Assertion : Photomodulation of flowering is a phytochrome - regulated process. Reason : Active form of phytochrome (Pfr) directly induces floral induction in shoot buds.

Step-by-step solution

Flowering is a phytochrome regulated process. Phytotchrome is a blue protein pigment with a molecular mass of about 125 k Da (kilodaltons). Phytochrome occurs in two interconvertible form P_R (which absorbs red light) and P _ fr (which absorbs far red light). The studies with mutants of Arabidopsis support and prove that the P _ fr is the active form of phytochrome. When P _ R molecules are exposed to red light, most of them absorb it and converted to P _ fr . This causes floral induction in the shoot.