What helps in flowering?

Step-by-step solution

Phytochrome is an amorphous photoreceptor protein pigment. It exists in two states, i.e ., phytochrome Red ( P r ) and phytochrome far-red P f r . It is considered that during the day, P f r from of the phytochrome is accumulated in the plant which is inhibitory to flowering in short-day plants, but is stimulatory in long day plants.