scholarly journals The Effect of pH, O2, and Temperature on the CO2 Compensation Point of Isolated Asparagus Mesophyll Cells

1987 ◽  
Vol 83 (1) ◽  
pp. 113-117 ◽  
Author(s):  
George S. Espie ◽  
Brian Colman
Keyword(s):  
Compensation Point ◽  
Mesophyll Cells ◽  
Effect Of Ph ◽  
Co2 Compensation Point

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

C4 Photosynthesis in Sodium-Deficient Plants

1979 ◽  
Vol 6 (4) ◽  
pp. 431 ◽  
Author(s):  
TS Boag ◽  
PF Brownell
Keyword(s):  
C4 Photosynthesis ◽  
Dicarboxylic Acids ◽  
C4 Plants ◽  
Compensation Point ◽  
Short Term ◽  
Sodium Deficiency ◽  
Co2 Compensation Point ◽  
Δ13c Value ◽  
C4 Pathway ◽  
Chloris Barbata

The C4 plants Kochia childsii Hort. and Chloris barbata Sw. showed symptoms characteristic of sodium deficiency. The δ13C value, CO2 compensation point and percentage of 14C label in C4 dicarboxylic acids in short-term photosynthesis were similar in sodium-deficient and normal plants. This is consistent with the operation of the C4 pathway.

Leaf anatomy, gas exchange and photosynthetic enzyme activity in Flaveria kochiana

2007 ◽  
Vol 34 (2) ◽  
pp. 118 ◽  
Author(s):  
Erika A. Sudderth ◽  
Riyadh M. Muhaidat ◽  
Athena D. McKown ◽  
Ferit Kocacinar ◽  
Rowan F. Sage
Keyword(s):  
Gas Exchange ◽  
Leaf Anatomy ◽  
Carbon Isotope Ratio ◽  
Compensation Point ◽  
Initial Slope ◽  
Kranz Anatomy ◽  
Pyruvate Orthophosphate Dikinase ◽  
Co2 Compensation Point ◽  
C4 Species ◽  
Flaveria Species

Flaveria (Asteraceae) is one of the few genera known to contain both C3 and C4 species, in addition to numerous biochemically-intermediate species. C3-C4 and C4-like intermediate photosynthesis have arisen more than once in different phylogenetic clades of Flaveria. Here, we characterise for the first time the photosynthetic pathway of the recently described species Flaveria kochiana B.L. Turner. We examined leaf anatomy, activity and localisation of key photosynthetic enzymes, and gas exchange characteristics and compared these trait values with those from related C4 and C4-like Flaveria species. F. kochiana has Kranz anatomy that is typical of other C4 Flaveria species. As in the other C4 lineages within the Flaveria genus, the primary decarboxylating enzyme is NADP-malic enzyme. Immunolocalisation of the major C4 cycle enzymes, PEP carboxylase and pyruvate, orthophosphate dikinase, were restricted to the mesophyll, while Rubisco was largely localised to the bundle sheath. Gas exchange analysis demonstrated that F. kochiana operates a fully functional C4 pathway with little sensitivity to ambient oxygen levels. The CO2 compensation point (2.2 µbar) was typical for C4 species, and the O2-response of the CO2 compensation point was the same as the C4 species F. trinervia. Notably, F. vaginata (B.L. Robinson & Greenman), a putative C4-like species that is the nearest relative of F. kochiana, had an identical response of the CO2 compensation point to O2. Furthermore, F. vaginata, exhibited a carbon isotope ratio (–15.4‰) similar to C4 species including F. australasica Hooker, F. trinervia Spreng. C. Mohr and the newly characterised F. kochiana. F. vaginata could be considered a C4 species, but additional studies are necessary to confirm this hypothesis. In addition, our results show that F. kochiana uses an efficient C4 cycle, with the highest initial slope of the A/Ci curve of any C4 Flaveria species.

scholarly journals Uncertainty in measurements of the photorespiratory CO2 compensation point and its impact on models of leaf photosynthesis

2017 ◽  
Vol 132 (3) ◽  
pp. 245-255 ◽  
Author(s):  
Berkley J. Walker ◽  
Douglas J. Orr ◽  
Elizabete Carmo-Silva ◽  
Martin A. J. Parry ◽  
Carl J. Bernacchi ◽  
...  
Keyword(s):  
Compensation Point ◽  
Leaf Photosynthesis ◽  
Co2 Compensation Point

scholarly journals Estimating the interconversion between CO2 and organic matter in the environment using mathematical models and some considerations

2020 ◽  
Vol 17 (1) ◽  
pp. 56-67
Author(s):  
Tomás Aquino Portes
Keyword(s):  
Organic Chemistry ◽  
Organic Matter ◽  
Mathematical Models ◽  
Chemical Reactions ◽  
Co2 Concentration ◽  
Compensation Point ◽  
Photosynthetic Organisms ◽  
Co2 Compensation Point ◽  
The Earth ◽  
Organic Products

The aims was to use mathematical models to analyze the interconversion between the amount of organic matter produced and the consequent variation in the concentration of CO2 in the atmosphere and to discuss, supported by the data presented and the literature, possible changes in the Earth's environment. Scientific findings and evidence indicate that the concentrations of CO2 and O2 varied throughout the existence of the Earth. These variations were a consequence of the existing environment in different Eras, resulting in changes in all other processes that depended on these gases. Chemical reactions occurred and organic products such as petroleum arose abiotically. These products gave origin to organic chemistry and drastically reduced the concentration of CO2 and elevated O2 in the atmosphere. In the current plants, for each O2 produced in the photochemical step of photosynthesis, one CO2 is assimilated in the biochemical step. Supported by this relationship and by the results presented in this work, it can be inferred that the first photosynthetic organisms originated on Earth when the concentration of CO2 was possibly at a concentration below 1000 ppm. Biochemistry started with these organisms. The results suggest that the reduction in CO2 concentration was linear in relation to the age of the Earth, before the origin of photosynthetic organisms. This relationship changed with origin of these organisms, due to the major changes that occurred in the environment. There is evidence that in certain periods, CO2 concentrations have been reduced below the CO2 compensation point for certain plants resulting in the extinction of these plants and the organisms that depended on them.

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