scholarly journals Nocturnal Light Emitting Diode Induced Fluorescence (LEDIF): A new technique to measure the chlorophyll a fluorescence emission spectral distribution of plant canopies in situ

2019 ◽  
Vol 231 ◽  
pp. 111137 ◽  
Author(s):  
Jon Atherton ◽  
Weiwei Liu ◽  
Albert Porcar-Castell
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Spectral Distribution ◽  
Light Emitting Diode ◽  
Fluorescence Emission ◽  
New Technique ◽  
Light Emitting ◽  
Plant Canopies ◽  
A New Technique

In situ study of photoinhibition of photosynthesis and xanthophyll cycle activity in plants growing in natural gaps of the tropical forest

1998 ◽  
Vol 25 (2) ◽  
pp. 189 ◽  
Author(s):  
A. Thiele ◽  
G.H. Krause ◽  
K. Winter
Keyword(s):  
Chlorophyll A ◽  
Xanthophyll Cycle ◽  
Fluorescence Emission ◽  
D1 Protein ◽  
Barro Colorado Island ◽  
Slow Phase ◽  
Photoinhibition Of Photosynthesis ◽  
Total Carotenoids ◽  
Lowland Forest

Photoinhibition of photosynthesis was studied in situ in leaves of several species of plants growing in natural treefall gaps of a tropical lowland forest (Barro Colorado Island, Panama). Leaves showed several features typical of sun-acclimation: relatively high pools of total carotenoids and xanthophyll cycle pigments and high ratios of chlorophyll a to b. During 1–2 h periods of exposure to direct mid-day sun, all leaves experienced substantial photoinhibition as indicated by a marked decline in the ratio of variable to maximum chlorophyll a fluorescence emission, FV/FM, detected after 10 min of dark adaptation. After return to shade, these ‘dark-adapted’ FV/FM ratios increased with biphasic kinetics, similar to previous findings under controlled conditions in the laboratory. A phase lasting about 1 h accounted for most of the recovery of FV/FM and was followed by a slow phase which proceeded until sunset. The decline in FV/FM during photoinhibition and the fast phase of recovery correlated closely with the amounts of zeaxanthin in the leaves. Given the small portion of the second recovery phase which has previously been attributed to turnover of the D1 protein in Photosystem II, high xanthophyll cycle activity in these gap leaves is probably responsible for the major part of photoinhibition, providing an efficient energy dissipation pathway during periods of high sunlight exposure.

scholarly journals SENSITIVITY TO ENVIRONMENTAL STRESS OF PRATA,JAPIRA AND VITÓRIA BANANA CULTIVARS PROVEN BY CHLOROPHYLL a FLUORESCENCE

2017 ◽  
Vol 39 (2) ◽  
Author(s):  
PRISCILA NOBRES DOS SANTOS ◽  
DIOLINA MOURA SILVA ◽  
CAMILLA ZANOTTI GALLON ◽  
JOSÉ AIRES VENTURA
Keyword(s):  
Environmental Stress ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Physiological Responses ◽  
Fluorescence Emission ◽  
Conservation Of Energy ◽  
Post Harvest ◽  
Mda Content ◽  
Two Stages

ABSTRACT This study aimed to evaluate the physiological responses to environmental stress during pre- and post-harvest of the following banana cultivars: Prata (AAB), Japira (AAAB) and Vitoria (AAAB). Analyses were carried out on young plants at vegetative stage (daughter-plant) and adult plants at reproductive stage (motherplant). The experimental design was completely randomized. In the in vivo pre-harvest analysis were used seven replications, in a factorial scheme (3x2x2), three cultivars and two stages (vegetative and reproductive) and two collection periods (March and June). For the analysis of post-harvest quality were used five replications in a factorial design (3x2x5), corresponding to three cultivars, two development stages and five periods of post-harvest analysis, carried out every two days from stage 4 of fruit ripening. The chlorophyll a fluorescence emission kinetics showed low photochemical performance of the three cultivars in June, a period characterized by lower temperatures and water deficit. Prata was the cultivar with the lowest tolerance to abiotic physiological behavior changes, which also reflected in fruit quality, because there was a change in physical and physicochemical parameters. Japira and Vitoria cultivars showed similar physiological responses in the pre- and post-harvest periods, according to their phylogenetic proximity. The total performance index, i.e., the conservation of energy absorbed by PSII up to the reduction of the final PSI acceptors (PItotal) and the di-malonic aldehyde (MDA) content were significantly higher in Japira and Vitoria cultivars compared to Prata cultivar in the reproductive phase. There was no significant change in the potential quantum efficiency of PSII (FV / FM = jP0) among the three cultivars. It was concluded that Japira and Vitoria cultivars showed greater plasticity to tolerate or even adapt to abiotic variations keeping higher fruit yield. PItotal is the most sensitive parameter during the banana life cycle and important tool for distinguishing different cultivars yields.

