Heat-induced changes of chlorophyll fluorescence in intact leaves correlated with damage of the photosynthetic apparatus

Planta ◽  
1977 ◽  
Vol 136 (3) ◽  
pp. 233-238 ◽  
Author(s):  
Ulrich Schreiber ◽  
Joseph A. Berry
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Apparatus ◽  
Intact Leaves ◽  
Induced Changes

DROUGHT-INDUCED CHANGES IN CHLOROPHYLL FLUORESCENCE OF YOUNG BEAN PLANTS

2010 ◽  
Vol II (4) ◽  
pp. 75-79 ◽  
Author(s):  
Zlatko Zlatev ◽  
Andon Vassilev ◽  
Vasilii Goltsev ◽  
Georgi Popov
Keyword(s):  
Chlorophyll Fluorescence ◽  
Bean Plants ◽  
Induced Changes

scholarly journals A commonly used photosynthetic inhibitor fails to block electron flow to photosystem I in intact systems

2019 ◽  
Author(s):  
Duncan Fitzpatrick ◽  
Eva-Mari Aro ◽  
Arjun Tiwari
Keyword(s):  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Intact Cells ◽  
Membrane Inlet Mass Spectrometry ◽  
Redox Kinetics ◽  
Species Formation ◽  
Intact Leaves ◽  
Transfer Chain ◽  
Photosynthetic Electron Transfer

AbstractIn plant science, 2,4-dinitrophenylether of iodonitrothymol (DNP-INT) is frequently used as an alternative to 2,5-dibromo-6-isopropyl-3-methyl-1,4-benzoquinone (DBMIB) to examine the capacity of plastoquinol and semiquinone to reduce O2. DNP-INT is considered an effective inhibitor of the photosynthetic electron transfer chain (PETC) through its binding at the Q0 site of Cyt-b6f. The binding and action of DNP-INT has been previously characterized spectroscopically in purified Cyt-b6f complex reconstituted with Plastocyanin, PSII membranes and plastoquinone, as well as in isolated thylakoids based on its property to block MV-mediated O2 consumption. Contrary to the conclusions made from these experiments, we observed clear reduction of P700+ in samples incubated with DNP-INT during our recent investigation into the sites of oxygen consumption in isolated thylakoids. Therefore, we carried out an extensive investigation of DNP-INT’s chemical efficacy in isolated thylakoids and intact leaves. This included examination of its capacity to block the PETC before PSI, and therefore its inhibition of CO2 fixation. P700 redox kinetics were measured using Dual-PAM whilst Membrane Inlet Mass Spectrometry (MIMS) was used for simultaneous determination of the rates of O2 evolution and O2 consumption in isolated thylakoids and CO2 fixation in intact leaves, using two stable isotopes of oxygen (16O2,18O2) and CO2 (12C,13C), respectively. Based on these investigations we confirmed that DNP-INT is unable to completely block the PETC and CO2 fixation, therefore its use may produce artefacts if applied to isolated thylakoids or intact cells, especially when determining the locations of reactive oxygen species formation in the photosynthetic apparatus.

In vitro selection of microspores for resistance to oxidative stress resulted in chilling tolerance in doubled haploid maize lines

2011 ◽  
Vol 59 (3) ◽  
pp. 209-216
Author(s):  
Eva Darkó ◽  
H. Ambrus ◽  
A. Szenzenstein ◽  
B. Barnabás
Keyword(s):  
Oxidative Stress ◽  
Electron Transport ◽  
Antioxidant Capacity ◽  
Doubled Haploid ◽  
Chilling Stress ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Chilling Tolerance ◽  
Chlorophyll Breakdown ◽  
Induced Changes

The chilling tolerance of doubled haploid (DH) maize plants selected and regenerated from microspores exposed to prooxidants, paraquat or tert-butyl hydroperoxide was determined by monitoring cold-induced changes in the photosynthetic electron transport, CO2 assimilation processes and chlorophyll breakdown in young leaves after cold treatment (8°C for 5 days). The results were compared to those of the non-selected DH line and the original hybrid plants. Chilling stress caused a great reduction in the Fv/Fm, qP and ΔF/Fm’ fluorescence parameters, related to the photosynthetic electron transport processes, and in carbon assimilation, and resulted in chlorophyll breakdown. These changes were less extensive in the selected DH plants, which showed elevated antioxidant capacity both at ambient and at low temperature. Among the antioxidant enzymes tested, the activity of GR and GST was induced by chilling stress to the greatest extent. Correlations between cold-induced changes in the photosynthetic apparatus and the antioxidant capacity of the plants suggested that the better protection against oxidative stress induced by the elevated antioxidant capacity of the plants contributed to protecting the photosynthetic apparatus from cold.

scholarly journals Chlorophyll Fluorescence Kinetics May Be Useful to Identify Early Drought and Irrigation Effects on Photosynthetic Apparatus in Field-Grown Wheat

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1275
Author(s):  
Lenka Botyanszka ◽  
Marek Zivcak ◽  
Erik Chovancek ◽  
Oksana Sytar ◽  
Viliam Barek ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Deficit ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Photosynthetic Apparatus ◽  
Optical Methods ◽  
Accurate Information ◽  
Ojip Transient ◽  
Fluorescence Kinetics ◽  
Non Invasive

To assess the reliability and sensitivity of non-invasive optical methods to detect the early effects of water deficit in the field, we analyzed the time-series of non-invasive measurements obtained in a dry season in a representative collection of wheat genotypes grown in small-plot field trials, in non-irrigated and irrigated variants. Despite a progressive water deficit and significant yield loss, the measurements indicated very minor changes in chlorophyll content or canopy cover. This corresponded well to the insignificant differences in spectral reflectance normalized difference vegetation index (NDVI) values. On the other hand, we identified the significant and rapid response of fast fluorescence kinetics data following the onset of irrigation. Analysis of parameters showed the main effects of drought were associated with changes in the amplitude of the I–P phase of the OJIP transient, indicating changes at the level of photosystem I and beyond. Statistical analyses identified the integrative parameter performance index PItot as the most sensitive parameter, which well-reflects the differences in responses of the genotypes to water deficit. Our results suggest that focusing on photosynthetic functions detected by the rapid chlorophyll fluorescence records can provide more accurate information on the drought stress level, compared to the structural data obtained by absorbance or reflectance measurements.

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