The time when a night break is given determines
the flowering response. When given during a long
dark period, a night break promotes flowering in LDPs and
inhibits flowering in SDPs. In both cases, the greatest effect
on flowering occurs when the night break is given near the
middle of the 16-hour dark period. The LDP Fuchsia was given a 1-hour exposure to red light in a 16-hour dark
period. Xanthium was exposed to red light for 1 minute in a
16-hour dark period. (Data for Fuchsia from Vince-Prue
1975; data for Xanthium from Salisbury 1963 and Papenfuss
and Salisbury 1967.)