In vivo photosynthetic electron transport does not limit photosynthetic capacity in phosphate-deficient sunflower and maize leaves

1993 ◽  
Vol 16 (7) ◽  
pp. 785-795 ◽  
Author(s):  
J. JACOB ◽  
D. W. LAWLOR
Keyword(s):  
Electron Transport ◽  
Photosynthetic Capacity ◽  
Photosynthetic Electron Transport ◽  
Maize Leaves

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.

The Phycobihproteids in Cyanophora paradoxa as Accessoric Pigments and Nitrogen Storage Proteins

1983 ◽  
Vol 38 (11-12) ◽  
pp. 972-977 ◽  
Author(s):  
Hainfried E. A. Schenk ◽  
Jürgen Hanf ◽  
Margarete Neu-Müller
Keyword(s):  
Electron Transport ◽  
Stress Proteins ◽  
Nitrogen Starvation ◽  
Storage Proteins ◽  
Photosynthetic Electron Transport ◽  
Lower Degree ◽  
Nitrogen Storage ◽  
Cyanophora Paradoxa ◽  
Free Living

The phycobiliproteids of cyanobacteria have two functions. They are accessoric pigments for the light-dependent photosynthetic electron transport, and, secondly, they are storage proteins. Cyanocyta korschikoffiana, the endocyanelle of Cyanophora paradoxa, a hardly adapted endocytobiotic cyanobacterium, is responsible for the photoautotrophy of the host flagellate. The biosynthesis of the phycobiliproteids takes place in the endocyanelles and is reversible. Under nitrogen starvation the phycobiliproteids were disintegrated again, in contrast to the carotenoids (and in a lower degree to chlorophyll), whose contents rem ain more constant in the cells, as shown by in vivo measurements. Therefore, it is concluded that sim ilar to the function in free living cyanobacteria the phycobiliproteids of C. paradoxa also serve as storage substances (“stress proteins”). This opinion is supported by experiments with chloramphenicol

Metribuzin-Resistant Mutants of Chlamydomonas reinhardii

1984 ◽  
Vol 39 (5) ◽  
pp. 437-439 ◽  
Author(s):  
N. Pucheu ◽  
W. Oettmeier ◽  
U. Heisterkamp ◽  
K. Masson ◽  
G.F. Wildner
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Wild Type ◽  
Binding Studies ◽  
Molecular Weight Range ◽  
Chlamydomonas Reinhardii ◽  
Thylakoid Membrane Proteins ◽  
Mutant Strains ◽  
Resistant Mutants

Herbicide resistance in Chlamydomonas reinhardii cells was induced by mutagenesis with 5-fluorodeoxyuridine and ethylmethanesulfonate. Four mutant strains were isolated and analyzed for resistance against DCMU-type or phenolic inhibitors of photosynthetic electron transport. The mutants were different in both the extent and the pattern of their resistance: the R/S value, i.e. the ratio of I50 values of the inhibition of photosynthetic electron transport in isolated resistant and susceptible thylakoids, varied for metribuzin from 10 000 to 36. The mutant MZ-1 was resistant against metribuzin, atrazine and DCMU, whereas the mutant MZ-2 showed resistance mainly against metribuzin and atrazine. The mutant MZ-3 was similar to MZ-1, but showed a lesser extent of resistance against DCMU. The mutant MZ-4 showed resistance against metribuzin, but not against atrazine. These results demonstrate that the resistance against one herbicide of the DCMU-type (metribuzin) must not be accompanied by similar resistance against te other inhibitors. Binding studies with radioactively labeled herbicides, [14C]metribuzin, [14C]atrazine and [3H]DCMU, and isolated thylakoids supported these observations. Phosphorylation of thylakoid membrane proteins was studied with wild-type cells and resistant mutants under in vivo conditions in the light. The 32P-labeled main proteins bands were in the molecular weight range of 10-14 kDa, 26-29 kDa, 32-35 kDa and 46-48 kDa. The pattern and the extent of incorporation of 32P were similar for the mutants and the wild-type cells.