A new technique for in-situ measurements of bubble characteristics in bubble columns operated in the heterogeneous regime

2016 ◽  
Vol 155 ◽  
pp. 504-523 ◽  
Author(s):  
P. Maximiano Raimundo ◽  
A. Cartellier ◽  
D. Beneventi ◽  
A. Forret ◽  
F. Augier
Keyword(s):  
In Situ Measurements ◽  
Bubble Columns ◽  
New Technique ◽  
A New Technique ◽  
Bubble Characteristics

Reduction of Reflected Light On Fluorescence Emission for Indocyanine Green

2021 ◽  
Author(s):  
So Yoon Kwon ◽  
Ki-Cheol Yoon ◽  
Kwang Gi Kim
Keyword(s):  
Blood Vessel ◽  
Indocyanine Green ◽  
Blood Vessels ◽  
Light Emitting Diode ◽  
Polarized Light ◽  
Fluorescence Emission ◽  
Light Reflection ◽  
Light Emitting ◽  
Surgical Microscope ◽  
Reflected Light

Abstract Inside the brain tumor, the blood vessels are intricately composed, and the tumors and blood vessels are similar in color. Therefore, when observing tumors and blood vessels with the naked eye or a surgical microscope, it is difficult to distinguish between tumors and blood vessels. Fluorescence staining with indocyanine green (ICG) is performed to distinguish between brain tumors and blood vessels using a surgical microscope. However, when observing the blood circulation state of a tumor or blood vessel through a surgical microscope, light reflection occurs from the camera. In the process of observing the state of the blood vessel, due to the occurrence of light reflection, an obstruction phenomenon in which the observation field is blocked by the blood vessel of the object to be observed occurs. Therefore, it is difficult to diagnose the vascular condition. In this experiment, the 780nm light-emitting diode (LED) was irradiated to the ICG phantom, and then, when the fluorescence expression image was observed, the polarizing filter such as circular polarized light (CPL) filter and linear polarized light (LPL) filter were inserted into the camera and the reflected light was reduced. Therefore, it is possible to reduce the reflected light from the fluorescence expression image by using a polarizing filter, and it is expected to be applicable to surgery and diagnostic fields of cancer such as surgery.

Embedded growth of colorful CsPbX3 (X = Cl, Br, I) nanocrystals in metal−organic frameworks at Room Temperature

2022 ◽  
Author(s):  
Chen Chen ◽  
Lei Nie ◽  
Yizhe Huang ◽  
Shuang Xi ◽  
Xingyue Liu ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Metal Organic Framework ◽  
Light Emitting ◽  
Confined Growth ◽  
Wide Color Gamut ◽  
Metal Organic ◽  
Interfacial Synthesis ◽  
Novel Strategy ◽  
Lead Halide

Abstract Herein, we develop a novel strategy for preparing all-inorganic cesium lead halide (CsPbX3, X= Cl, Br, I) perovskite nanocrystals (NCs)@Zn-based metal-organic framework (MOF) composites through interfacial synthesis. The successful embedding of fluorescent perovskite NCs in Zn-MOFs is due to the in-situ confined growth, which is attributed to the re-nucleation of water-triggered phase transformation from Cs4PbBr6 to CsPbBr3. The controllable synthesis of mixed-halide based composites with various emission wavelength can be achieved by adding the desired amount of halide (Cl or I) salts in the re-nucleation process. More importantly, the anion exchange reaction is inhibited among various composites with different halogen atoms by being trapped in MOFs. Besides, a white light-emitting diode (WLED) is produced using a blue LED chip with the green-emitting and red-emitting composites, which has a color coordinate of (0.3291, 0.3272) and a wide color gamut. This work provides a novel route to achieving perovskite NCs growth in MOFs, which also can be extended to the other NCs embedded in frames as well.

A Compact Microcontrolled Microfluidic System for Photometric Determination of Phosphate in Natural Water Samples

2015 ◽  
Vol 68 (7) ◽  
pp. 1108 ◽  
Author(s):  
Osmundo Dantas Pessoa-Neto ◽  
Tiago Almeida Silva ◽  
Vagner Bezerra dos Santos ◽  
Orlando Fatibello-Filho
Keyword(s):  
Light Emitting Diode ◽  
Flow Analysis ◽  
Photometric Determination ◽  
Microfluidic System ◽  
Experimental Conditions ◽  
Light Emitting ◽  
Experimental Parameters ◽  
Led Photometer

A compact environmentally friendly microcontrolled microfluidic device ideal for in situ phosphate determination was developed based on a microsystem based on low-temperature co-fired ceramics (LTCC) coupled to a light-emitting diode (LED)–photometer with a multicommutation flow analysis (MCFA) approach. The experimental parameters of the MCFA analyzer were optimized by chemometric studies. Under the best experimental conditions, limits of detection and quantification of 0.02 mg P L–1 and 0.07 mg P L–1, respectively, and a sampling frequency of 67 h–1 were estimated. Moreover, a low sample consumption of only 60 μL per determination was the other advantage that fully meets the requirements of sustainable research and green chemistry purposes.

In Situ NMRObservations of the Photolysis of Cymantrene and Methylcymantrene in Supercritical Fluids:  A New Technique Using High-Pressure NMR

1997 ◽  
Vol 119 (42) ◽  
pp. 10170-10177 ◽  
Author(s):  
John C. Linehan ◽  
Scott L. Wallen ◽  
Clement R. Yonker ◽  
Thomas E. Bitterwolf ◽  
J. Timothy Bays
Keyword(s):  
High Pressure ◽  
Supercritical Fluids ◽  
New Technique ◽  
A New Technique
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