Eicosapentaenoic acid content of Skeletonema costatum as a function of growth and irradiance; relation with chlorophyll a content and photosynthetic capacity

1996 ◽  
Vol 196 (1-2) ◽  
pp. 177-188 ◽  
Author(s):  
Alice Blanchemain ◽  
Dominique Grizeau
Keyword(s):  
Eicosapentaenoic Acid ◽  
Chlorophyll A ◽  
Acid Content ◽  
Photosynthetic Capacity ◽  
Skeletonema Costatum ◽  
Chlorophyll A Content

Characterization of diurnal photosynthetic rhythms in the marine diatom Skeletonema costatum grown in synchronous culture under ambient and elevated CO2

2004 ◽  
Vol 31 (4) ◽  
pp. 399 ◽  
Author(s):  
Xiongwen Chen ◽  
Kunshan Gao
Keyword(s):  
Chlorophyll A ◽  
Elevated Co2 ◽  
Skeletonema Costatum ◽  
Co2 Enrichment ◽  
Light Period ◽  
Marine Diatom ◽  
Initial Slope ◽  
Co2 Uptake ◽  
Chlorophyll A Content ◽  
Ambient Co2

Photosynthetic performance was examined in Skeletonema costatum (Greville) Cleve. under 12 : 12-h light : dark (LD) cycle at ambient CO2 (350 μL L–1) and elevated CO2 (1000 μL L–1). At ambient CO2, the cellular chlorophyll a content, the light-saturated photosynthetic rate (Pm), the initial slope of the light saturation curves (α), the photochemical efficiency of PSII (Fv / Fm), the apparent carboxylating efficiency (ACE) and the photosynthetic affinity for CO2 [1 / Km(CO2)] all showed rhythmical changes with different amplitudes during the light period. The Pm had similar changing pattern in the light period with the ACE and 1 / Km(CO2) rather than with the α and Fv / Fm, indicating that rhythmical changes of photosynthetic capacity may be mainly controlled by the activity of C-reduction associated with CO2 uptake during the light period. The CO2 enrichment reduced the ACE and the affinity to CO2, and increased the α, cellular chlorophyll a content and Pm based on cell number. By contrast, the changing patterns of all photosynthetic parameters examined here during the light period had almost the same for cells grown at ambient CO2 and elevated CO2, suggesting that the photosynthetic rhythms of S. costatum are not affected by CO2 enrichment.

Modeling of photosynthesis light curves by linear splines

2019 ◽  
pp. 20-29
Author(s):  
Alexander S. Lelekov ◽  
Rudolf P. Trenkenshu
Keyword(s):  
Experimental Data ◽  
Chlorophyll A ◽  
Skeletonema Costatum ◽  
Light Flux ◽  
Photosynthesis Rate ◽  
Light Curves ◽  
External Irradiation ◽  
Exchange Reactions ◽  
Cell Adaptation ◽  
Linear Splines

The paper presents an example of the linear splines use to describe the photosynthesis light curves for microalgae culture. The main mathematical models of the relationship between photosynthesis rate and light are listed. Based on the previously formulated basic principles of modeling microalgae photobiosynthesis, a mathematical model is proposed that describes the dependence of the assimilation number of chlorophyll a on the value of the light flux by linear splines. The advantage of the proposed approach is a clear definition of the point of change of the limiting factor. It is shown that light-limited photosynthesis rate is determined not only by external irradiation, but also by the concentration of chlorophyll a. The light-saturated rate depends on the amount of a key enzyme complex, which limits the rate of energy exchange reactions in the cell. Verification of the proposed model on the example of the diatom microalgae Skeletonema costatum was carried out. It is shown that the higher the degree of cell adaptation to high irradiation, the better the photosynthesis curve is described by linear splines. If S. costatum cells are adapted to low irradiation, deviations of experimental data from the idealized broken line are observed, which are caused by changes in the pigment composition. When the experimental data are normalized, the cell adaptation factor is reduced, all points are described by a single broken line, which indicates the universality of the proposed approach.

