scholarly journals Quenching of Chlorophyll a Fluorescence in Response to Na+-Dependent HCO3- Transport-Mediated Accumulation of Inorganic Carbon in the Cyanobacterium Synechococcus UTEX 625

1994 ◽  
Vol 104 (2) ◽  
pp. 785-791 ◽  
Author(s):  
C. M. Crotty ◽  
P. N. Tyrrell ◽  
G. S. Espie
1997 ◽  
Vol 75 (6) ◽  
pp. 946-954 ◽  
Author(s):  
Qinglin Li ◽  
David Thomas Canvin

Simultaneous measurements were made of O2 exchange, inorganic carbon (Ci) accumulation and assimilation, and chlorophyll a fluorescence of the cyanobacterium Synechococcus UTEX 625. The addition of Ci to cells at the CO2 compensation point resulted in quenching of chlorophyll a fluorescence in the presence or absence of the CO2 fixation inhibitor, iodoacetamide. The magnitude of quenching was related to electron flow to terminal electron acceptors such as CO2 and O2. When photosynthetic CO2 fixation was allowed, the rate of electron transport, as expressed by (F*m – F)/F*m, was highly correlated with the onset of photosynthesis. When CO2 fixation was inhibited by the addition of iodoacetamide, the observed fluorescence quenching was consistent with the enhanced rate of O2 photoreduction that occurred when Ci was added. There was a close correlation (r = 0.98) between the magnitude of O2-dependent fluorescence quenching and the amount of O2 photoreduction. The degree of stimulation of electron flow to O2 photoreduction was dependent on the inorganic carbon concentration. The K1/2 (Ci) for extracellular Ci was 1.36 ± 0.13 μM (mean ± SD, n = 3) and K1/2 (Ci) for the intracellular Ci pool was 1.4 ± 0.18 mM (mean ± SD, n = 3). The reduction of N,N-dimethyl-p-nitrosoaniline was also stimulated by the addition of Ci, whereas the addition of Ci had no effect on the reduction of 2,6-dimethylbenzoquinone and ferricyanide. The results suggest that Ci stimulates electron flow in photosystem I. Key words: cyanobacteria, O2 photoreduction, fluorescence, Ci concentrating mechanism, inorganic carbon pool, linear electron transport, kinetic study.


2021 ◽  
Vol 262 ◽  
pp. 112482
Author(s):  
Remika S. Gupana ◽  
Daniel Odermatt ◽  
Ilaria Cesana ◽  
Claudia Giardino ◽  
Ladislav Nedbal ◽  
...  

2021 ◽  
Vol 58 ◽  
pp. 102399
Author(s):  
Jason Hupp ◽  
Johnathan I.E. McCoy ◽  
Allen J. Millgan ◽  
Graham Peers

Nature Plants ◽  
2021 ◽  
Author(s):  
Albert Porcar-Castell ◽  
Zbyněk Malenovský ◽  
Troy Magney ◽  
Shari Van Wittenberghe ◽  
Beatriz Fernández-Marín ◽  
...  

2021 ◽  
Author(s):  
Hussan Bano ◽  
Habib‐ur‐Rehman Athar ◽  
Zafar Ullah Zafar ◽  
Hazem M. Kalaji ◽  
Muhammad Ashraf

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.


2011 ◽  
Vol 9 (2) ◽  
pp. 291-295 ◽  
Author(s):  
Ilona Czyczyło-Mysza ◽  
Izabela Marcińska ◽  
Edyta Skrzypek ◽  
Małgorzata Chrupek ◽  
Stanisław Grzesiak ◽  
...  

Drought is one of the major factors limiting wheat yield in many developing countries worldwide. Parameters of chlorophyll a fluorescence kinetics under drought stress conditions have been used to characterize dehydration tolerance in wheat. In the present study, a set of 94 doubled haploid lines obtained from Chinese Spring × SQ1 (CSDH), mapped with 450 markers, was evaluated for yield (grain dry weight/main stem ear), number of grains/main stem ear (NG) and chlorophyll a fluorescence parameters (FC) under moderate and severe drought stress, and compared with results for well-watered plants. quantitative trait loci (QTLs) were identified using Windows QTLCartographer version 2.5 software and the results were analysed using single-marker analysis (SMA) and composite interval mapping (CIM). Analysis using SMA and CIM showed mostly similar QTLs for all traits, though more QTLs were identified by SMA than by CIM. The genetic control of yield, NG and FC varied considerably between drought-stressed and non-stressed plants. Although no major QTL co-locations were found for yield and FC using CIM, the co-location of QTLs for NG, yield and Fv/Fm in drought-stressed plants was observed on chromosome 5A using SMA.


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