State-transitions facilitate robust quantum yields and cause an over-estimation of electron transport in Dunaliella tertiolecta cells held at the CO2 compensation point and re-supplied with DIC

2013 ◽  
Vol 119 (3) ◽  
pp. 257-272 ◽  
Author(s):  
Sven Ihnken ◽  
Jacco C. Kromkamp ◽  
John Beardall ◽  
Greg M. Silsbe
Keyword(s):  
Electron Transport ◽  
Dunaliella Tertiolecta ◽  
Compensation Point ◽  
Quantum Yields ◽  
State Transitions ◽  
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.

scholarly journals Photomorphogenesis in the Picocyanobacterium Cyanobium gracile Includes Increased Phycobilisome Abundance Under Blue Light, Phycobilisome Decoupling Under Near Far-Red Light, and Wavelength-Specific Photoprotective Strategies

2021 ◽  
Vol 12 ◽  
Author(s):  
Gábor Bernát ◽  
Tomáš Zavřel ◽  
Eva Kotabová ◽  
László Kovács ◽  
Gábor Steinbach ◽  
...  
Keyword(s):  
Electron Transport ◽  
Growth Rates ◽  
Incident Light ◽  
Red Light ◽  
Photosynthetic Performance ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Strong Light ◽  
Antenna Size ◽  
Moderate Growth

Photomorphogenesis is a process by which photosynthetic organisms perceive external light parameters, including light quality (color), and adjust cellular metabolism, growth rates and other parameters, in order to survive in a changing light environment. In this study we comprehensively explored the light color acclimation of Cyanobium gracile, a common cyanobacterium in turbid freshwater shallow lakes, using nine different monochromatic growth lights covering the whole visible spectrum from 435 to 687 nm. According to incident light wavelength, C. gracile cells performed great plasticity in terms of pigment composition, antenna size, and photosystem stoichiometry, to optimize their photosynthetic performance and to redox poise their intersystem electron transport chain. In spite of such compensatory strategies, C. gracile, like other cyanobacteria, uses blue and near far-red light less efficiently than orange or red light, which involves moderate growth rates, reduced cell volumes and lower electron transport rates. Unfavorable light conditions, where neither chlorophyll nor phycobilisomes absorb light sufficiently, are compensated by an enhanced antenna size. Increasing the wavelength of the growth light is accompanied by increasing photosystem II to photosystem I ratios, which involve better light utilization in the red spectral region. This is surprisingly accompanied by a partial excitonic antenna decoupling, which was the highest in the cells grown under 687 nm light. So far, a similar phenomenon is known to be induced only by strong light; here we demonstrate that under certain physiological conditions such decoupling is also possible to be induced by weak light. This suggests that suboptimal photosynthetic performance of the near far-red light grown C. gracile cells is due to a solid redox- and/or signal-imbalance, which leads to the activation of this short-term light acclimation process. Using a variety of photo-biophysical methods, we also demonstrate that under blue wavelengths, excessive light is quenched through orange carotenoid protein mediated non-photochemical quenching, whereas under orange/red wavelengths state transitions are involved in photoprotection.

Quantum Yields of Photosystem II Electron Transport and Carbon Dioxide Fixation in C4 Plants

1990 ◽  
Vol 17 (5) ◽  
pp. 579 ◽  
Author(s):  
JP Krall ◽  
GE Edwards
Keyword(s):  
Carbon Dioxide ◽  
Electron Transport ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Malic Enzyme ◽  
Co2 Fixation ◽  
C4 Plants ◽  
Quantum Yields ◽  
Ps Ii ◽  
Co2 Concentrations

The quantum yields of non-cyclic electron transport from photosystem II (determined from chlorophyll a fluorescence) and carbon dioxide assimilation were measured in vivo in representative species of the three subgroups of C4 plants (NADP-malic enzyme, NAD-malic enzyme and PEP-carboxykinase) over a series of intercellular CO2 concentrations (CI) at both 21% and 2% O2. The CO2 assimilation rate was independent of O2 concentration over the entire range of Ci (up to 500 μbar) in all three C4 subgroups. The quantum yield of PS II electron transport was similar, or only slightly greater, in 21% v. 2% O2 at all Ci values. In contrast, in the C3 species wheat there was a large O2 dependent increase in PS II quantum yield at low CO2, which reflects a high level of photorespiration. In the C4 plants, the relationship of the quantum yield of PS II electron transport to the quantum yield of CO2 fixation is linear suggesting that photochemical use of energy absorbed by PS II is tightly linked to CO2 fixation in C4 plants. This relationship is nearly identical in all three subgroups and may allow estimates of photosynthetic rates of C4 plants based on measurements of PS II photochemical efficiency. The results suggest that in C4 plants both the photoreduction of O2 and photorespiration are low, even at very limiting CO2 concentrations.

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.

Oxygen-sensitive Differences in the Relationship between Photosynthetic Electron Transport and CO2 Assimilation in C3 and C4 Plants during State Transitions

1997 ◽  
Vol 24 (4) ◽  
pp. 495 ◽  
Author(s):  
James R. Andrews ◽  
Neil R. Baker
Keyword(s):  
Electron Transport ◽  
Quantum Efficiency ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
State Transitions ◽  
Large Decrease ◽  
Maize Leaves ◽  
Significant Change ◽  
The Relationship ◽  
State 1

Wheat (C3) and maize (C4) leaves were exposed to light treatments that were limiting for CO2 assimilation and which excite preferentially photosystem I (PSI) or photosystem II (PSII) and induce State 1 or State 2, respectively. In order to examine the relationships between linear electron transport and CO2 in leaves during State transitions, simultaneous measurements of CO2 assimilation, chlorophyll fluorescence and absorbance at 820 nm were used to estimate the quantum efficiencies of CO2 assimilation and PSII and PSI photochemistry. In wheat leaves with photorespiratory activity, no significant change in quantum efficiency of CO2assimilation was observed during State transitions. This was not the case when photorespiration was inhibited with either 2% O2 or 1000 ppm CO2 and transition from State 2 to State 1 was accompanied by a large decrease (c. 20%) in the quantum efficiency of CO2 assimilation which was not associated with a decrease in the quantum efficiency of electron transport through PSII. Photorespiration appears to buffer the quantum efficiency of CO2 assimilation from changes associated with decreases in the rate of CO2 fixation resulting from imbalances in PPFD absorption by PSI and PSII. When maize leaves were subjected to similar State transitions, no significant change in the quantum efficiency of CO2 assimilation was observed on transition from State 2 to State 1, but on switching back to State 2 a very large decrease (c. 40%) was observed. This decrease could be prevented if leaves were maintained in either 2% O2 or 593 ppm CO2. The possible occurrence of photorespiration in maize leaves on transition from State 1 to State 2, which could result from an inhibition of the CO2 concentrating mechanism, cannot account for the decrease in the quantum efficiency of CO2 assimilation since the relationship between PSII electron transport and CO2 assimilation remained similar throughout the State transitions. Also changes in the phosphorylation status of the light-harvesting chlorophyll a/b protein associated with PSII cannot be implicated in this phenomenon.

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
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