Fig. 1
A schematic drawing of the development of the model plant Arabidopsis thaliana is shown at the top. At the transition from growth to reproduction (dotted grey line), senescence switches from sequential senescence which remobilizes nutrients from old to young leaves to monocarpic senescence in plants which started to bolt and flower. Now nutrients are remobilized from all rosette leaves to the now developing reproductive organs. During the time interval of bolting and flowering, intracellular hydrogen peroxide contents were measured and are indicated in arbitrary units of DCFDA fluorescence. H2O2 levels increased during transition to reproductive growth and the long-term increase at the transition point is indicated by the orange bar. H2O2 concentration showed more pronounced elevations in young (dark red; pos. 8–12 within the rosette) and middle-aged leaves (red, pos.4–7 within the rosette) than in old leaves (orange, pos. 1–3 within the rosette). The age of the plants is indicated in weeks after sowing (w)