On the Mechanism of Benzoquinone Penetration and Photoreduction by Whole Cells

1971 ◽  
Vol 26 (6) ◽  
pp. 585-588 ◽  
Author(s):  
H. Gimmler ◽  
M. Avron
Keyword(s):  
Electron Transport ◽  
Cell Membrane ◽  
Photosynthetic Electron Transport ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Porphyridium Cruentum ◽  
Whole Cells ◽  
Time Treatment ◽  
Short Time

Short time treatment of intact Porphyridium cruentum cells with benzoquinone results in changes of the cell membranes, which lead to a higher permeability. This increased permeability allows the measurements of photosynthetic electron transport reactions with various electron donors, ac. ceptors and mediators, which cannot enter untreated cells. The capacity of benzoquinone to act as a Hill - reagent in vivo is interpreted as due to a double action of this compound: changing the permeability of the cells by reacting with the cell membrane coupled with the ability of the unreacted molecules to serve as electron acceptors.

Photoautotrophic Chenopodium rubrum Cell Suspension Cultures Resistant against Photosynthesis-Inhibiting Herbicides II. Physiological and Biochemical Properties

1994 ◽  
Vol 49 (11-12) ◽  
pp. 791-801 ◽  
Author(s):  
Jutta Thiemann ◽  
Wolfgang Barz
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll Content ◽  
Photosynthetic Capacity ◽  
Growth Parameters ◽  
Cell Suspension Cultures ◽  
Photosynthetic Electron Transport ◽  
Cell Number ◽  
Biochemical Properties ◽  
Chenopodium Rubrum

Eight photoautotrophic cell cultures of Chenopodium rubrum, which are resistant against the photosystem II inhibitor metribuzin, were characterized for their growth parameters, chlorophyll content and photosynthetic capacity. Herbicide resistance of the eight lines results from different mutations in the D 1 protein of photosystem II, which is the target for different photosystem II inhibitors. In the presence of 10-5 ᴍ metribuzin the eight lines showed substantial growth reduction depending on the degree of resistance, and this effect is explained by a reduced electron transport in photosystem II. The impaired photosynthetic capacity of the green cells in the presence of high metribuzin concentrations, leads to compensation effects similar to shade accommodation of plants. Adaptation includes an increase of the chlorophyll content, a decrease of the chlorophyll a/b ratios as well as an increase of thylakoid stacking and cell number per unit fresh weight. In the absence of the herbicide photosynthetic electron transport is not impaired, as indicated by measurements of electron transfer rates in photosystem II and flash-induced reduction kinetics of P-700+. In summary the alterations of the D 1 protein of the eight cell lines do not result in a reduced electron transport in photosystem II.

Multiple in vivo Effects of Cadmium on Photosynthetic Electron Transport in Pea Plants

2021 ◽  
Author(s):  
Daria Todorenko ◽  
Alena Volgusheva ◽  
Nyurgun Timofeev ◽  
Ilya Kovalenko ◽  
Dmitry Matorin ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
In Vivo Effects

Research note: Energy partitioning in photosystem II complexes subjected to photoinhibitory treatment

2007 ◽  
Vol 34 (3) ◽  
pp. 214 ◽  
Author(s):  
Dmytro Kornyeyev ◽  
Luke Hendrickson
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Photosynthetic Electron Transport ◽  
Energy Partitioning ◽  
Simple Equations

Chlorophyll a fluorescence measured in vivo is frequently used to study the role of different processes influencing the distribution of excitation energy in PSII complexes. Such studies are important for understanding the regulation of photosynthetic electron transport. However, at the present time, there is no unified methodology to analyse the energy partitioning in PSII. In this article, we critically assess several approaches recently developed in this area of research and propose new simple equations, which can be used for de-convolution of non-photochemical energy quenching in PSII complexes.

Sign in / Sign up

Export Citation Format

Share Document