Figure 5.

Influence of seed pod excision or prolonged dark treatment of intact plants on p107 phosphorylation in stage VII developing COS. Stems containing intact pods of developing COS were excised and placed in water in the dark at 24°C. Alternately, intact plants cultivated under a 16-h-light/8-h-dark regime in a growth chamber as described in “Materials and Methods” were subjected to darkness for 72 h and then illuminated for an additional 8 h (72 D → 8 L). At the indicated times, endosperm tissue from stage VII COS was harvested, extracted, and subjected to SDS-PAGE (A) or nondenaturing PAGE (B) and immunoblotting with anti-(B. napus PEPC)-IgG or APS-IgG (40 μg protein/lane). In-gel PEPC activity staining was also performed following nondenaturing-PAGE (B).