The relationship between CO2 assimilation and electron transport in leaves

1990 ◽  
Vol 25 (3) ◽  
pp. 213-224 ◽  
Author(s):  
Jeremy Harbinson ◽  
Bernard Genty ◽  
Neil R. Baker
Keyword(s):  
Electron Transport ◽  
Co2 Assimilation ◽  
The Relationship

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.

Environmental Effects on the Relationship Between the Quantum Yields of Carbon Assimilation and in vivo PsII Electron Transport in Maize

1991 ◽  
Vol 18 (3) ◽  
pp. 267 ◽  
Author(s):  
JP Krall ◽  
GE Edwards
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
High Energy ◽  
Co2 Assimilation ◽  
Quantum Yields ◽  
Photon Flux ◽  
Ps Ii ◽  
C4 Species ◽  
The Relationship

The partitioning of light energy absorbed by photosystem (PS) II in the C4 species maize was investigated under various photosynthetic photon flux densities (PPFD), temperatures, and intercellular CO2 concentrations. The relationship between the quantum yield of PSII electron transport (�e) and the quantum yield of CO2 assimilation (ΦCO2) was generally found to be linear, with similar slopes. This indicates that PSII electron transport is tightly coupled to CO2 assimilation such that measurements of �e may be used to estimate photosynthetic rates in maize. Coefficients of quenching of PSII chlorophyll fluorescence indicated that, under excessive PPFD or when CO2 assimilation was decreased due to suboptimal or supraoptimal temperature or low Ci, the energy in excess of that needed to drive the reduced rate of PSII electron transport was dissipated via a mechanism known to be correlated to the trans-thylakoid proton gradient (high energy quenching, qE) and a mechanism believed to arise in the PSII antenna chlorophyll (qN(slow)). At suboptimal temperature the energy dissipation was principally at the antenna level and qE was low, while at supraoptimal temperature the reverse was true. The results are discussed relative to coupling of PSII activity to CO2 fixation and mechanisms of energy dissipation in this C4 species.

Acclimation by the Thylakoid Membranes to Growth Irradiance and the Partitioning of Nitrogen Between Soluble and Thylakoid Proteins

1988 ◽  
Vol 15 (2) ◽  
pp. 93 ◽  
Author(s):  
JR Evans
Keyword(s):  
Electron Transport ◽  
High Efficiency ◽  
Co2 Assimilation ◽  
Thylakoid Membranes ◽  
Leaf Nitrogen ◽  
Cytochrome F ◽  
Leaf Nitrogen Content ◽  
Carboxylase Activity ◽  
The Relationship ◽  
Shade Plants

Three characteristics of shade plants are reviewed. Firstly, they have relatively more chlorophyll b and the associated light-harvesting chlorophyll a/b-protein complex (LHC). Two currently accepted reasons for this are not supported by quantitative analysis. Instead, the reduced protein cost of complexing chlorophyll in LHC and the turnover of the 32 kDa herbicide binding protein are considered. Secondly, shade plants have low electron transport capacities per unit of chlorophyll. This is primarily related to a reduction in the amount of electron transport components such as the cytochrome f complex and the ATPase. The nitrogen cost of the thylakoid membranes per unit of light absorbed is thereby reduced, but the irradiance range over which light is used with high efficiency is also reduced. Thirdly, shade plants have less RuP2 carboxylase and other soluble proteins for a given amount of chlorophyll. However, while the ratio of RuP2 carboxylase protein to thylakoid protein declined, the ratio of the RuP2 carboxylase activity to electron transport activity increased. For several species, the relationship between the rate of CO2 assimilation and leaf nitrogen content depends on the irradiance during growth.

On the Relationship Between Electron Transport Rate and Photosynthesis in Leaves of the C4 Plant Sorghum bicolor Exposed to Water Stress, Temperature Changes and Carbon Metabolism Inhibition

1995 ◽  
Vol 22 (6) ◽  
pp. 885 ◽  
Author(s):  
F Loreto ◽  
D Tricoli ◽  
GD Marco
Keyword(s):  
Water Stress ◽  
Electron Transport ◽  
Sorghum Bicolor ◽  
Carbon Metabolism ◽  
Sweet Sorghum ◽  
Co2 Assimilation ◽  
Linear Electron ◽  
Reaction Centres ◽  
Metabolism Inhibition ◽  
The Relationship

