Participation of ascorbic acid coordinating chloroplast and mitocondria metabolisms

CARLOS G. BARTOLI; MARÍA E. SENN; GUSTAVO GERGOFF GROZEFF

Mar del Plata

Congreso; XV Congreso Latinoamericano de Fisiología Vegetal- XXX Reunión Argentina de Fisiología Vegetal.; 2014

Sociedad Argentina de Fisiología Vegetal

Ascorbic acid (AA) is synthesized in mitochondria but it participates in several processes in different compartments of plant cells. One major function of this antioxidant consists of its crucial role on photoprotection. In turn, photosynthesis stimulates AA synthesis through the oxidation of its precursor L-Galactono-1,4-lactone (L-GalL) by the mitochondria electron transfer chain. The experiments of this work were designed to demonstrate the participation of changes on AA contents linking the metabolisms of mitochondria and chloroplasts. The experiments were performed with wild and mutant Arabidopsis plants (vtc2, Nottingham Arabidopsis Stock Centre) containing low levels of AA (around 10 % of wild plants). The leaves were exogenously supplemented with L-GalL getting higher, similar or lower AA levels than wild plants. Former experiments show that the level of AA correlates with the photosynthetic activity measured as either CO2 uptake or electron transport rate, especially in vtc2 plants. In addition, vtc2 plants with increased AA content showed higher stomatal conductance. Respiration was higher in vtc2 plants but was not modified by the application of L-GalL. We are currently studying the physiological basis of the photosynthesis stimulation induced by AA levels.