Read the Signals that Time Flowering
Flowering begins only after developmental competence and the right seasonal signals align.
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Switch from vegetative to reproductive growth
Plants commonly accumulate resources during vegetative growth before flowering. The transition depends on age, genotype, hormones and environmental cues.
Read day length and cold
Leaves perceive photoperiod and signal the shoot apex. Short-day plants flower when day length is below their critical value; long-day plants when it exceeds theirs. Species have different critical photoperiods, so a short-day and a long-day plant can flower together under an intermediate day length. Vernalization is promotion of flowering by cold treatment.
Read red and far-red night interruptions
A short-day plant needs an uninterrupted long night. Red-light exposure converts Pr to Pfr and can interrupt that night, whereas far-red reverses Pfr to Pr. If the only accidental flash is far-red, it does not create the inhibitory red-light state, so the normal short-day treatment can continue without correction. Choose D.
OlympIQ exam lens
- ✓Leaves perceive photoperiod.
- ✓Short-day: day below critical length; long-day: above it.
- ✓Vernalization: cold-induced flowering competence.
- ✓Far-red reverses the Pfr state generated by red light and can cancel a red-light night interruption.
Photoperiod is the duration of light, not simply light intensity.
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