[2pt] 12. The figure shows a short-day condition (long night) and the effect of a
night interruption with a brief red light pulse (R), followed by far-red light (FR) (row
3). Which option BEST predicts flowering outcomes for the long-day plant and
short-day plant in row 3?
ALL PURPOSE
TERTRIZ
16-16-16
Hours Long-day plant Short-day lant
6 18 24
Short day Long night
-Light flash
(
(A) Long-day plant does not flower; short-day plant flowers because FR pulse
reverses the effect of the R pulse.
(
(B) Short-day plant flowers in row 3 because the day length is still short, and shortday plants require short days to flower. Critical night length
(
(C) Long-day plant flowers; short-day plant does not flower because the red light night-break shortens the effective night length.
(
(D) Long-day plant does not flower; short-day plant flowers because the day length remains short.
(
(E) Long-day plant flowers; short-day plant flowers because both receive some light during the night