Chlorophyll fluorescence in the evaluation of photosynthetic electron transport chain inhibitors in the pea

Marcio Espinosa Farias,Marcos Antonio Bacarin,Emanuela Garbin Martinazzo

doi:10.5935/1806-6690.20160021

Marcio Espinosa Farias, Marcos Antonio Bacarin + Show 1 more

Open Access

https://doi.org/10.5935/1806-6690.20160021

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Abstract

The study aimed to evaluate the behavior of the chair of photosynthetic electron transport in the presence of DCMU and atrazine in detached leaves of pea through simultaneous measurements of the kinetics of fluorescence transient, fluorescence delayed and modulated reflection at 820 nm. The petioles of the leaves were immersed for two hours in solution of inhibitors at concentrations of 0 (control), 25, 50, 100, 250 and 500 µM. Measurements of the kinetics of fluorescence transient and fluorescence delayed and modulated reflection at 820 nm were recorded simultaneously by the M-PEA fluorometer. Simultaneous measurement of fluorescence transient, fluorescence delayed and modulated 820 nm reflection is important for assessments of the photosynthetic electron transport chain activity tool. The use of specific inhibitors of the electron transport chain allows you to collect and correlate a lot of information about the effect of different inhibitors at specific points in the photosynthetic electron transport chain. DCMU and atrazine are inhibitors of photosystem II and the concentration of 500 mM affects more strongly the flow of photosynthetic electrons.

Highlights

The study aimed to evaluate the behavior of the chair of photosynthetic electron transport in the presence of DCMU and atrazine in detached leaves of pea through simultaneous measurements of the kinetics of fluorescence transient, fluorescence delayed and modulated reflection at 820 nm
When the plants presented young and fully expanded leaves, they were taken to the laboratory, where the leaves were detached with the aid of scissors, and the petiole immediately immersed in a 10 ml solution of each inhibitor [DCMU (3-(3’,4’-dichlorophenyl)-1,1dimethylurea) and atrazine (2-chloro-4-ethylamino-6isoproprilano s-triazine)]
The Chl a fluorescence transient, represented on a logarithmic time scale starting at 50 μS, shows an increase in the level of J as the concentrations of DCMU increase (Figures 1A and 1C)

Summary

Introduction

The study aimed to evaluate the behavior of the chair of photosynthetic electron transport in the presence of DCMU and atrazine in detached leaves of pea through simultaneous measurements of the kinetics of fluorescence transient, fluorescence delayed and modulated reflection at 820 nm. Measurements of the kinetics of fluorescence transient and fluorescence delayed and modulated reflection at 820 nm were recorded simultaneously by the M-PEA fluorometer. RESUMO - O trabalho teve como objetivo avaliar o comportamento da cadeia de transporte de elétrons fotossintética na presença de DCMU e atrazina, em folhas destacadas de ervilha, através de medidas simultâneas das cinéticas da fluorescência transiente, decaída da fluorescência da clorofila a e reflexão modulada a 820 nm. A medida simultânea da fluorescência transiente, decaída da fluorescência e reflexão modulada a 820 nm é ferramenta importante para avaliações da atividade da cadeia de transporte de elétrons fotossintética. The electron transport chain (ETC) is made up of protein complexes embedded in the thylakoid membrane

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