Phytochrome plays an important role in

$A$ group of plants flowered when exposed to a $12$ hour day and $12$ hour night cycle. Another group of the same plants did not flower when exposed to the same day-night cycle but with a brief light interruption during the night. What type of plants are these?

Florigen is produced in the region of

When the dark period of short-day plants is interrupted by a brief exposure of light,then the plant:

Define/Explain: Short-day plants.

In respect of photomorphogenesis,plants are most sensitive to: