Question

Hormone which stimulates the initiation of the flowering process is
(a) Gibberellin
(b) Ethylene
(c) Both A and B
(d) Florigen

Answer 1

A hypothesized hormone-like molecule which is also called flowering hormone that is produced in leaves which are known to be graft-transmissible.

Complete answer:
A molecule or hypothesized hormone that helps in controlling or the initiation of the flowering process in plants is florigen. It is also called the flowering Hormone produced by leaves that acts on meristems of the shoot, buds, and glowing tips. Changes in shoot apical meristem should be done by the plant to initiate the process of flowering. when there is the correct amount of sunlight, the shoot apex receives floral stimulus(florigen) results in the initiation of flowering.

Additional Information: - Plant growth regulators(PGRs) are small, simple molecules of diverse chemical composition
- They could be indole compounds, adenine derivatives, derivatives of carotenoids, terpenes, or gases.
- Based on their functions they are divided into two groups. One group of plant growth regulators is involved in cell division, cell enlargement, tropic growth, flowering, fruiting, and seed formation which are growth-promoting activities.
- These are called plant growth promoters eg. auxins, Gibberellins, and cytokinins.
- The other group of PGRs plays an important role in plant responses to wounds and stresses inhibiting activities such as dormancy and abscission. The PGR ascorbic acid belongs to this group.
So, the correct answer is 'Florigen'

Note: Gaseous plant growth regulator, Ethylene could fit in plant growth promoter and plant growth regulator but it is mainly an inhibitor of plant growth. Auxins promote flowering, Cytokines promote nutrient mobilization, Gibberellin helps in internodal elongation and Apart from florigen, Ethylene also helps in the initiation of flowering and it also initiates germination.