Effect of growth rate on the eicosapentaenoic acid and docosahexaenoic acid content of Isochrysis galbana in chemostat culture

1994 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
E. Molina Grima ◽  
J. A. S�nchez P�rez ◽  
F. Garc�a Camacho ◽  
J. M. Fern�ndez Sevilla ◽  
F. G. Aci�n Fern�ndez
Keyword(s):  
Growth Rate ◽  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Acid Content ◽  
Chemostat Culture ◽  
Isochrysis Galbana

On the Question of the Chlorophyll a Content of the Photosystem II Reaction Center

1994 ◽  
Vol 98 (31) ◽  
pp. 7725-7735 ◽  
Author(s):  
H.-C. Chang ◽  
R. Jankowiak ◽  
N. R. S. Reddy ◽  
C. F. Yocum ◽  
R. Picorel ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Reaction Center ◽  
Chlorophyll A Content

scholarly journals The Epiphytic FernElaphoglossum luridum(Fée) Christ. (Dryopteridaceae) from Central and South America: Morphological and Physiological Responses to Water Stress

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Bruno Degaspari Minardi ◽  
Ana Paula Lorenzen Voytena ◽  
Marisa Santos ◽  
Áurea Maria Randi
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Tca Cycle ◽  
Photosynthetic Parameters ◽  
Relative Water ◽  
Physiological Studies ◽  
Cycle Regulation ◽  
Epiphytic Fern ◽  
Chlorophyll A Content

Elaphoglossum luridum(Fée) Christ. (Dryopteridaceae) is an epiphytic fern of the Atlantic Forest (Brazil). Anatomical and physiological studies were conducted to understand how this plant responds to water stress. TheE. luridumfrond is coriaceus and succulent, presenting trichomes, relatively thick cuticle, and sinuous cell walls in both abaxial and adaxial epidermis. Three treatments were analyzed: control, water deficit, and abscisic acid (ABA). Physiological studies were conducted through analysis of relative water content (RWC), photosynthetic pigments, chlorophyll a fluorescence, and malate content. No changes in RWC were observed among treatments; however, significant decreases in chlorophyll a content and photosynthetic parameters, including optimal irradiance (Iopt) and maximum electron transport rate (ETRmax), were determined by rapid light curves (RLC). No evidence of crassulacean acid metabolism (CAM) pathway was observed inE. luridumin response to either water deficit or exogenous application of ABA. On the other hand, malate content decreased in theE. luridumfrond after ABA treatment, seeming to downregulate malate metabolism at night, possibly through tricarboxylic acid (TCA) cycle regulation.

scholarly journals GROWTH AND FATTY ACID COMPOSITION OF MARINE MICROALGA NANNOCHLOROPSIS sp IN MEDIUM ENRICHED WITH MAGNESIUM

2016 ◽  
Vol 11 (3) ◽  
pp. 409
Author(s):  
J. Tri Astuti ◽  
Lies Sriwuryandari ◽  
Ekoputro Agung Putro ◽  
T. Sembiring
Keyword(s):  
Fatty Acid ◽  
Chlorophyll A ◽  
Growth Period ◽  
High Productivity ◽  
Marine Microalga ◽  
Batch System ◽  
Total Fatty Acids ◽  
Chlorophyll A Content ◽  
Dry Cell ◽  
All Treatment

Micro-algae are to be an attractive way to produce bio-diesel due to high photosynthetic yields and lipid accumulation in cells. This high productivity combined with possibility to uptake CO2 stimulated its utilization as a biological mitigation method of CO2, at once as an alternative renewable source of energy. Growth characteristics and chemical composition of micro-algae can be altered by culture environment. Nutrient sufficiency,included magnesium element (Mg2+) is important factors on overall biochemical composition. In study, Nannochloropsis sp was cultivated in Erlenmeyer 250 ml containing 200 ml f/2 medium. There are three groups of treatment with different levelof magnesium (Mg2+), i.e. 0 (M0); 0.1mgL-1 (M1); and 1.0 mgL-1 (M2). All treatment was designed triplicate in batch system. Culture was then aerated continuously with sterile atmospheric air (1.5 L.min-1). Cells were harvested on 25th day after inoculation and analyzed. Data showed that Chlorophyll-a increased linearly with time and maximum at 18th days of growth period, i.e. 23.57; 26.44; and 27.74mgL-1, for M0; M1; and M2,respectively. Chlorophyll-a content decreased significantly when pH dropped to 5-6.Enrichment with Mg2+ increased the chlorophyll-a content 12.2-17.7%. Dry cell reached 375-400mgL-1 in all treatment. Lipid content of Nannochloropsis sp in control (M0) is 55.3%, higher than M1 and M2. Saturated fatty acid tends to increase from 80.70 (M0)to 96.70 (M1) and 94.53% (M2). Fatty acid of M0 and M1 was composed dominantly by palmitic acid (C16:0), i.e. 49.19-70.75% total fatty acids. Meanwhile, M2 treatment was dominantly by lauric acid (C12:0), i.e. 32.98%.Keywords: CO2 biological mitigation, chlorophyll-a, fatty acid, lipid, agnesium,microalgae, Nannochloropsis sp, photosynthesis.

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