Evaluation of relative contribution of initial and variable chlorophyll fluorescence measured at different temperatures

Title:

Evaluation of relative contribution of initial and variable chlorophyll fluorescence measured at different temperatures

Creator:

Goltsev, V., Yordanov, I., and Tsonev, T.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:305ed0a1-8353-4236-a259-e44f1f9c5a52
uuid:305ed0a1-8353-4236-a259-e44f1f9c5a52
urnnbn:urn:nbn:cz:aba007-000fmd

Type:

model:internalpart and TEXT

Format:

print

Description:

The temperature dependence of the induction kinetics parameters of chiorophyll (Chl) fluorescence in leaves and isolated chloroplasts of young plants of PhaseoliLt vulgaris L. was studied. Theoretical prerequisites for the influence of fluorescence measuring temperature as well as 3 min pretreatment of leaf discs cn both the photophysical and dark processes in the photosynthetic appaiatus were evaluated. The registration manner of fluorescence kinetics detennined the pattem of temperature dependence curve. The characteristic temperature of sharp changes of induction kinetics parameters, maximal and initial fluorescence and Fq, were in ranges of 45-47 and 55-60 °C, respectively. The fitting of experimental data from thermograms registered at weak exciting iiradiance in thermoinactivated leaf discs allowed to estimate the activation energy (FJ of the intemal energy conversion process in excited Chl molecule as 51.2±0.15 kJ moTT The theoretical analysis of /'q measured by a PAM fluorometer showed that Fq registered even at low inadiances markedly exceeded its ideál dark value. The Fq measured at 25 °C was increased by 125±5.3 % by the herbicide DCMU and diminished by -23.8±1.6 % by the elechon acceptor DCBQ. At the experimental conditions ušed there were about 25 % of 1\ from dosed Qg non-reducing reaction centres in the measured Fq value. Thus the thermoinduced increase in Fq observed within the temperature inteiwal of 45-50 °C might be doně by a transition of PS2 reaction centres from a statě capable of reducing Q3 to a Qg-non-reducing statě.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

629-643 and 151-165

Source:

Photosynthetica | 1994 Volume:30 | Number:4

Harvested from:

CDK

Metadata only:

false