Question

Hypothetical plant hormones are
A. Florigen
B. Vernalin
C. Florigen and vernalin
D. Auxin

Answer 1

In plants there are five major forms of hormones found. These are namely- auxin, gibberellin, cytokinin, ethylene as well as abscisic acid. These hormones found in plants can work together or independently to influence plant growth. Apart from these five hormones there are hypothetical hormones present in plants which is also considered involved in some functions. For instance, vernalin is thought to be helpful in the process of vernalisation. Florigen is considered a flower inducing growth hormone.

Complete answer:
Option – A – Florigen
Florigen also known as flowering hormone is the hypothesized hormone such as molecule responsible for controlling as well as triggering flowering in plants. Florigen is produced in the leaves, and acts in the shoot apical meristem of buds or growing tips. It is considered to be graft-transmissible, as well as for performing functions between species.
Option – B – Vernalin
Vernalin is a hypothetical plant growth hormone that is formed in meristematic regions of a plant subjected to cold. Experiments concluded that apparently this substance can be transmitted to other plants by grafting and have probably failed to separate the effects of photo-period from those of vernalisation.
Option – C – Florigen and Vernalin
Both the hormone Florigen as well as Vernalin are present in Hypothesized plants and they also have essential functions to play in plant growth.
Option – D – Auxins
Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins play a role of cardinal in coordination of many growth as well as behavioural processes in plant life cycles along with it they are essential for plant body development.

So, the correct answer to this question is option C “Florigen and Vernalin”.

Note: Some scientist says that flower initiation is controlled by plant hormones known as Florigen. Whereas A German plant physiologist George Melchers has also explained the existence of vernalin. Both these hormones have not been isolated so far. So, they still remain to be a hypothetical chemical.