Which of the following processes is called springization or springification?

Florigen is synthesized in

Give scientific reasons:
$(1)$ Photoperiodism is essential for flowering in plants.
$(2)$ Abscission (leaf fall,flower fall,fruit fall) increases the vitality of plants.

It is known that some varieties of wheat are sown in autumn but are harvested around next mid-summer.
$(A)$ What could be the probable reason for this?
$(B)$ What term is used for this promotion of flowering under low temperature?
$(C)$ Which plant hormone can replace the cold treatment?

When flowering is regulated by the length of day and night,it is called

Phytochrome is closely related to