Reflectance indices as nondestructive indicators of the physiological status of Ceratonia siliqua seedlings under varying moisture and temperature regimes

2012 ◽  
Vol 39 (7) ◽  
pp. 588 ◽  
Author(s):  
Júlio Osório ◽  
Maria Leonor Osório ◽  
Anabela Romano
Keyword(s):  
Water Availability ◽  
Spectral Reflectance ◽  
Water Status ◽  
Chlorophyll Concentration ◽  
Photochemical Efficiency ◽  
Principal Component ◽  
Physiological Status ◽  
Total Chlorophyll ◽  
Ceratonia Siliqua ◽  
Reflectance Indices

We investigated the use of spectral reflectance techniques to monitor the physiological responses of Ceratonia siliqua L. seedlings exposed to different levels of water availability under normal (25 : 18°C, day : night) and elevated (32 : 21°C, day : night) temperatures. Three spectral reflectance indices (photochemical reflectance index, PRI; water index, WI; red edge position, REP) were measured along with water status, chlorophyll fluorescence and chlorophyll concentration variables in the leaves of well watered, moderately stressed, severely stressed and rehydrated plants under each temperature regime. The PSII effective photochemical efficiency (φ2) and the intrinsic efficiency of open PSII centres (F′v/F′m) correlated significantly with PRI, and these three variables loaded heavily onto the same principal component of a three-factor principal component analysis solution. Water concentration (WC) and the succulence index (SI) were more strongly correlated with WI than either water potential (ΨPD) or relative water content (RWC). Accordingly, WI, WC and SI were combined in the second principal component, and ΨPD and RWC in the third. Our results provide clear evidence for interaction between water availability and temperature in the WI and the PRI response segments of the reflectance curves. Elevated temperature inhibited the recovery of WI spectral segments more than that of the PRI segments in SS plants. REP showed a strongly positive linear relationship with leaf total chlorophyll concentration across all water and temperature treatment combinations. PRI, WI and REP are therefore reliable markers that can be used to monitor φ2, WC and total chlorophyll concentration, respectively, in C. siliqua seedlings under drought and temperature stress.

scholarly journals Diazotrophic <i>Trichodesmium</i> impact on UV–Vis radiance and pigment composition in the western tropical South Pacific

2018 ◽  
Vol 15 (16) ◽  
pp. 5249-5269 ◽  
Author(s):  
Cécile Dupouy ◽  
Robert Frouin ◽  
Marc Tedetti ◽  
Morgane Maillard ◽  
Martine Rodier ◽  
...  
Keyword(s):  
High Performance ◽  
New Caledonia ◽  
Chlorophyll Concentration ◽  
Principal Component ◽  
Euphotic Zone ◽  
South Pacific ◽  
Free Fall ◽  
Total Chlorophyll ◽  
Chl A ◽  
Underwater Vision

Abstract. We assessed the influence of the marine diazotrophic cyanobacterium Trichodesmium on the bio-optical properties of western tropical South Pacific (WTSP) waters (18–22∘ S, 160∘ E–160∘ W) during the February–March 2015 OUTPACE cruise. We performed measurements of backscattering and absorption coefficients, irradiance, and radiance in the euphotic zone with a Satlantic MicroPro free-fall profiler and took Underwater Vision Profiler 5 (UPV5) pictures for counting the largest Trichodesmium spp. colonies. Pigment concentrations were determined by fluorimetry and high-performance liquid chromatography and picoplankton abundance by flow cytometry. Trichome concentration was estimated from pigment algorithms and validated by surface visual counts. The abundance of large colonies counted by the UVP5 (maximum 7093 colonies m−3) was well correlated to the trichome concentrations (maximum 2093 trichomes L−1) with an aggregation factor of 600. In the Melanesian archipelago, a maximum of 4715 trichomes L−1 was enumerated in pump samples (3.2 m) at 20∘ S, 167 30∘ E. High Trichodesmium abundance was always associated with absorption peaks of mycosporine-like amino acids (330, 360 nm) and high particulate backscattering, but not with high Chl a fluorescence or blue particulate absorption (440 nm). Along the west-to-east transect, Trichodesmium together with Prochlorococcus represented the major part of total chlorophyll concentration; the contribution of other groups were relatively small or negligible. The Trichodesmium contribution to total chlorophyll concentration was the highest in the Melanesian archipelago around New Caledonia and Vanuatu (60 %), progressively decreased to the vicinity of the islands of Fiji (30 %), and reached a minimum in the South Pacific Gyre where Prochlorococcus dominated chlorophyll concentration. The contribution of Trichodesmium to zeaxanthin was respectively 50, 40 and 20 % for these regions. During the OUTPACE cruise, the relationship between normalized water-leaving radiance (nLw) in the ultraviolet and visible and chlorophyll concentration was similar to that found during the BIOSOPE cruise in the eastern tropical Pacific. Principal component analysis (PCA) of OUTPACE data showed that nLw at 305, 325, 340, 380, 412 and 440 nm was strongly correlated to chlorophyll and zeaxanthin, while nLw at 490 and 565 nm exhibited lower correlations. These results, as well as differences in the PCA of BIOSOPE data, indicated that nLw variability in the greenish blue and yellowish green during OUTPACE was influenced by other variables associated with Trichodesmium presence, such as backscattering coefficient, phycoerythrin fluorescence and/or zeaxanthin absorption, suggesting that Trichodesmium detection should involve examination of nLw in this spectral domain.

