Changes in proteins were measured to test whether they were linked to flowering, the cell cycle or both inSilene coeli-rosashoot apices. Seeds were germinated and grown at 20°C in short days (SD) of 8 h light from fluorescent and tungsten (F+T)/16h darkness for 28 days (day 0). Plants were then exposed to: 7 long days (LD)+2 SD (inductive), 7 LD+48 h darkness (inductive) or 7 dark-interrupted (di) LD+2SD (non-inductive), where each LD and diLD comprised 8 h F+T/16 h T, 8 h F+T/l h darkness/15 h T, respectively. There were no qualitative differences in polypeptide composition in the LD and SD treatments on days 0, 5, 6 and 7 but 60 new polypeptides were detected on LD8and some modifications in the intensity of common spots also occurred. These qualitative and quantitative changes were not altered following 7 LD+48 h darkness, which is known to suppress synchronisation of the cell cycle but not flowering. Thus, changes on day 8 are linked to flowering. Transient increases in protein per unit area were detected in prophase cells on days 0, 3, 4 while sustained increases occurred on days 7 and 8. The changes on days O, 3 and 4 were suppressed by the diLD treatment. Thus, quantitative changes to proteins, co-inciding with known LD-induced changes to the cell cycle, are linked to flowering
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