Assertion : In some plants flowering depends only on a combination of light and dark exposure.
Reason : The site of perception of light or dark duration are the shoot apices of plants.

Options

A. If both assertion and reason are true and 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

d

Explanation

Some plants require a periodic exposure to light to induce flowering. It is now also known that not only the duration of light period but the duration of dark period is also of equal importance. Hence, it can be said that flowering in certain plants depends not only on a combination of light and dark exposures but also their relative durations. This response of plants to periods of day/night is termed photoperiodism. The shoot apices modif themselves into flowering apices prior to flowering, shoot apices cannot perceive photoperiods by themselves. The site of perception of light/dark duration are the leaves.