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.

scholarly journals Shading Effects on Leaf Gas Exchange, Leaf Pigments and Secondary Metabolites of Polygonum minus Huds., an Aromatic Medicinal Herb

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 608
Author(s):  
Fairuz Fatini Mohd Yusof ◽  
Jamilah Syafawati Yaacob ◽  
Normaniza Osman ◽  
Mohd Hafiz Ibrahim ◽  
Wan Abd Al Qadr Imad Wan-Mohtar ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Secondary Metabolites ◽  
Chlorophyll A ◽  
Leaf Gas Exchange ◽  
Photosynthesis Rate ◽  
Total Phenolic ◽  
Chlorophyll B ◽  
Low Light ◽  
Total Anthocyanin ◽  
Polygonum Minus

The growing demand for high value aromatic herb Polygonum minus-based products have increased in recent years, for its antioxidant, anticancer, antimicrobial, and anti-inflammatory potentials. Although few reports have indicated the chemical profiles and antioxidative effects of Polygonum minus, no study has been conducted to assess the benefits of micro-environmental manipulation (different shading levels) on the growth, leaf gas exchange and secondary metabolites in Polygonum minus. Therefore, two shading levels (50%:T2 and 70%:T3) and one absolute control (0%:T1) were studied under eight weeks and 16 weeks of exposures on Polygonum minus after two weeks. It was found that P. minus under T2 obtained the highest photosynthesis rate (14.892 µmol CO2 m−2 s−1), followed by T3 = T1. The increase in photosynthesis rate was contributed by the enhancement of the leaf pigments content (chlorophyll a and chlorophyll b). This was shown by the positive significant correlations observed between photosynthesis rate with chlorophyll a (r2 = 0.536; p ≤ 0.05) and chlorophyll b (r2 = 0.540; p ≤ 0.05). As the shading levels and time interval increased, the production of total anthocyanin content (TAC) and antioxidant properties of Ferric Reducing Antioxidant Power (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) also increased. The total phenolic content (TPC) and total flavonoid content (TFC) were also significantly enhanced under T2 and T3. The current study suggested that P.minus induce the production of more leaf pigments and secondary metabolites as their special adaptation mechanism under low light condition. Although the biomass was affected under low light, the purpose of conducting the study to boost the bioactive properties in Polygonum minus has been fulfilled by 50% shading under 16 weeks’ exposure.

Interpretation of Activation Volumes for Water Exchange Reactions Revisited: AbInitioCalculations for Al3+, Ga3+, and In3+, and New Experimental Data

1998 ◽  
Vol 120 (26) ◽  
pp. 6569-6577 ◽  
Author(s):  
Th. Kowall ◽  
P. Caravan ◽  
H. Bourgeois ◽  
L. Helm ◽  
F. P. Rotzinger ◽  
...  
Keyword(s):  
Experimental Data ◽  
Water Exchange ◽  
Exchange Reactions

Simulating Radio Element Release and Water-Rock Interactions During Dissolution of Borosilicate Glass

1997 ◽  
Vol 506 ◽  
Author(s):  
A V Chambers ◽  
T G Heath ◽  
C M Linklater ◽  
A M Thompson ◽  
R M Wiggin
Keyword(s):  
Experimental Data ◽  
Borosilicate Glass ◽  
Glass Surface ◽  
Major Elements ◽  
Reaction Products ◽  
Exchange Reactions ◽  
Model Calculations ◽  
Dissolution Behaviour ◽  
Uranium Plutonium ◽  
Good Agreement

ABSTRACTA model has been developed that can simulate in some detail the chemistry of the glass dissolution process. To test the performance of the model, calculations were carried out to predict the dissolution behaviour of a commercial borosilicate glass. The model could reproduce accurately the behaviour of major elements released from the glass, although in the case of silica, ‘sorption’ at the glass surface was required in order to achieve good agreement with experimental data. Secondary reaction products sepiolite, montmorillonite, analcime and goethite were predicted to form. Further calculations were carried out to simulate the release of radioelements (caesium, strontium, uranium, plutonium) from within the dissolving glass. The precipitation of insoluble solids was the only mechanism included in the model to retain the radioelements at the glass surface. For plutonium, there was good agreement between model predictions and available experimental data. For caesium and strontium, the model underestimated the amount of retention at the glass surface and additional retention mechanisms, such as coprecipitation or ion exchange reactions involving newly-formed clay-type minerals at the glass surface must be invoked to explain experimental observation.

