Biochemical assays
Leaf samples were harvested at the time points indicated, immediately
frozen in liquid nitrogen, and stored at -80°C until further analysis.
Extraction was performed by rapid grinding of tissue in liquid nitrogen
and the immediate addition of ethanol as described in Gibon et al.
(2004). Photosynthetic pigments
were determined as in Porra et al. (1989). The levels of starch,
sucrose, glucose, and fructose were determined exactly as described
previously (Fernie et al., 2001). Malate and fumarate contents were
determined as described before (Nunes-Nesi et al., 2007). Protein and
amino acid contents were determined as described previously (Cross et
al., 2006).