“…Senescence can be induced by dark treatment, which results in starvation, but global changes in gene expression during dark treatment only show little similarity with developmental senescence . Instead, senescence triggered by a combination of low nitrogen with 2% Glc supply Pourtau et al, 2004Pourtau et al, , 2006 shows high similarity with developmental senescence (Wingler and Roitsch, 2008;Wingler et al, 2009). Sugar accumulation in old leaves signals an excess of carbon relative to nitrogen availability, and sugars can thereby integrate other environmental signals to regulate nitrogen allocation .…”