Nicotiana tabacum, a Short Day Plant, when exposed to more than critical period of light fails to flower. Explain.

Short day plants such as Nicotiana tabacum require a photoperiod (the amount of day and night) of less than 12 hours in order to flower. If the day was to extend beyond the critical period of light (typically around 12 hours for Nicotiana tabacum) then the plant may fail to flower due to its requirement of the short-day photoperiods. This can happen due to changes in seasons or times of the day and occurs when the photoperiod may be too long for the plant to trigger flowering.