Diel Periodicity of Chlorophyll a Concentration in Oregon Coastal Waters

1972 ◽  
Vol 29 (9) ◽  
pp. 1253-1259 ◽  
Author(s):  
Walter A. Glooschenko ◽  
Herbert Curl Jr. ◽  
Lawrence F. Small
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Dark Period ◽  
Skeletonema Costatum ◽  
Time Of Day ◽  
Light Period ◽  
Diel Periodicity ◽  
Low Light ◽  
Chlorophyll Precursor

Concentrations of chlorophyll a in phytoplankton exhibited a diel periodicity in Oregon coastal waters. Maximum surface concentrations often occurred around midnight and highest 25-m concentrations early in the evening (or even in late afternoon). Concentrations at intermediate depths fell in between and in a predictable progression with depth and time of day. Minimum chlorophyll a values occurred in the afternoon. No definite periodicity was established at 50 m.Laboratory studies with Skeletonema costatum demonstrated that the diel cycle of chlorophyll a per cell was related to the light intensity and duration to which cells were exposed. Highest concentrations of this pigment occurred early in the dark period and lowest concentrations in the light period when cells were grown under photoperiods of 9, 12, and 15 hr at a light intensity of approximately 1200 ft-c. Pigment bleaching probably was responsible for the low concentrations during the light period. The decline of chlorophyll a from the maximum early in the dark period began after the cells possibly became deficient in some chlorophyll precursor or energy-yielding substrate. Addition of an external carbon source during the dark period prolonged the high chlorophyll a concentrations in the dark before the decline began. Under low light (400 ft-c) chlorophyll a synthesis occurred only in the light. This phenomenon was most likely due to an insufficient amount of energy-yielding substrate or precursor synthesized during the low-light period, and the lack of bleaching in the light period at this lower intensity. The laboratory results were consistent with interpretations of the field data. A correction for diel pigment periodicity is recommended for models estimating photosynthesis from chlorophyll and light data and for oceanographic surveys during which sampling of chlorophyll a is carried out throughout the 24-hr day.

Quantitative regularities of changes in the relative content of chlorophyll at the joint action of light and temperature in diatoms

2019 ◽  
pp. 28-36 ◽  
Author(s):  
Ilona V. Kovalyova ◽  
Zosim Z. Finenko
Keyword(s):  
Organic Carbon ◽  
Light Intensity ◽  
Skeletonema Costatum ◽  
Light Flux ◽  
High Light Intensity ◽  
Relative Content ◽  
Effect Of Temperature ◽  
Power Relationship ◽  
Specific Content ◽  
Wide Range

According to experimental data for two spеcies of diatoms Phaeodactylum tricornutum and Skeletonema costatum, a mathematical description of the combined effect of light and temperature on the change in the intracellular ratio of organic carbon to chlorophyll a was carried out. The equation allows estimating the relative content of chlorophyll in algae in a wide range of temperature and light conditions. According to the results of calculations, the power relationship between temperature and organic carbon and chlorophyll was determined. The highest values of the relative content of chlorophyll were observed at high light intensity and low temperature, the minimum ones were at high temperature and low light intensity. At high density of the light flux, the effect of temperature on the specific content of chlorophyll in algae is more pronounced than at low irradiance.

Dynamique des populations planctoniques et bactériennes au cours d'une production expérimentale de phytoplancton marin naturel. II. Structure et physiologie des populations et leurs interactions

1980 ◽  
Vol 26 (3) ◽  
pp. 297-307 ◽  
Author(s):  
P. P. Lelong ◽  
M. A. Bianchi ◽  
Y. P. Martin
Keyword(s):  
Chlorophyll A ◽  
Initial Conditions ◽  
Skeletonema Costatum ◽  
Physiological State ◽  
Bacterial Flora ◽  
Algal Species ◽  
Shannon Index ◽  
Index Formula ◽  
Bacterial Populations ◽  
Energetic Charge

During the spring, an experiment was conducted on the production of natural phytoplankton in a continuous flow layout of large capacity, and an analysis was made of the simultaneous evolution of microplanktonic populations (taxonomic composition, diversity, class ranges, and energetic charge) and of bacterial populations (structure, diversity, dominances, and catabolic potentialities).Oligotrophic initial conditions were characterized by a poor (0.22 μg of chlorophyll a/L) and diversified (pigment diversity = 4.5) phytoplankton with nanoplanktonic dominance associated with several benthic type diatoms. Bacterial flora, in which pseudomonads were dominant (54.5%), were also diversified (Shannon index [Formula: see text]). Metabolic potentialities of these bacterial communities were several. Enrichment of the milieu caused the selection and development of a small number of algal species dominated by the diatoms Skeletonema costatum (64 × 106/L)and Chaetoceros (3.2 × 106/L) leading to a paucispecific population with a large biomass, a pigment diversity of 1.97, and a chlorophyll a concentration of 25.08 μg/L. The bacterial community then became diversified [Formula: see text] and, although pseudomonads remained dominant (62%), a larger use of organic micromolecules was noted.The establishment of this phytoplanktonic community was followed by a zooplanktonic development in which larger species succeeded smaller ones (ciliates, tintinnides, rotifers, and copepods) corresponding to the global increase of the phytobiomass. Although this system appeared to be in a phase of relative stability, a decrease in the energetic charge showed a disturbance in the physiological state of the planktonic populations. These phenomena led to the vanishing of the diatom's dominance (Chaetoceros, and then S. costatum) and its replacement by nanoplankton (123 × 106 cells/L) and dinoflagellates (300 00 cells/L). A modification in the organic wealth of the milieu with the addition of a particular complex material that was not or little degraded caused deep disturbances in the bacterial populations. Their diversity reached a very low level ([Formula: see text] to 2.25) with a proliferation of vibrions (up to 74%) well equipped with exoenzymes, but more restricted in their nutritional versatility (marked preference for organic macromolecules).During the final phase of experimentation, despite a change in qualitative composition and a more important biomass, microplanktonic and bacterial populations returned to a diversified state nearing that of the initial conditions (pigment diversity = 3.2; [Formula: see text]). [Journal translation]

scholarly journals Morphological and Physiological Characteristics of Leea coccinia and Leea rubra in Response to Light Flux

HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 400-403 ◽  
Author(s):  
J.M. Sarracino ◽  
R. Merrit ◽  
C.K. Chin
Keyword(s):  
Chlorophyll A ◽  
Light Flux ◽  
Dry Weight ◽  
Anthocyanin Content ◽  
Total Chlorophyll ◽  
Low Light ◽  
Lighting Conditions ◽  
Interior Lighting ◽  
Chlorophyll A And B ◽  
Foliage Plant

Two foliage plant species, Leea coccinia L. and Leea rubra L., were evaluated for survival and for morphological and physiological changes in response to low light flux. Both species of Leea survived in light as low as that survived by Ficus benjamina L. Following 124 days under simulated interior lighting conditions of 5.7, 2.6, or 0.70 mol·m-2·day-1, L. coccinia, L. rubra, and F. benjamina plants grown in 92% shade had lower total fresh/dry weight, smaller leaf area, and thinner leaves than plants grown in full sun. After 124 days, plants of all three species in 92% shade were shorter, narrower, and had fewer growing points than plants in full sun. After 124 days, plants of L. coccinia grown in 92% shade contained more total chlorophyll, and more chlorophyll a and b, and they had a lower chlorophyll a: b ratio than plants from full sun. Anthocyanin content in L. rubra plants grown in 92% shade was lower than that of plants grown in full sun. Plants of F. benjamina grown in 92% shade contained more total chlorophyll and more chlorophyll a and b than plants grown in full sun.

scholarly journals SEASONAL ASSESSMENT OF HYDROGRAPHIC VARIABLES AND PHYTOPLANKTON COMMUNITY IN THE ARABIAN SEA WATERS OF KERALA, SOUTHWEST COAST OF INDIA

2014 ◽  
Vol 62 (4) ◽  
pp. 279-289 ◽  
Author(s):  
Sushanth Vishwanath Rai ◽  
Madaiah Rajashekhar
Keyword(s):  
Dissolved Oxygen ◽  
Chlorophyll A ◽  
Arabian Sea ◽  
Monsoon Season ◽  
Skeletonema Costatum ◽  
Principal Component ◽  
Significant Negative Correlation ◽  
Post Monsoon ◽  
Chaetoceros Curvisetus ◽  
Axis I

The seasonal variation of the hydrographic variables and phytoplankton species in the Arabian Sea waters of the Kerala coast, Southern India was investigated during different seasons. The variables such as pH, temperature, salinity, turbidity and chlorophyll-a contents of water were found to be high during pre-monsoon season and the dissolved oxygen content was minimal. The concentration of nutrients viz., nitrate, phosphate, silicate varied independently. In the study a total of 53 species of phytoplankton were recorded. Their density was higher during the post-monsoon season than during other seasons and the diatoms were found to be the dominant species. The major phytoplankton in terms of frequency and abundance were the species namely, Biddulphia mobiliensis, Chaetoceros curvisetus, Licmophora abbreviata, Skeletonema costatum, Prorocentrum micans and Oscillatoria sp. They showed significant positive correlation with pH, temperature, salinity, nitrate, phosphate and chlorophyll-a contents, whereas turbidity, dissolved oxygen and silicate exhibited significant negative correlation. The Principal Component Analysis (PCA) developed two principal components with 84.74% of total variability in the water quality which separated pre- and post-monsoon periods from the monsoon season on axis I, and pre-monsoon and monsoon periods from post-monsoon on axis II.

scholarly journals Heavy Elements Produced in Supernova Explosion and thier Propulsion in the ISM

2013 ◽  
Vol 9 (S296) ◽  
pp. 390-391
Author(s):  
Rulee Baruah
Keyword(s):  
Experimental Data ◽  
Supernova Explosion ◽  
Neutron Number ◽  
Light Curves ◽  
Heavy Elements ◽  
Low Density ◽  
Number Density ◽  
R Process

AbstractWe study the r-process path at temperatures from 1.0–3.0 × 109K and neutron number density from 1020-1030cm−3. At low density of 1020 cm−3 and T9 = 2.0, the path contains all the elements as given by experimental data of Wapstra et al. (2003). The element 98Cf254 shown by supernova light curves is found in our results. We take iron (Z = 26) as seed for calculation of abundances for supernova.

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