scholarly journals Ability of Modified Spectral Reflectance Indices for Estimating Growth and Photosynthetic Efficiency of Wheat under Saline Field Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Salah El-Hendawy ◽  
Nasser Al-Suhaibani ◽  
Yaser Dewir ◽  
Salah Elsayed ◽  
Majed Alotaibi ◽  
...  
Keyword(s):  
Salt Stress ◽  
Spectral Reflectance ◽  
Photosynthetic Efficiency ◽  
Near Infrared ◽  
Field Conditions ◽  
Physiological Status ◽  
Dry Matter Content ◽  
Reflectance Indices ◽  
Non Destructive ◽  
Spectral Reflectance Indices

Hyperspectral sensing offers a quick and non-destructive alternative for assessing phenotypic parameters of plant physiological status and salt stress tolerance. This study compares the performance of published and modified spectral reflectance indices (SRIs) for estimating and predicting the growth and photosynthetic efficiency of two wheat cultivars exposed to three salinity levels (control, 6.0, and 12.0 dS m−1). Results show that individual SRIs based on visible- and near-infrared (VIS/VIS, NIR/VIS, and NIR/NIR) estimate and predict measured parameters considerably more efficiently than those based on shortwave-infrared (SWIR/VIS and SWIR/NIR), with the exception of some modified indices (the water balance index (WABI-1(1550, 482), WABI-2(1640, 482), and WABI-3(1650, 531)), normalized difference moisture index (NDMI(1660, 1742)), and dry matter content index (DMCI(1550, 2305)), which show moderate to strong relationships with measured parameters. Overall results indicate that modified SRIs can serve as rapid and non-destructive high-throughput alternative approaches for tracking growth and photosynthetic efficiency of wheat under salt stress field conditions.

scholarly journals   Arbuscular mycorrhizae improves photosynthesis and water status of Zea mays L. under drought stress

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 186-191 ◽  
Author(s):  
X.C. Zhu ◽  
F.B. Song ◽  
S.Q. Liu ◽  
T.D. Liu ◽  
X. Zhou
Keyword(s):  
Zea Mays ◽  
Drought Stress ◽  
Zea Mays L ◽  
Water Status ◽  
Chlorophyll Concentration ◽  
Photochemical Efficiency ◽  
Fluorescence Maximum ◽  
Psii Photochemistry ◽  
Maize Plants ◽  
Mycorrhizal Plants

The influences of arbuscular mycorrhizal (AM) fungus on growth, gas exchange, chlorophyll concentration, chlorophyll fluorescence and water status of maize (Zea mays L.) plants were studied in pot culture under well-watered and drought stress conditions. The maize plants were grown in a sand and black soil mixture for 4 weeks, and then exposed to drought stress for 4 weeks. Drought stress significantly decreased AM colonization and total dry weight. AM symbioses notably enhanced net photosynthetic rate and transpiration rate, but decreased intercellular CO<sub>2</sub> concentration of maize plants regardless of water treatments. Mycorrhizal plants had higher stomatal conductance than non-mycorrhizal plants under drought stress. The concentrations of chlorophyll were higher in mycorrhizal than non-mycorrhizal plants under drought stress. AM colonization significantly increased maximal fluorescence, maximum quantum efficiency of PSII photochemistry and potential photochemical efficiency, but decreased primary fluorescence under well-watered and droughted conditions. Mycorrhizal maize plants had higher relative water content and water use efficiency under drought stress compared with non-mycorrhizal plants. The results indicated that AM symbiosis alleviates the toxic effect of drought stress via improving photosynthesis and water status of maize plants. &nbsp;

scholarly journals Assemblage of indigenous arbuscular mycorrhizal fungi and green waste compost enhance drought stress tolerance in carob (Ceratonia siliqua L.) trees

