Figure 2.

Time course analyses of water uptake and oil mobilization during wild-type tobacco seed germination. A, The incidence of testa rupture (⋄, ♦) and endosperm rupture (○, •) expressed as percent of approximately 100 seeds scored with time after the start of imbibition in medium without (Control, white symbols) and with (ABA, black symbols) 10 μm ABA. The gray boxes and their numbers correspond to the sections of Figures 3 and 4 showing in vivo NMR microimaging of seeds from these time windows. B, Water uptake measured gravimetrically (○, •; micrograms water per seed) and by in vivo ¹H-MAS NMR (▵, ▴; relative values per seed); Control (white symbols), ABA (black symbols). I, II, and III are the three phases of water uptake as described in the text. C, Seed oil mobilization measured biochemically as triacylglycerides (TAG, ○, •; micrograms per seed) and by in vivo ¹³C-MAS NMR (linoleic acid, ▵, ▴; oleic acid, ⋄, ♦; relative contents per seed); Control (white symbols), ABA (black symbols). Mean ± se of at least three samples are presented for each time point. When error bars are not shown, the ±se values are <2 (A) or <1 (B and C).