scholarly journals An Assessment of Photosynthetic Activity in Large Benthic Foraminifers and the Optimization of Light Intensity for Lab-scale Cultivation

2021 ◽  
Vol 19 (3) ◽  
pp. 120-129
Author(s):  
Shumona Akther ◽  
Wenzhao Sun ◽  
Preeti Pokhrel ◽  
Jumpei Suzuki ◽  
Masafumi Fujita
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Benthic Foraminifers

scholarly journals Effects of Photosynthetic Activity Radiation (PAR) on Green Mustard Plant Growth (Brassica rapa var. parachinensis L.)

2019 ◽  
Vol 20 (1) ◽  
pp. 19
Author(s):  
Ni Nyoman Ratini ◽  
I Wayan Supardi ◽  
Yuli Nurfadhillah
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Plant Height ◽  
Photosynthetic Activity ◽  
Plant Biomass ◽  
Vegetative Phase ◽  
Active Radiation ◽  
Blue Filter ◽  
Mustard Plant ◽  
Number Of Leaves

A research on the effect of photosynthetic active radiation (PAR) on the growth of green mustard plants has been conducted. The radiation source used is sunlight. Samples have been grouped as a sample which treated by red filter (P1), by orange filter (P2), by purple filter (P3), by green filter (P4), by blue filter (P5) and a sample without filter as a control (P0). Each sample consisted of four plants. The planting was carried out using polybags with compost media. Observations were made from the nursery phase to the slow vegetative phase (day 3rd, when all plants had grown shoots until day 63rd of the harvest). Parameters measured include light intensity, plant height and number of leaves. Measurement is done every three days. Also it measured plant biomass on the last day of observation (63rd day). The results showed that the intensity of each sample had an impact on the harvest. The best growth rate is obtained in P2, both in the nursery phase and fast vegetative phase i.e. 0.119 cm/day and 0.194 cm/day, respectively. While the highest growth rate was obtained in the P3 sample, namely the slow vegetative phase (0.035 cm/day). Overall the best planting results were obtained in P2 samples with plant height of 23.18 cm, number of leaves of 12 strands and plant biomass of 33.56 g.

Investigations on the photosynthetic sulfur bacterium Chlorobium phaeobacteroides causing seasonal blooms in Lake Kinneret

1979 ◽  
Vol 25 (9) ◽  
pp. 999-1007 ◽  
Author(s):  
T. Bergstein ◽  
Y. Henis ◽  
B. Z. Cavari
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Large Population ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Organic Substrate ◽  
Lake Kinneret ◽  
Sulfur Bacteria ◽  
Chlorobium Phaeobacteroides ◽  
Photosynthetic Sulfur Bacteria

Between May and December, the annual stratification period in Lake Kinneret, sulfide is formed and accumulates in the hypolimnion. In July–August a large population (up to 106 cells/mL) of green, photosynthetic, sulfur bacteria develops at the boundary of the oxidative and reductive zones of the water column lasting for 3–8 weeks. These bacteria were isolated from the lake and identified as Chlorobium phaeobacteroides. Optimal growth conditions included 160 mg S=L−1 and light intensities of 5–0 μEinstein (μE) m−2s−1. Glucose and acetate augmented growth when added to the mineral medium. The lowest light intensity which still supported growth was 0.3 μE m−2s−1 when acetate was present and 1.0 μE m−2s−1 when no organic substrate was present. Under complete darkness, either with or without organic substrate, the bacteria die. Photosynthetic activity was higher when no organic compound was added to the medium. Uptake of acetate was light-dependant.In the lake the photosynthetic activity of the bacteria is low because of the limited light intensity (0.3 μE m−2s−1) at the bloom layer. It is suggested that the appearance and the disappearance of the bloom are caused by the influence of the daily internal seiche.

scholarly journals Photosynthesis in Relation to Leaf Orientation and Light Interoeption

1964 ◽  
Vol 17 (3) ◽  
pp. 591 ◽  
Author(s):  
PE Kriedeman ◽  
TF Neales ◽  
DH Ashton
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Geometrical Optics ◽  
Angle Of Incidence ◽  
Similar Relationship ◽  
Photosynthetic Response ◽  
Leaf Orientation ◽  
Incoming Radiation

This paper examines the photosynthetic response of single attached leaves (of four different species) to an increasing angle of incidence (8) of incoming radiation. The intensity of light falling upon a leaf can be deduced from geometrical optics to be proportional to cos 8. The results reported here suggest that the photosynthetic. activity of leaves exposed to a limiting light intensity follows a similar relationship. Explanations of this empirically determined relationship are discussed.

Measurement of microalgal photosynthetic activity depending on light intensity and quality

2005 ◽  
Vol 27 (2) ◽  
pp. 127-131 ◽  
Author(s):  
You-Chul Jeon ◽  
Chul-Woong Cho ◽  
Yeoung-Sang Yun
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity

scholarly journals Analysis of the light intensity dependence of the growth ofSynechocystisand of the light distribution in a photobioreactor energized by 635 nm light

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5256 ◽  
Author(s):  
Alessandro Cordara ◽  
Angela Re ◽  
Cristina Pagliano ◽  
Pascal Van Alphen ◽  
Raffaele Pirone ◽  
...  
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Genetic Manipulation ◽  
Incident Light ◽  
Red Light ◽  
Clear Correlation ◽  
Heterogeneous Distribution ◽  
Cultivation System ◽  
Modelling Studies ◽  
Set Up

Synechocystisgathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation.Synechocystisphysiology and metabolism, and consequently, the productivity ofSynechocystis-based photobioreactors (PBRs), are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange–red light intensities onSynechocystisgrowth characteristics and photosynthetic activity.Synechocystisgrowth and photosynthetic activity were found to raise as supplied light intensity increased up to 500 μmol photons m−2s−1and to enter the photoinhibition state only at 800 μmol photons m−2s−1. Interestingly, reverting the light to a non-photo-inhibiting intensity unveiledSynechocystisto be able to promptly recover. Furthermore, our characterization displayed a clear correlation between variations in growth rate and cell size, extending a phenomenon previously observed in other cyanobacteria. Further, we applied a modelling approach to simulate the effects produced by varying the incident light intensity on its local distribution within the PBR vessel. Our model simulations suggested that the photosynthetic activity ofSynechocystiscould be enhanced by finely regulating the intensity of the light incident on the PBR in order to prevent cells from experiencing light-induced stress and induce their exploitation of areas of different local light intensity formed in the vessel. In the latter case, the heterogeneous distribution of the local light intensity would allowSynechocystisfor an optimized usage of light.

scholarly journals Photosystem II core quenching in desiccated Leptolyngbya ohadii

2019 ◽  
Vol 143 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Reza Ranjbar Choubeh ◽  
Leeat Bar-Eyal ◽  
Yossi Paltiel ◽  
Nir Keren ◽  
Paul C. Struik ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Light Intensity ◽  
Photosynthetic Activity ◽  
High Light Intensity ◽  
Primary Electron ◽  
High Light ◽  
Harsh Environment ◽  
Primary Electron Donor ◽  
Protection Mechanism ◽  
The Core

Abstract Cyanobacteria living in the harsh environment of the desert have to protect themselves against high light intensity and prevent photodamage. These cyanobacteria are in a desiccated state during the largest part of the day when both temperature and light intensity are high. In the desiccated state, their photosynthetic activity is stopped, whereas upon rehydration the ability to perform photosynthesis is regained. Earlier reports indicate that light-induced excitations in Leptolyngbya ohadii are heavily quenched in the desiccated state, because of a loss of structural order of the light-harvesting phycobilisome structures (Bar Eyal et al. in Proc Natl Acad Sci 114:9481, 2017) and via the stably oxidized primary electron donor in photosystem I, namely P700+ (Bar Eyal et al. in Biochim Biophys Acta Bioenergy 1847:1267–1273, 2015). In this study, we use picosecond fluorescence experiments to demonstrate that a third protection mechanism exists, in which the core of photosystem II is quenched independently.

Transformation of plastids in the leaves of Acer negundo L. var. odessanum (H. Rothe)

1975 ◽  
Vol 18 (3) ◽  
pp. 509-518
Author(s):  
M. Wrischer ◽  
N. Ljubesic ◽  
Z. Divide
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
Pigment Concentration ◽  
Low Light ◽  
Acer Negundo ◽  
Green Leaves ◽  
Low Light Intensity ◽  
Dark Green

The leaves of Acer negundo L. var. odessanum (H. Rothe), if permanently exposed to strong sunlight, do not green, but remain yellow and finally become bleached. In yellow leaves the plastids contain single thylakoids and no grana. In plastids of bleached leaves, however, only vesicles are present. The concentration of chlorophylls and photosynthetic activity are much lower in those leaves than in the green ones. If the illumination is reduced (e.g. by shading) both the yellow and the bleached leaves become greenish, and even fully green after a few days at a sufficiently low light intensity. The plastids of yellow-green leaves contain small grana. In dark green leaves the thylakoid system of the chloroplasts is normally developed forming true grana, regardless of whether the leaves were originally green, or became green by shading the yellow or bleached ones. Their pigment concentration and photosynthetic activity are also normal. If green leaves are exposed to sunlight they do not yellow or bleach. During a 3-week period the structure of the thylakoid system did not perceivably change, with the exception that large plastoglobules formed in the stroma.

Response of chlorina barley mutants to heat stress under low and high light

2003 ◽  
Vol 30 (5) ◽  
pp. 515 ◽  
Author(s):  
Katya Georgieva ◽  
Ivanka Fedina ◽  
Liliana Maslenkova ◽  
Violeta Peeva
Keyword(s):  
Heat Stress ◽  
Light Intensity ◽  
Photosynthetic Activity ◽  
High Light Intensity ◽  
High Light ◽  
O2 Evolution ◽  
Wild Type ◽  
Hordeum Vulgare L ◽  
Low Light ◽  
Low Light Intensity

Barley plants (Hordeum vulgare L.) of wild type and two chlorina mutants, chlorina 126 and chlorina f2, were subjected to 42°C for 5 h at light intensities of 100 and 1000 μmol photons m–2 s–1. The exposure of plants to heat stress at a light intensity of 100 μmol m–2 s–1 induced enormous proline accumulation, indicating that the effect of heat stress was stronger when it was combined with low light intensity. The functional activity of PSII, O2�evolution and flash-induced thermoluminescence B-band amplitude were strongly reduced when plants were exposed to heat at low light intensity. The results clearly showed that high light intensity had a protective effect on photosynthetic activity when barley plants were treated with high temperature. Comparison of the thermosensitivity of wild type plants and chlorina mutants revealed that O2 evolution in chlorina 126 and, especially, in chlorina f2 was more sensitive to heat than in wild type.

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