Assertion: Vernalization is acceleration of subsequent flowering by low temperature treatment. 
Reason: Site of vernalization is apical meristem.

Options

A. If both assertion and reason are true reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

B

Explanation

Both assertion and reason are true but reason is not the correct explanation of assertion.
Term vernalization was first given by T.D. Lysenko (1928). In order countries, there are cereals of 2 pphysiological types, i.e, winter cereals and spring cereals. Winter cereals are sown in winter and flower in following summer whereas spring cereals are sown in spring and flower in summer. If winter cereal is sown in spring and flower in summer. If winter cereal is sown in spring. It shows vegetative growth but does not flower unless it receives low temperature of winter. But winter cereal an be converted into spring cereal by providing artificial low temperature treatment, (i.e, springification.) Some plants requiring low temperature requirement (vernalization) for flowering are secale cereale (European rye), Triticum vulgare, Brassica oleracea, Beta vulgaris, Apium and Lollium perenne, etc. Site of vernalization is apical meristem or all the meristematic cells. As a result of vernalization, a flowering hormone called "vernalin" is formed (reported by Melchers), but venalin has never been isolated.Once a plant is vernalized ,It can be devernalized by exposing the plant to temperature of `30^(@)C` or above. For establishing vernalization, plant should be kept at `20^(@) C` for `4-5` days.