Question

Maryland mammoth tobacco is a short-day plant. Its critical duration of darkness is 10 hours. Under which of the following conditions will it not flower?

(A)

(B)

(C)

(D)

Answer 1

Hint: Photoperiodism of the plant refers to the reactivity of the plant to the length of light and darkness received by it. Based on this plant can be divided into long-day plants, short-day plants, and day-neutral plants. The amount of sunlight received by them differs.

Complete answer: Short-day plants are those which are in requirement of longer darker periods and very short light periods. The darkness makes them flower. If their dark period is interrupted or gets shortened due to some reason then they don’t flower. The nighttime darkness is not enough for such plants. So, they need to be kept in a place where darkness can be maintained for a long stretch of the time period. Even the presence of a small amount of light can interrupt their flowering period.
Additional information: Long day plants are those plants which need sunlight or source of light for the maximum duration of the day. They need less dark periods. They flower when the days get longer and nights to become shorter. Interruption in their photoperiod can stop their flowering. Day-neutral plants are those plants that don’t depend on the presence or absence of light for their flowering. They are independent of their photoperiod. They initiate their flowering time when they have suitable climatic conditions.

So, the correct answer is ‘d’.

Note: The photoperiodism plays an important role in the flowering of the plants. Interruption in their dark or the light period can lead to the non-flowering of the plants. So extra care is required by such plants so that they can flower properly on time. The day-neutral plants do not require such care as they can flower without being dependent on the photoperiod.