Oxygen Inhibition of Photosynthetic Oxygen Evolution in Marine Plants

1976 ◽  
Vol 3 (1) ◽  
pp. 73 ◽  
Author(s):  
WJS Downton ◽  
DG Bishop ◽  
AWD Larkum ◽  
CB Osmond
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Sea Water ◽  
Oxygen Electrode ◽  
Photosynthetic Oxygen Evolution ◽  
Pocillopora Damicornis ◽  
Oxygen Inhibition ◽  
Rate Of Photosynthesis ◽  
Tridacna Maxima ◽  
Effect Of Oxygen

The effect of oxygen concentration on oxygen exchange in six species of the Chlorophyta, one of the Cyanophyta, one of the Rhodophyta, three of the Phaeophyta, zooxanthellae from Tridacna maxima (clam) and Pocillopora damicornis (coral), and a marine angiosperm was investigated with a polaro- graphic oxygen electrode. The rate of photosynthesis in air-saturated sea water ranged from 14 to 248 micromoles of oxygen evolved per hour per milligram of chlorophyll. Photosynthesis was inhibited by 15-85% in sea water adjusted to between 65 and 90% of oxygen saturation. A post- illumination burst of oxygen uptake was observed on darkening and the size of this burst was in- fluenced by oxygen concentration. Steady-state rates of oxygen uptake in the dark were enhanced at higher oxygen tensions. The likelihood that the dissolved oxygen content of sea water may regulate the productivity of reef communities is discussed.

scholarly journals The Oxygen Uptake of the Lobster (Homarus Vulgaris Edw.)

1954 ◽  
Vol 31 (2) ◽  
pp. 228-251
Author(s):  
H. J. THOMAS
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Sea Water ◽  
Carbon Dioxide Concentration ◽  
Ventilation Rate ◽  
Gill Ventilation ◽  
Increasing Temperature ◽  
The Relationship ◽  
Respiratory Movements

1. In sea water the oxygen uptake of Homarus vulgaris is directly proportional to the oxygen concentration. The relationship applies over the temperature range 6-18°C. 2. Within specified limits of size and condition, oxygen uptake is the same for both sexes. 3. The relative oxygen uptake in sea water decreases as the weight of the animal increases. 4. Oxygen uptake in sea water is effected mainly through the gills. The abdominal swimmerets, however, also serve in respiration and account for approximately 3 % of the total oxygen uptake. 5. In sea water of constant oxygen tension, oxygen uptake increases with increasing temperature. 6. Increase in oxygen uptake with temperature in sea water is mainly brought about by an increase in the gill ventilation rate. In addition, the degree of utilization increases. The relationship is a direct reflexion of the increased metabolic activity. 7. The ventilation rate of gills is unaffected by a decrease of oxygen. 8. The percentage of oxygen extracted by the gills increases as the oxygen concentration of the medium decreases. 9. Under the influence of carbon dioxide respiratory movements become retarded at acidities greater than about pH 7.0 and are completely inhibited at around pH 6.5. At acidities less than pH 7.0 changes in the carbon dioxide concentration are without effect on the rate of the respiratory movements. 10. The oxygen uptake in air, notwithstanding its low level, is directly proportional to temperature. 11. The significance of the above results in relation to the respiratory functions of the blood is discussed.

Effect of Oxygen Concentration and pH on Electrode Potential of Stainless Steels and Operation of Microcouples

CORROSION ◽  
1966 ◽  
Vol 22 (1) ◽  
pp. 16-20 ◽  
Author(s):  
YU. M. KOROVIN ◽  
I B. ULANOVSKII
Keyword(s):  
Oxygen Concentration ◽  
Stainless Steels ◽  
Electrode Potential ◽  
Sea Water ◽  
Relative Effect ◽  
Solution Ph ◽  
Corrosion Rates ◽  
Electrode Potentials ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

Abstract Using Russian steels of 13 Cr and 18–9 analyses in general experiments are conducted varying pH and oxygen concentrations in sea water to determine the relative effect of these variables on corrosion rates in crevices. Effect of oxygen concentrations in the range 1–9 mg/1 and pH 8.3 to 2.3 are reported. Changes in pH were found to strongly and changes in oxygen concentration weakly influence the corrosion rate. Authors postulate that anodic passivity is effected after application of tenths of a milliampere per square centimeter whereas when the pH in the anodic space is lowered, critical current density required for passivation increases 40–50 fold. Heat treatment of the steel does not influence electrode potentials when solution pH is lowered.

