Figure 2.

Pn FT1 and Pn FT2 Transcript Abundance Correlates with the Flowering Behavior of Pharbitis cv Violet.

(A) Pn FT1 and Pn FT2 expression under LD and SD. Expression levels were quantified from DNA gel blots shown below and normalized to Ubiquitin expression. Plants were grown under LDs (16 h light/8 h dark) or SDs (10 h light/14 h dark) for 4 d, and cotyledons were harvested every 4 h in the last day–night cycle.

(B) and (C) The effect of night break on Pn FT1 and Pn FT2 mRNA levels in Pharbitis. Real-time PCR was performed to quantify Pn FT1 and Pn FT2 mRNA. All seedlings were grown under continuous light and then transferred to continuous darkness on day 5. One population of plants received 10 min of white light (a night break) 8 h after transfer to dark, whereas the control population did not receive the light treatment. Cotyledons from both populations were harvested every 2 h from 6 to 30 h in dark. Plants exposed to a night break (NB; solid line) or control plants (cont; dotted line). Error bars show se of three PCR experiments. A biological replicate provided a similar result.

(D) Flowering time of control plants and plants exposed to night break (NB). Plants were first grown under the same conditions as used in (B) and (C), and after 48 h in continuous darkness, they were transferred to continuous light. Flowering was measured 4 weeks after the start of the experiment as the total number of flower buds present on each of eight plants in both groups.