Radical Pair Quantum Yield in Reaction Centers of Photosystem II of Green Plants and of the BacteriumRhodobacter sphaeroides. Saturation Behavior with Sub-picosecond Pulses

1997 ◽  
Vol 101 (39) ◽  
pp. 7869-7873 ◽  
Author(s):  
Marie-Louise Groot ◽  
Rienk van Grondelle ◽  
Jan-Adriaan Leegwater ◽  
Frank van Mourik
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Radical Pair ◽  
Reaction Centers ◽  
Picosecond Pulses ◽  
Green Plants

scholarly journals Similarity of primary radical pair recombination in photosystem II and bacterial reaction centers

FEBS Letters ◽  
1993 ◽  
Vol 336 (2) ◽  
pp. 357-362 ◽  
Author(s):  
Martin Volk ◽  
Matthias Gilbert ◽  
Gerhard Rousseau ◽  
Martin Richter ◽  
Alexander Ogrodnik ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Radical Pair ◽  
Reaction Centers ◽  
Primary Radical ◽  
Bacterial Reaction Centers ◽  
Primary Radical Pair

scholarly journals Changes in Light Energy Utilization in Photosystem II and Reactive Oxygen Species Generation in Potato Leaves by the Pinworm Tuta absoluta

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2984
Author(s):  
Ilektra Sperdouli ◽  
Stefanos Andreadis ◽  
Julietta Moustaka ◽  
Emmanuel Panteris ◽  
Aphrodite Tsaballa ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Reaction Centers ◽  
Oxygen Species ◽  
Imaging Analysis ◽  
Psii Photochemistry ◽  
Before And After ◽  
Leaf Level ◽  
Feeding Zone

We evaluated photosystem II (PSII) functionality in potato plants (Solanum tuberosum L.) before and after a 15 min feeding by the leaf miner Tuta absoluta using chlorophyll a fluorescence imaging analysis combined with reactive oxygen species (ROS) detection. Fifteen minutes after feeding, we observed at the feeding zone and at the whole leaf a decrease in the effective quantum yield of photosystem II (PSII) photochemistry (ΦPSII). While at the feeding zone the quantum yield of regulated non-photochemical energy loss in PSII (ΦNPQ) did not change, at the whole leaf level there was a significant increase. As a result, at the feeding zone a significant increase in the quantum yield of non-regulated energy loss in PSII (ΦNO) occurred, but there was no change at the whole leaf level compared to that before feeding, indicating no change in singlet oxygen (1O2) formation. The decreased ΦPSII after feeding was due to a decreased fraction of open reaction centers (qp), since the efficiency of open PSII reaction centers to utilize the light energy (Fv′/Fm′) did not differ before and after feeding. The decreased fraction of open reaction centers resulted in increased excess excitation energy (EXC) at the feeding zone and at the whole leaf level, while hydrogen peroxide (H2O2) production was detected only at the feeding zone. Although the whole leaf PSII efficiency decreased compared to that before feeding, the maximum efficiency of PSII photochemistry (Fv/Fm), and the efficiency of the water-splitting complex on the donor side of PSII (Fv/Fo), did not differ to that before feeding, thus they cannot be considered as sensitive parameters to monitor biotic stress effects. Chlorophyll fluorescence imaging analysis proved to be a good indicator to monitor even short-term impacts of insect herbivory on photosynthetic function, and among the studied parameters, the reduction status of the plastoquinone pool (qp) was the most sensitive and suitable indicator to probe photosynthetic function under biotic stress.

Does Slow Energy Transfer Limit the Observed Time Constant for Radical Pair Formation in Photosystem II Reaction Centers?

Biochemistry ◽  
1994 ◽  
Vol 33 (49) ◽  
pp. 14768-14774 ◽  
Author(s):  
Thomas Rech ◽  
James R. Durrant ◽  
D. Melissa Joseph ◽  
James Barber ◽  
George Porter ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Photosystem Ii ◽  
Time Constant ◽  
Radical Pair ◽  
Pair Formation ◽  
Reaction Centers

Modulation of Quantum Yield of Primary Radical Pair Formation in Photosystem II by Site-Directed Mutagenesis Affecting Radical Cations and Anions†

Biochemistry ◽  
1998 ◽  
Vol 37 (50) ◽  
pp. 17439-17447 ◽  
Author(s):  
Stephen A. P. Merry ◽  
Peter J. Nixon ◽  
Laura M. C. Barter ◽  
Maria Schilstra ◽  
George Porter ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Radical Pair ◽  
Radical Cations ◽  
Pair Formation ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Primary Radical ◽  
Primary Radical Pair

scholarly journals Nitrogen and Phosphorus Addition to Soil Improves Seed Yield, Foliar Stomatal Conductance, and the Photosynthetic Response of Rapeseed (Brassica napus L.)

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 483
Author(s):  
Esmaeil Zangani ◽  
Kamran Afsahi ◽  
Farid Shekari ◽  
Eileen Mac Sweeney ◽  
Andrea Mastinu
Keyword(s):  
Stomatal Conductance ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Chlorophyll Content ◽  
Seed Yield ◽  
Nitrogen Application ◽  
Flowering Stage ◽  
Nitrogen And Phosphorus ◽  
Brassica Napus L ◽  
Phosphorus Levels

The effects of nitrogen and phosphorus levels on the physiological traits, yield, and seed yield of rapeseed (Brassica napus L.), were studied in a farm research project of Zanjan University. Three levels of nitrogen (0, 100, and 200 kg/ha) and three levels of phosphorus (0, 75, and 150 kg/ha) were considered. The results showed that an increase in nitrogen level caused an increase in the leaf chlorophyll content so that the application of 200 kg/ha of nitrogen increased the chlorophyll content of the leaves until the mid-grain filling stage. Nitrogen application lowered leaf stomatal conductance in the early flowering stage whereas the stomatal conductance was increased during the late flowering stage. Nitrogen application (100 and 200 kg/ha) also increased the quantum yield of photosystem II. On the other hand, with the application of 150 kg/ha and 75 kg/ha of phosphorus, the leaf stomatal conductance and the quantum yield of photosystem II in the early flowering stage increased respectively. The results showed that the application of 200 kg/ha of nitrogen and 75 kg/ha of phosphorus significantly increased seed and oil yield compared to the control. In addition, the number of siliques per plant and the weight of 1000 seeds showed an increasing trend that was affected by nitrogen and phosphorus levels. This study demonstrated that nitrogen enhanced the chlorophyll content, leaf area, and consequently, the quantum yield of photosystem II. Nitrogen also augmented the seed filling duration, seed yield, and oil yield by increasing gas exchange. As a result, the application of 100 kg/ha of nitrogen together with 75 kg/ha phosphorus showed the greatest effect on the qualitative and quantitative yield of rapeseed. However, the application of 200 kg/ha of nitrogen alone or in combination with different levels of phosphorus did not significantly increase many of the studied traits.

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