We examined the effect of carbon metabolism inhibition, temperature, and water stress on the relationship between the linear electron transport and photosynthetic CO2 assimilation in sweet sorghum, Sorghum bicolor (L.) Moench. Carbon metabolism was inhibited either by removing CO2 from the air or by feeding glyceraldehyde to the leaves. Irrespective of the method used, the linear electron transport and photosynthesis were coordinately inhibited. However, when photosynthesis was totally inhibited, a residual electron transport between 20 and 35 μmol m-2 s-1 could be measured. The residual electron transport increased with increasing leaf temperature up to 38�C and was higher in water-stressed leaves than in control leaves. Temperature affected photosynthesis in intact leaves. The optimal temperature for photosynthesis in control leaves was between 30 and 35�C. The ratio between linear electron transport and photosynthesis showed a temperature dependency similar to that of photosynthesis. As a consequence, the electrons required to fix one mole of CO2 were 5.5 at suboptimal temperatures but were 6.5 at 30�C. Our results indicate that the relationship between linear electron transport and photosynthesis is not perfectly steady in nature but is subject to transient changes. The observed changes in the linear electron transport were mostly related to changes in the efficiency of light trapping by open photosystem II (PSII) reaction centres, while the fractions of open PSII reaction centres were relatively constant during the experiment. Water stress severely reduced the photosynthetic CO2 assimilation of sweet sorghum leaves. The greater the water stress, the lower the temperature at which optimal photosynthesis was reached. The linear electron transport was coordinately inhibited by water stress but a residual electron transport was again found when photosynthesis was extremely reduced by water stress. Under water-stress conditions the fraction of PSII reaction centres in an open state was very low but constant, and the temperature dependent reduction of linear electron transport was caused by the reduction of the efficiency of energy capture of PSII reaction centres.

Compensation for PSII Photoinactivation by Regulated Non-photochemical Dissipation Influences the Impact of Photoinactivation on Electron Transport and CO2 Assimilation

2006 ◽  
Vol 47 (4) ◽  
pp. 437-446 ◽  
Author(s):  
Dmytro Kornyeyev ◽  
Barry A. Logan ◽  
David T. Tissue ◽  
Randy D. Allen ◽  
A. Scott Holaday
Keyword(s):  
Electron Transport ◽  
Co2 Assimilation ◽  
The Impact

scholarly journals ATP Synthase Repression in Tobacco Restricts Photosynthetic Electron Transport, CO2 Assimilation, and Plant Growth by Overacidification of the Thylakoid Lumen

2011 ◽  
Vol 23 (1) ◽  
pp. 304-321 ◽  
Author(s):  
Markus Rott ◽  
Nádia F. Martins ◽  
Wolfram Thiele ◽  
Wolfgang Lein ◽  
Ralph Bock ◽  
...  
Keyword(s):  
Electron Transport ◽  
Plant Growth ◽  
Atp Synthase ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
Thylakoid Lumen

scholarly journals Changes in Agronomic and Physiological Traits of Sugarcane Grown with Saline Irrigation Water

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 722
Author(s):  
Kenta Watanabe ◽  
Hiroo Takaragawa ◽  
Masami Ueno ◽  
Yoshinobu Kawamitsu
Keyword(s):  
Salt Concentration ◽  
Irrigation Water ◽  
Stomatal Closure ◽  
Co2 Assimilation ◽  
Physiological Traits ◽  
Sugar Concentration ◽  
Saline Irrigation ◽  
Saccharum Spp ◽  
The Relationship ◽  
Harmful Effects

In Japan, the highest salt concentration in irrigation water for sugarcane cultivation has been reported to be above 2500 mg L−1, which may cause harmful effects to the crops; however, little information is available on the relationship between the salinity of irrigation water and sugarcane. To investigate its effects on agronomic and physiological traits, a Japanese cultivar, Saccharum spp cv. NiF8, was grown with 0, 200, 500, 1000, 2000, and 3000 mg NaCl L−1 under pot conditions. The treatments significantly lowered leaf area; however, NaCl levels up to 500 mg L−1 did not greatly reduce culm weight and juice sugar concentration. These traits were impaired when the tested cultivar was grown with 1000 mg NaCl L−1 or higher, indicating that salt concentration is desired to be lower than 1000 mg L−1. CO2 assimilation rate was inhibited mainly due to stomatal closure caused by salt stress. The treatments significantly altered Na+, Cl−, and K+ concentrations in juice but not those in leaf, suggesting that juice analysis is an effective method to estimate its salinization status. Culm weight and juice sugar concentration were severely affected as juice conductivity exceeded 900 mS m−1; thereby, sugarcane plants of NiF8 possessing conductivity above this level could be considered salt-stressed where water salinity is a concern.

The relationship between the activation state of sucrose-phosphate synthase and the rate of CO2 assimilation in spinach leaves

Planta ◽  
1991 ◽  
Vol 183 (4) ◽  
Author(s):  
Alberto Battistelli ◽  
MichaelD. Adcock ◽  
RichardC. Leegood
Keyword(s):  
Sucrose Phosphate Synthase ◽  
Co2 Assimilation ◽  
The Relationship ◽  
Sucrose Phosphate ◽  
Spinach Leaves ◽  
Phosphate Synthase
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