Respiratory metabolism of Azotobacter vinelandii cells at oxygen concentrations that initially range from suboptimal to supraoptimal for nitrogenase activity

1991 ◽  
Vol 37 (4) ◽  
pp. 321-325 ◽  
Author(s):  
Jay B. Peterson
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Apparent Affinity ◽  
Lower Oxygen ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

The effects of three low oxygen concentrations on nitrogenase activity, total oxygen uptake, and respiratory parameters (Vmax and Ks(O2) of N2-grown Azotobacter vinelandii were studied in acetylene reduction assays during a 2-h incubation. The cell suspensions were taken from cultures grown at low aeration. Total oxygen uptake was higher with each increment in oxygen concentration. The highest oxygen concentration was initially supraoptimal for nitrogenase activity. The Ks(O2) values, representing the apparent affinity of the respiration system for oxygen, increased during the incubation of cells at the highest oxygen concentration. The Ks(O2) values at the two lower oxygen concentrations decreased and were very similar. A small effect of oxygen on the Vmax was observed. These results show that the metabolism determining the apparent affinity of the system for oxygen responds to the oxygen concentrations. Furthermore, this metabolism did not substantially increase the Ks(O2) unless the oxygen concentration was high enough to inhibit nitrogenase activity, indicating that the two processes may be linked. Key words: Azotobacter, oxygen regulation, nitrogen fixation.

Inhibition of photosynthesis by low oxygen concentrations

1981 ◽  
Vol 59 (5) ◽  
pp. 721-725 ◽  
Author(s):  
P. B. E. McVetty ◽  
D. T. Canvin
Keyword(s):  
Oxygen Concentration ◽  
High Light ◽  
Low Oxygen ◽  
Low Light ◽  
Light Intensities ◽  
Oxidation Reduction ◽  
Transport Chain ◽  
Rate Of Photosynthesis ◽  
Effect Of Oxygen ◽  
Temporary Inhibition

The effect of changing the oxygen concentration from 21 to 2% on photosynthesis of wheat, sunflower, and soybean was investigated. At low CO2 concentrations and low light intensities, a stimulation of photosynthesis was observed in 2% oxygen compared with the rate in 21% O2. At high CO2 concentrations and high light intensities, a temporary inhibition of photosynthesis was observed when the oxygen concentration was changed from 21 to 2%. In wheat and sunflower, this inhibition was observed at progressively lower CO2 concentrations as temperatures were decreased. In soybean only, a slight inhibition of photosynthesis was observed at higher temperatures. In some cases, especially in plants grown under a low light intensity, a long-lasting (> 45 min) inhibition of photosynthesis was observed. In most cases, however, the inhibition lasted only for several minutes and final rates of photosynthesis in 2% O2 were equal to or greater than the rate of photosynthesis in 21% O2. The stimulatory effect of oxygen on photosynthesis at high CO2 concentrations and high light intensities could possibly be due to a regulation of the oxidation–reduction state of the electron transport chain and the maintenance of phosphorylation.

scholarly journals Effect of Oxygen Concentration on the Detection of Mercury in an Atmospheric Microwave Discharge

1999 ◽  
Vol 38 (Part 1, No. 7B) ◽  
pp. 4595-4600 ◽  
Author(s):  
Kamal Hadidi ◽  
Paul P. Woskov ◽  
Guadalupe J. Flores ◽  
Kareen Green ◽  
Paul Thomas
Keyword(s):  
Oxygen Concentration ◽  
Microwave Discharge ◽  
Effect Of Oxygen

Effect of oxygen concentration and temperature on ignition time of polypropylene

2012 ◽  
Vol 110 (1) ◽  
pp. 485-487 ◽  
Author(s):  
Jozef Martinka ◽  
Karol Balog ◽  
Tomáš Chrebet ◽  
Emília Hroncová ◽  
Janka Dibdiaková
Keyword(s):  
Oxygen Concentration ◽  
Ignition Time ◽  
Effect Of Oxygen
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