Fig. 1.

A rapid LD flowering response of Arabidopsis, ecotype Columbia. Effect of a single LD on flowering of plants of Columbia (% plants flowering; A). The four daylength treatments imposed here and in further studies are shown schematically in (B). Prior to the single LD exposure, all plants were grown in 8 h SD for 5 weeks. After the LD, they were returned to SDs for daily recording of flowering. At 40 d (75 d from germination) there was little or no flowering of plants in SDs or after a single low intensity R-rich LD. There were 16 replicate plants for flowering assays. The shaded areas show the ‘overnight’ 16 h light or dark exposure.