GENERAL FEATURES OF PHOTOPROTECTION BY ENERGY DISSIPATION IN PLANKTONIC DIATOMS BACILLARIOPHYCEAEReport as inadecuate




GENERAL FEATURES OF PHOTOPROTECTION BY ENERGY DISSIPATION IN PLANKTONIC DIATOMS BACILLARIOPHYCEAE - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 LIENSs - LIttoral ENvironnement et Sociétés - UMR 7266 2 CNRS - Centre National de la Recherche Scientifique

Abstract : Planktonic diatoms Bacillariophyceae have to cope with large fluctuations of light intensity and periodic exposure to high light. After a shift to high light, photoprotective dissipation of excess energy characterized by the non-photochemical quenching of fluorescence NPQ and the concomitant de-epoxidation of diadinoxanthin to diatoxanthin DT were measured in four different planktonic marine diatoms Bacillariophyceae: Skeletonema costatum Greville Cleve, Cylindrotheca fusiformis Reimann et Lewin, Thalassiosira weissflogii Grunow Fryxell et Hasle and Ditylum brightwellii West Grunow in comparison to the model organism Phaeodactylum tricornutum Böhlin. Upon a sudden increase of light intensity, de-epoxidation was rapid and de novo synthesis of DT also occurred. In all species, NPQ was linearly related to the amount of DT formed during high light. In this report, we focused on the role of DT in the dissipation of energy which takes place in the LHC. In S. costatum for the same amount of DT, less NPQ was formed than in P. tricornutum and as a consequence the photoprotection of PS II was less efficient. The general features of photoprotection by harmless dissipation of excess energy in planktonic diatoms described here partly explain why diatoms are well adapted to light intensity fluctuations.





Author: Johann Lavaud - Bernard Rousseau Anne-Lise Etienne

Source: https://hal.archives-ouvertes.fr/



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