Oxygen evolution rate in Antarctic filamentous alga Stigeoclonium sp. evaluated by optodes relates to chlorophyll fluorescence parameters (Short Communication)

2018 ◽  
Vol 8 (1) ◽  
pp. 143-150
Author(s):  
Peter Váczi
Keyword(s):  
Chlorophyll Fluorescence ◽  
Linear Relationship ◽  
Oxygen Evolution ◽  
Photosynthetically Active Radiation ◽  
Filamentous Alga ◽  
Evolution Rate ◽  
O2 Evolution ◽  
Effective Quantum Yield ◽  
Active Radiation ◽  
Oxygen Evolution Rate

Photosynthetic reactions of algal communities, the essential component of primary production in polar regions, are strongly dependent on environmental factors. Among them, availability and amount of light in particular parts of growing season are of major importance. In this paper, the response of the photosynthetic processes of a filamentous fresh-water alga to photosynthetically active radiation (PAR) was studied by two approaches. The simultaneous measurements of the effective quantum yield (FPSII) and oxygen evolution rate (OER) at stepwise increasing photosynthetically active radiation provided data for beneficial correlation analysis of the FPSII to OER relationship in a wide range of PAR. In this study, the culture of filamentous alga Stigeoclonium sp. was analyzed. The linear relationship between FPSII and OER was found for the low PAR (the range of 0 – 200 mmol.m-2.s-1). At high PAR levels (200 – 1000 mmol.m-2.s-1) another linear relationship with different slope was found. The approach combining the fluorometric and oxymetric method might be used for calibration of data in follow up studies and, consequently for evaluation of photosynthetic rates (O2 evolution) from chlorophyll fluorescence data.

Oxygen evolution rate of rice cultivars

2008 ◽  
Vol 46 (1) ◽  
pp. 148-150 ◽  
Author(s):  
M. A. Bacarin ◽  
A. R. Falqueto ◽  
J. L. Coimbra ◽  
A. C. Oliveira ◽  
A. M. De Magalhaes
Keyword(s):  
Oxygen Evolution ◽  
Evolution Rate ◽  
Rice Cultivars ◽  
Oxygen Evolution Rate

Physiological performance of a foliose macrolichen Umbilicaria antarctica as affected by supplemental UV-B treatment

2015 ◽  
Vol 5 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Mariana Gonzalez Medina ◽  
Roxana Avalos-Chacon
Keyword(s):  
Chlorophyll Fluorescence ◽  
High Resistance ◽  
Photosynthetically Active Radiation ◽  
High Intensity ◽  
Photosynthetic Efficiency ◽  
Photosynthetic Apparatus ◽  
Ps Ii ◽  
Fluorescence Kinetics ◽  
Active Radiation ◽  
High Doses

To date, a limited knowledge is available about Umbilicaria antarctica responses when it is exposed high doses of UV-B radiation. It is well established that resistance of Antarctic lichens to natural UV-B levels including increased doses during ozone hole period is high, thanks to numerous photoprotective mechanism. Capacity of the photoprotective processes, however, is not well known This study attempts to determine changes on the photosynthetic efficiency and on the synthesis of UV-B absorbing compounds of U. antarctica when exposed to low photosynthetically active radiation and extremely high intensity of UV-B light: 3.0 W m-2, of UV-B for 3 hours, 6 hours and 7 days. During the experiment, chlorophyll fluorescence was measured to evaluate changes in photosynthetic apparatus of intrathalline alga. After 7 d exposition, amount of UV-B absorbing compounds was evaluated in U. antarctica. Heavy UV-B stress let to an increase in chlorophyll fluorescence kinetics (OJIPs), however, majority of parameters related to functioning of PS II remained unchanged indicating high resistance of U. antarctica to UV-B stress. Potential (FV/FM) and actual (ФPSII) yields of PS II were not affected by the UV-B treatment as well. In majority of cases, heavy UV-B treatment led to a decrease in the amount of UV-B absorbing compounds extracted from treated thalli.

Tuning Hole Accumulation of Metal Oxides Promotes the Oxygen Evolution Rate

ACS Catalysis ◽  
2020 ◽  
Vol 10 (18) ◽  
pp. 10427-10435
Author(s):  
Peikun Zhang ◽  
Wei Wang ◽  
Hui Wang ◽  
Yanbo Li ◽  
Chunhua Cui
Keyword(s):  
Metal Oxides ◽  
Oxygen Evolution ◽  
Evolution Rate ◽  
Oxygen Evolution Rate

scholarly journals Plant Fluorescence Measured under Two Extreme Lighting Conditions Using a Passive Spectroradiometer

2017 ◽  
Author(s):  
Trina Merrick ◽  
Ralf Bennartz ◽  
Maria Luisa S. P. Jorge ◽  
Thiago S. F. Silva ◽  
John Rausch ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetically Active Radiation ◽  
Light Emitting Diode ◽  
Fluorescence Yield ◽  
Spectral Measurements ◽  
Light Emitting ◽  
Active Radiation ◽  
Lighting Conditions ◽  
Margin Of Error ◽  
Absorbed Photosynthetically Active Radiation

In this study, we evaluated chlorophyll fluorescence (CF) under two extreme illumination conditions at plant scale with a passive spectroradiometer. Fluorescence (F) was estimated by reading directly from radiance spectra of a variety of plants illuminated with light-emitting diode (LED) grow lights in the laboratory. Solar-induced fluorescence (SIF) was estimated from spectral measurements of the same plants under sunlight using the Fraunhofer Line Depth (FLD) method. Chlorophyll fluorescence yield (Fyield) and solar-induced fluorescence yield (SIFyield) were calculated by normalizing F and SIF with absorbed photosynthetically active radiation (APAR). Two approaches to estimating APAR were compared: utilizing white reference spectra and reflected spectra versus white reference spectra combined with the fraction of absorbed photosynthetically active radiation (fPAR) derived from literature. Average F and SIF were different by a factor of approximately twenty-four (F = 0.110 ± 0.038 Wm−2μm−1sr−1 versus SIF = 2.60 ± 1.87 Wm−2μm−1sr−1). In contrast, the average normalized values Fyield and SIFyield were within the margin of error of one another (Fyield = 0.022 ± 0.008 μm−1sr−1 and SIFyield = 0.030 ± 0.020 μm−1sr−1). This study highlights the influence of APAR on CF and the importance of properly accounting for it when estimating yield and demonstrates the ability of two simple and portable experimental setups with a passive instrument to obtain fluorescence metrics.

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