Figure 5.

Diurnal variation in the levels of accumulation of transcript StGA20ox1 in leaves. Plants were grown in short days (SD) or short days with a night break (SD + NB) for 3 weeks. Leaf samples were harvested 30 min after the lights were turned on and taken at intervals of approximately 3 h and immediately before and after the night break. A, Light regimes used to grow the plants. The light period and night break are indicated by white bars; the dark period by a black bar. B, RNA blots hybridized with the StGA20ox1 probe. After hybridization to the StGA20ox1 probe, blots were probed with a fragment corresponding to the ribosomal S4 protein (Braun et al., 1994). StGA20ox1 mRNA levels were quantified by densitometric scanning of the film and normalized to S4 mRNA levels. The graph represents the levels of StGA20ox1 mRNA estimated for each sample compared with the highest hybridization signal (short days, 23.5 h), to which we assigned an arbitrary value of 100. Thirty micrograms of total RNA was loaded per lane. The experiment was repeated four times.