel, experienced large-scale contamination when crude oil spilled. The overarching goal of the study was to investigate the possible changes, caused by an accidental crude oil spill, in the leaf reflectance and biochemical composition of four natural habitat desert shrubs. Read More

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An insight into spectral composition of light available for photosynthesis via remotely assessed absorption coefficient at leaf and canopy levels.

Photosynth Res 2021 Jul 28. Epub 2021 Jul 28.

Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan.

Non-invasive comparative analysis of the spectral composition of energy absorbed by crop species at leaf and plant levels was carried out using the absorption coefficient retrieved from leaf and plant reflectance as an informative metric. In leaves of three species with contrasting leaf structures and photosynthetic pathways (maize, soybean, and rice), the blue, green, and red fractions of leaf absorption coefficients were 48, 20, and 32%, respectively. The fraction of green light in the total budget of light absorbed at the plant level was higher than at the leaf level approaching the size of the red fraction (24% green vs. Read More

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Frequency of processed kaolin application to prevent Diaphorina citri infestation and dispersal in flushing citrus orchards.

Pest Manag Sci 2021 Jul 27. Epub 2021 Jul 27.

School of Philosophy, Sciences and Languages of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.

Background: Processed kaolin is a promising tactic that can be utilized for managing Diaphorina citri Kuwayama infestation. However, the frequency of kaolin application to protect citrus trees during flushing remains undetermined. The objective of this study was to ascertain the frequency of kaolin application (2%) required to reduce D. Read More

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Detection of apple proliferation disease in Malus × domestica by near infrared reflectance analysis of leaves.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Dec 13;263:120178. Epub 2021 Jul 13.

Laimburg Research Centre, Laimburg 6, Pfatten (Vadena), IT-39040 Auer (Ora), South Tyrol, Italy. Electronic address:

In this study near infrared spectroscopical analysis of dried and ground leaves was performed and combined with a multivariate data analysis to distinguish 'Candidatus Phytoplasma mali' infected from non-infected apple trees (Malus × domestica). The bacterium is the causative agent of Apple Proliferation, one of the most threatening diseases in commercial apple growing regions. In a two-year study, leaves were sampled from three apple orchards, at different sampling events throughout the vegetation period. Read More

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December 2021

How trees thrive in a dry climate: Diurnal and seasonal hydrology and water relations in a riparian cottonwood grove.

Tree Physiol 2021 Jul 14. Epub 2021 Jul 14.

Department of Biological Sciences, University of Lethbridge, 4401 University Drive W., Lethbridge, Alberta T1K 3M4, Canada.

In semi-arid ecoregions trees are restricted to river valley floodplains where river water supplements the limited precipitation. To characterize the associated diurnal and seasonal dynamics in hydrology and water relations we studied narrowleaf cottonwoods (Populus angustifolia) along a prairie river in Canada. From June through August, the shallow soil moisture was depleted but moisture remained higher above the alluvial groundwater table, which dropped to 2. Read More

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Early infestations by arthropod pests induce unique changes in plant compositional traits and leaf reflectance.

Pest Manag Sci 2021 Jul 13. Epub 2021 Jul 13.

Department of Entomology and Nematology, University of California Davis, Davis, CA, USA.

Background: With steadily growing interest in the use of remote-sensing technologies to detect and diagnose pest infestations in crops, it is important to investigate and characterize possible associations between crop leaf reflectance and unique pest-induced changes in plant compositional traits. Accordingly, we compiled plant compositional traits from chrysanthemum and gerbera plants in four treatments: non-infested, or infested with mites, thrips or whiteflies, and we acquired hyperspectral leaf reflectance data from the same plants over time (0-14 days).

Results: Plant compositional traits changed significantly in response to arthropod infestations, and individual chrysanthemum and gerbera plants were classified with 78% and 80% accuracy, respectively. Read More

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Impact of Varying Light and Dew on Ground Cover Estimates from Active NDVI, RGB, and LiDAR.

Plant Phenomics 2021 27;2021:9842178. Epub 2021 May 27.

CSIRO Agriculture and Food, Canberra, ACT, Australia.

Canopy ground cover (GC) is an important agronomic measure for evaluating crop establishment and early growth. This study evaluates the reliability of GC estimates, in the presence of varying light and dew on leaves, from three different ground-based sensors: (1) normalized difference vegetation index (NDVI) from the commercially available GreenSeeker®; (2) RGB images from a digital camera, where GC was determined as the portion of pixels from each image meeting a greenness criterion (i.e. Read More

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Detection of the Metabolic Response to Drought Stress Using Hyperspectral Reflectance.

J Exp Bot 2021 Jun 3. Epub 2021 Jun 3.

Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA.

Drought is the most important limitation on crop yield. Understanding and detecting drought stress in crops is vital for improving water use efficiency through effective breeding and management. Leaf reflectance spectroscopy offers a rapid, non-destructive alternative to traditional techniques for measuring plant traits involved in a drought response. Read More

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Principal Component Analysis to Determine the Surface Properties That Influence the Self-Cleaning Action of Hydrophobic Plant Leaves.

Langmuir 2021 07 29;37(27):8177-8189. Epub 2021 Jun 29.

Microbiology at Interfaces, Department of Life Sciences, Manchester Metropolitan University, Manchester M15 6BH, U.K.

It is well established that many leaf surfaces display self-cleaning properties. However, an understanding of how the surface properties interact is still not achieved. Consequently, 12 different leaf types were selected for analysis due to their water repellency and self-cleaning properties. Read More

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Contrasting responses of major and minor volatile compounds to warming and gall-infestation in the Arctic willow Salix myrsinites.

Sci Total Environ 2021 Nov 19;793:148516. Epub 2021 Jun 19.

Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark; Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.

Climate change is altering high-latitude ecosystems in multiple facets, including increased insect herbivory pressure and enhanced emissions of volatile organic compounds (VOC) from vegetation. Yet, joint impacts of climatic drivers and insect herbivory on VOC emissions from the Arctic remain largely unknown. We examined how one-month warming by open-top plastic tents, yielding a 3-4 °C air temperature increase, and the natural presence of gall-forming eriophyoid mites, Aculus tetanothrix, individually and in combination, affect VOC emissions from whortle leaved willow, Salix myrsinites, at two elevations in an Arctic heath tundra of Abisko, Northern Sweden. Read More

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November 2021

Spectroscopy outperforms leaf trait relationships for predicting photosynthetic capacity across different forest types.

New Phytol 2021 10 16;232(1):134-147. Epub 2021 Jul 16.

Division for Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China.

Leaf trait relationships are widely used to predict ecosystem function in terrestrial biosphere models (TBMs), in which leaf maximum carboxylation capacity (V ), an important trait for modelling photosynthesis, can be inferred from other easier-to-measure traits. However, whether trait-V relationships are robust across different forest types remains unclear. Here we used measurements of leaf traits, including one morphological trait (leaf mass per area), three biochemical traits (leaf water content, area-based leaf nitrogen content, and leaf chlorophyll content), one physiological trait (V ), as well as leaf reflectance spectra, and explored their relationships within and across three contrasting forest types in China. Read More

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October 2021

A best-practice guide to predicting plant traits from leaf-level hyperspectral data using partial least squares regression.

J Exp Bot 2021 Jun 15. Epub 2021 Jun 15.

Terrestrial Ecosystem Science and Technology Group, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA.

Partial least squares regression (PLSR) modelling is a statistical technique for correlating datasets, and involves the fitting of a linear regression between two matrices. One application of PLSR enables leaf traits to be estimated from hyperspectral optical reflectance data, facilitating rapid, high-throughput, non-destructive plant phenotyping. This technique is of interest and importance in a wide range of contexts including crop breeding and ecosystem monitoring. Read More

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Using Spectral Reflectance to Estimate the Leaf Chlorophyll Content of Maize Inoculated With Arbuscular Mycorrhizal Fungi Under Water Stress.

Front Plant Sci 2021 28;12:646173. Epub 2021 May 28.

College of Forestry, Henan Agricultural University, Zhengzhou, China.

Leaf chlorophyll content is an important indicator of the growth and photosynthesis of maize under water stress. The promotion of maize physiological growth by (AMF) has been studied. However, studies of the effects of AMF on the leaf chlorophyll content of maize under water stress as observed through spectral information are rare. Read More

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Can flowers affect land surface albedo and soil microclimates?

Int J Biometeorol 2021 Jun 12. Epub 2021 Jun 12.

Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark.

The phenology of vegetation, namely leaf-out and senescence, can influence the Earth's climate over regional spatial scales and long time periods (e.g., over 30 years or more), in addition to microclimates over local spatial scales and shorter time periods (weeks to months). Read More

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Author Correction: Mayetiola destructor (Diptera: Cecidomyiidae) host preference and survival on small grains with respect to leaf reflectance and phytohormone concentrations.

Sci Rep 2021 Jun 7;11(1):12361. Epub 2021 Jun 7.

Department of Entomology, Plant Pathology and Nematology, College of Agricultural and Life Sciences, University of Idaho, 875 Perimeter Dr., Moscow, ID, 83843-2329, USA.

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