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abderrahim Boutasknit ◽  
Marouane Baslam ◽  
Mohamed Ait-El-Mokhtar ◽  
Mohamed Anli ◽  
Raja Ben-Laouane ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Arbuscular Mycorrhizal Fungi ◽  
Oxidative Damage ◽  
Mycorrhizal Fungi ◽  
Water Status ◽  
Soluble Sugar ◽  
Photochemical Efficiency ◽  
Arbuscular Mycorrhizal ◽  
Field Capacity ◽  
Ceratonia Siliqua

AbstractIn the current study, an eco-friendly management technology to improve young carob (Ceratonia siliqua L.) tree tolerance to water deficit was set up by using single or combined treatments of arbuscular mycorrhizal fungi (AMF) and/or compost (C). Two groups of young carob have been installed: (i) carob cultivated under well-watered conditions (WW; 70% field capacity (FC)) and (ii) where the plants were drought-stressed (DS; 35% FC) during 2, 4, 6, and 8 months. The effect of used biofertilizers on the course of growth, physiological (photosynthetic traits, water status, osmolytes, and mineral content), and biochemical (hydrogen peroxide (H2O2), oxidative damage to lipids (malondialdehyde (MDA), and membrane stability (MS)) traits in response to short- and long-term droughts were assessed. The dual application of AMF and C (C + AMF) boosted growth, physiological and biochemical parameters, and nutrient uptake in carob under WW and DS. After eight months, C + AMF significantly enhanced stomatal conductance by 20%, maximum photochemical efficiency of PSII by 7%, leaf water potential by 23%, chlorophyll and carotenoid by 40%, plant uptake of mineral nutrients (P by 75%, N by 46%, K+ by 35%, and Ca2+ by 40%), concentrations of soluble sugar by 40%, and protein content by 44% than controls under DS conditions. Notably, C + AMF reduced the accumulation of H2O2 and MDA content to a greater degree and increased MS. In contrast, enzyme activities (superoxide dismutase, catalase, peroxidase, and polyphenoloxidase) significantly increased in C + AMF plants under DS. Overall, our findings suggest that the pairing of C + AMF can mediate superior drought tolerance in young carob trees by increasing leaf stomatal conductance, cellular water content, higher solute concentration, and defense response against oxidative damage during the prolonged period of DS.

Skin Chromophore Estimation from Mobile Selfie Images using Constrained Independent Component Analysis

2020 ◽  
Vol 2020 (14) ◽  
pp. 357-1-357-6
Author(s):  
Luisa F. Polanía ◽  
Raja Bala ◽  
Ankur Purwar ◽  
Paul Matts ◽  
Martin Maltz
Keyword(s):  
Independent Component Analysis ◽  
Spectral Reflectance ◽  
Source Separation ◽  
Principal Component ◽  
Component Analysis ◽  
Previous Method ◽  
Independent Component ◽  
Light Transport ◽  
Camera Model ◽  
Constrained Independent Component Analysis

Human skin is made up of two primary chromophores: melanin, the pigment in the epidermis giving skin its color; and hemoglobin, the pigment in the red blood cells of the vascular network within the dermis. The relative concentrations of these chromophores provide a vital indicator for skin health and appearance. We present a technique to automatically estimate chromophore maps from RGB images of human faces captured with mobile devices such as smartphones. The ultimate goal is to provide a diagnostic aid for individuals to monitor and improve the quality of their facial skin. A previous method approaches the problem as one of blind source separation, and applies Independent Component Analysis (ICA) in camera RGB space to estimate the chromophores. We extend this technique in two important ways. First we observe that models for light transport in skin call for source separation to be performed in log spectral reflectance coordinates rather than in RGB. Thus we transform camera RGB to a spectral reflectance space prior to applying ICA. This process involves the use of a linear camera model and Principal Component Analysis to represent skin spectral reflectance as a lowdimensional manifold. The camera model requires knowledge of the incident illuminant, which we obtain via a novel technique that uses the human lip as a calibration object. Second, we address an inherent limitation with ICA that the ordering of the separated signals is random and ambiguous. We incorporate a domain-specific prior model for human chromophore spectra as a constraint in solving ICA. Results on a dataset of mobile camera images show high quality and unambiguous recovery of chromophores.

scholarly journals Influence of monometallic and bimetallic phytonanoparticles on physiological status of mezquite

