Roles of LESIONS SIMULATING DISEASE 1 and Salicylic acid in Acclimation of Plants to Environmental Cues Redox homeostasis and physiological processes underlying plants responses to biotic and abiotic challenges

P.1 ABBREVIATIONS – P.2 LIST OF PAPERS – P.5 INTRODUCTION. 1 The photosynthetic processes – P.7 1.1 Light reactions. 1.2 Carbon reactions. 2 Regulation of photosynthetic processes – P.8 2.1 Non photochemical dissipation mechanisms. 2.2 Photochemical dissipation mechanisms. 3 Reactive oxygen species (ROS) and antioxidant system – P.11 3.1 ROS production sites and homeostasis. 3.2 Low molecular weight antioxidants. 3.3 Enzymatic antioxidant system. 4 The lesion simulated disease 1 (lsd1) mutant – P.14 5 Motivation of this work – P.15 RESULTS AND DISCUSSION. 6 Runaway cell death in lsd1 is triggered when components of the photosynthetic electron transport are reduced – P.16 6.1 rcd correlated to PSII activity. 6.2 rcd correlated to the redox status of the PQ pool. 7 Role of photorespiration and stomatal conductance in the rcd – P.18 7.1 A ROS concentration-dependent phenotype. 7.1 Involvement of catalase activity and photorespiration. 7.2 Involvement of stomatal conductance. 8 The antioxidant system in lsd1 is more strained when facing stress – P.22 8.1 Glutathione disturbances 8.2 Lipid peroxidation and protein oxidation 8.3 A CAT-deficient like phenotype