Assimilatory power as a driving force in photosynthesis

Heber, U.; Neimanis, Spidola; Dietz, Karl‐Josef; Viil, Juta

doi:10.1016/0005-2728(86)90067-8

Cited by 76 publications

(56 citation statements)

References 32 publications

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“…Because a is considered a function of both light-harvesting efficiency and photosynthetic energy conversion efficiency (Henley 1993), the increasing value of a indicated that light-harvesting efficiency and/or photosynthetic energy conversion efficiency in C. raciborskii increased with at higher levels of CO 2 , which resulted from an enhancement in RUBISCO activity or a shift to greater light-harvesting efficiency. Previous studies suggest that Pi may be important in the cooperation of the photosynthetic machinery (Heber et al 1986), ATP production (Furbank et al 1986), indirect regulation of electron transport flow (Slovachek & Hind 1981) or the distribution of excitation energy between the two photosystems (Horton 1987). In this present study, increases in Pi also lead to increases in P m and a (Fig.…”

Section: Discussionsupporting

confidence: 75%

Combined effects of carbon and phosphorus levels on the invasive cyanobacterium, Cylindrospermopsis raciborskii

Zeng

et al. 2012

Phycologia

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The invasive cyanobacterium, Cylindrospermopsis raciborskii, was cultured semicontinuously for 18 days at different carbon and phosphorus levels. Growth and photosynthesis were measured to study the combined effects of CO 2 and phosphorus availabilities. The results showed that enrichment of CO 2 or inorganic phosphorus (Pi) levels in the culture medium significantly increased specific growth rate (m), light-saturated photosynthesis (P m ) and photosynthetic efficiency (a), but tended to decrease dark respiratory rate (R d ), saturating irradiance for photosynthesis (E k ) and the light compensation point (E c ). However, photosynthetic responses to inorganic carbon concentration in C. raciborskii were affected by interactions between CO 2 and Pi. At high Pi concentration, elevated CO 2 significantly increased the inorganic carbon-saturated photosynthesis rate (V max ) and substrate concentration giving half-maximal photosynthetic rate [K 0.5 (DIC)], whereas at low Pi levels, elevated CO 2 slightly decreased the values of V max and K 0.5 (DIC). Additionally, enrichment with Pi significantly increased K 0.5 (DIC) and V max regardless of the CO 2 level, suggesting that Pi plays a role in photosynthetic carbon fixation in C. raciborskii. Furthermore, when C. raciborskii was batch cultured in different carbon and phosphorus concentrations for 72 h, the uptake rate of nitrogen increased with enrichment of both CO 2 and Pi, while the uptake rate of phosphorus was enhanced only by increases in Pi concentration. The results suggest that the availability of CO 2 and phosphorus have combined and independent effects on photosynthesis and nutrient uptake in C. raciborskii, reflecting that changes in environmental factors could influence the dominance of this invasive cyanobacterium. These combined effects need to be considered when generalizing this species response to changing CO 2 levels.

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Section: Discussionsupporting

confidence: 75%

Combined effects of carbon and phosphorus levels on the invasive cyanobacterium, Cylindrospermopsis raciborskii

Zeng

et al. 2012

Phycologia

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“…3). TPT, the prime photosynthate exporter, rapidly equilibrates metabolite state of the glyceraldehde-3-phosphate reduction reaction between stroma and cytosol enabling instantaneous information exchange on the NAD(P)H and ATP system thus energization state, 19 and may activate mitogen activated protein kinase 6 (MPK6). Especially the highly responsive AP2/ ERF-TF network is regulated via this pathway.…”

Section: -11mentioning

confidence: 99%

The acclimation response to high light is initiated within seconds as indicated by upregulation of AP2/ERF transcription factor network inArabidopsis thaliana

Moore

Vogel

Dietz³

2014

Plant Signaling & Behavior

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“…Measurements in intact leaves, however, would suggest that the degree of control in vivo exerted by this limitation on plastoquinol oxidation is relatively constant with respect to irradiance in air (4, 14), although not in the absence of CO2 (11). In addition, it has been demonstrated that the acidification of the thylakoid lumen also has direct effects on the quantum efficiency of PSII (9, 30).Although both feed-forward and feedback mechanisms are well characterized in vitro (1,2,4,8,9,16,17), the relative extent of the influence of each in vivo is unclear (4,8 …”

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confidence: 99%

Control of the Quantum Efficiencies of Photosystems I and II, Electron Flow, and Enzyme Activation following Dark-to-Light Transitions in Pea Leaves

Foyer

Lelandais²,

Harbinson³

1992

Plant Physiol.

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The quantum efficiencies of photosystems I and 11 (PSI and PSII), [NADP]/[NADPH] ratios, and the activities of chloroplastic fructose-1,6-bisphosphatase and NADP-malate dehydrogenase were measured in intact pea (Pisum sativum L.) leaves in air following the transition from darkness to 750 microeinsteins per square meter per second irradiance. PSII efficiency declined from a low value to a minimum within the first 10 to 15 seconds of irradiance, after which it increased progressively to the steady-state value. The resistance of electron flow between the photosystems was high at this time, but it was not the principal factor limiting electron flow. Oxidation of P700 was restricted by acceptor side processes for approximately the first 60 seconds of illumination. Once the acceptor side limitation was relieved, the oxidation state of P700 was used to estimate the quantum efficiency of electron transport by PSI. This was observed to increase progressively with time. The quantum efficiencies of both photosystems increased in parallel, consistent with a predominant role for noncyclic electron transport. Fructose-1,6-bisphosphatase activity increased in an approximately sigmoidal fashion with time of irradiance, paralleling the changes in the quantum efficiencies of the photosystems. In contrast, the activation of NADP-malate dehydrogenase did not show a lag period but increased with time, reaching a maximum value at about 50 seconds of illumination, after which it declined. The NADP pool was not extensively reduced during the first 10 seconds of illumination, but became so subsequently. It remained in the reduced state until about 60 seconds of illumination and then became relatively oxidized. The empirical relationship between NADPmalate dehydrogenase activity and the reduction state of the NADP pool supports the suggestion that NADP-malate dehydrogenase activity is a useful estimate of the reduction state of the stroma.Precise coordinate regulation of the electron transport processes and carbon assimilation is an essential feature of photosynthesis. Coordinate regulation in vivo acts to reconcile the conflicting requirements of these processes (4,8,9,16). The enzymes of the carbon reduction cycle require adequate levels of ATP and NADPH to drive carbon assimilation, whereas the electron transport system will only operate efficiently if NADP and ADP are plentiful; hence, the dilemma that must be resolved by precise coordinate control (4,8,9).Concepts of coordinate control of the electron transport processes and the carbon reduction cycle have frequently been derived from a knowledge of the discrete regulatory properties of each individual reaction sequence. Only recently has it been acknowledged that in vivo regulation is much more complex and refined than might be expected from in vitro measurements of individual components of the overall process (4, 8). Physiological events may be reproduced in reconstituted systems, but such systems frequently consist of rather unnatural combinations of components at unph...

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Assimilatory power as a driving force in photosynthesis

Cited by 76 publications

References 32 publications

Combined effects of carbon and phosphorus levels on the invasive cyanobacterium, Cylindrospermopsis raciborskii

Combined effects of carbon and phosphorus levels on the invasive cyanobacterium, Cylindrospermopsis raciborskii

The acclimation response to high light is initiated within seconds as indicated by upregulation of AP2/ERF transcription factor network inArabidopsis thaliana

Control of the Quantum Efficiencies of Photosystems I and II, Electron Flow, and Enzyme Activation following Dark-to-Light Transitions in Pea Leaves

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