Fig. 3.

Spatial transcript accumulation patterns of CONSTANS (CO) and FLOWERING LOCUS T (FT) are not altered in response to day: night temperature fluctuations in Arabidopsis thaliana (Columbia-0 (Col-0)). Nighttime induction of CO in response to cool nighttime temperatures occurs regardless of day length; FT induction by cool temperatures does not occur in short day (SD). (a–d) Tissue specific patterns of GUS activity in pCO:GUS (a, b) and pFT:GUS (c, d) plants grown in LD22/22°C (long days with day: night temperatures = 22°C: 22°C) and LD22/12°C conditions for 5 d. Scale bars, 1 mm. (e, f) CO transcript accumulation and (g, h) FT transcript accumulation on day 4 in SD or 12-h, mid-length-day (MD) treatments with 22°C daytime temperatures and 22°C or 12°C nighttime temperatures. Replicate of FT transcript accumulation in LD22/22°C conditions is included for comparison. Data represent means ± SEM derived from at least three biological replicates. (e–h) Asterisks (*) indicate P<0.05 and 95% CI of difference between pair did not contain zero. ZT, zeitgeber time.