The pigment phytochrome is involved in:

Vernalization stimulates flowering in

The term "photoperiodism" was proposed by, or the phenomenon of photoperiodism in plants was discovered by:

One set of a plant was grown at $12$ hours day and $12$ hours night period cycles and it flowered,while in the other set,the night phase was interrupted by a flash of light and it did not produce flowers. Under which one of the following categories will you place this plant?

Phytochrome occurs in two forms. In which form does it promote the germination of seeds of some species?

$A$ pigment concerned with both floral induction and seed germination is