2019 ◽  
Vol 14 (1) ◽  
pp. 62-68 ◽  
Author(s):  
Daniel Gonzalez-Mendoza ◽  
Benjamín Valdez-Salas ◽  
Erick Bernardo-Mazariegos ◽  
Olivia Tzintzun-Camacho ◽  
Federico Gutiérrez-Miceli ◽  
...  
Keyword(s):  
Bimetallic Nanoparticles ◽  
Positive Impact ◽  
Photochemical Efficiency ◽  
Localized Surface Plasmon ◽  
Physiological Status ◽  
Ag Nps ◽  
Zeta Potentials ◽  
Minimum Particle Size ◽  
Ag Particles ◽  
The Impact

AbstractThe present study was conducted to evaluate the impact of monometallic and bimetallic nanoparticles (NPs) of copper (Cu) and silver (Ag) from Justicia spicigera on the photochemical efficiency and phenol pattern of Prosopis glandulosa. In this study, the existence of localized surface plasmon resonance absorption associated with the nano-sized nature of Ag, Cu and Cu/Ag particles was confirmed by the presence of a single peak around 487, 585, and 487/580 nm respectively. Zeta potential and electrophoretic mobility were found to be 0.2 mV and 0.02 μmcm/(Vs) for synthesized NPs indicating less stability and thus tendency to agglomerate, and broad distribution of particles. Cu-NPs and Cu/Ag-NPs demonstrate that the dispersed phase is stable and has a minimum particle size at zeta potentials above –30 mV. Changes in phenolic compounds, total chlorophyll, and photochemical efficiency in leaves exposed to Ag, Cu and Cu/Ag phyto-nanoparticles were evaluated up to 72 hours. The results revealed that Ag-NP and Cu-NP from J. spicigera at 100 mg/L showed significant reduction in chlorophyll, epidermal polyphenol content and photochemical efficiency of P. glandulosa. In contrast, the application of bimetallic Cu/Ag-NP from J. spicigera showed a positive impact on physiological parameters of P. glandulosa after 72 h of exposure.

Sequence comparison and expression analysis of an inferred Na+/Pi cotransporter gene in the marine diatom Skeletonema tropicum

2021 ◽  
Vol 64 (1) ◽  
pp. 71-80
Author(s):  
Shr-Hau Hung ◽  
Yung-Hsiu Lu ◽  
Chih-Ching Chung ◽  
Chi-Yu Shih ◽  
Gwo-Ching Gong ◽  
...  
Keyword(s):  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Higher Plants ◽  
Photochemical Efficiency ◽  
Marine Diatom ◽  
Physiological Status ◽  
Homologous Gene ◽  
Regression Equations ◽  
Sequence Alignments ◽  
Yeast Fungi

Abstract Unicellular algae have evolved to express many forms of high-affinity phosphate transporters, and homologs of these proteins are broadly distributed in yeast, fungi, higher plants, and vertebrates. In this report, an effort has been made to characterize such a transporter gene, StPHO, in the marine diatom Skeletonema tropicum. The primers used for polymerase chain reaction were designed by referring to a homologous gene in a prasinophyte, and the full-length (1692 bp) cDNA of StPHO was then cloned and sequenced. Sequence alignments and secondary structure prediction indicated that StPHO is a gene that encodes a type III Na+/Pi cotransporter (SLC20 family). To study the function of StPHO, specific concentrations of inorganic phosphate (Pi) were used to alter the physiological status of S. tropicum. In each treatment, samples were collected for the measurements of StPHO mRNA, [PO4 3−], cell abundance, the maximal photochemical efficiency of photosystem II (F v /F m ), and alkaline phosphatase activity (APA). The results indicated that the ambient [PO4 3−] strongly affected the population growth and related physiological parameters of S. tropicum. The transcription of StPHO was fully repressed when the [PO4 3−] was greater than 1 μM but increased approximately 100-fold when the ambient [PO4 3−] decreased to 0.02 μM. Within this [PO4 3−] range, the regression equations are Y = −0.6644X + 0.9034 and Y = −0.5908X + 0.8054 for Pi-starved and Pi-limited treatments, respectively. This trend of gene expression suggested that StPHO plays an important role in the uptake of [PO4 3−], and StPHO may serve as a useful molecular biomarker for Pi-stressed diatom populations in marine ecosystems.

Spectral Reflectance Indices as a Potential Indirect Selection Criteria for Wheat Yield under Irrigation

Crop Science ◽  
2006 ◽  
Vol 46 (2) ◽  
pp. 578-588 ◽  
Author(s):  
M. A. Babar ◽  
M. P. Reynolds ◽  
M. van Ginkel ◽  
A. R. Klatt ◽  
W. R. Raun ◽  
...  
Keyword(s):  
Spectral Reflectance ◽  
Selection Criteria ◽  
Wheat Yield ◽  
Indirect Selection ◽  
Reflectance Indices ◽  
Spectral Reflectance Indices
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