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6.6 Transition to Flowering — Test 1
Q1. The light signals that control flowering are perceived by the:✓ Leaves
Q2. The mobile signal (florigen) that moves from the leaves to the shoot apex to induce flowering is:✓ FLOWERING LOCUS T (FT) protein
Q3. At the shoot apex, FT promotes flowering by partnering with which transcription factor?✓ FD (FLOWERING LOCUS D)
Q4. In long-day plants, the protein CONSTANS (CO) promotes flowering by:✓ Activating FT transcription in the leaves under long days
Q5. The flowering-repressor gene responsible for the vernalization requirement in Arabidopsis is:✓ FLOWERING LOCUS C (FLC)
Q6. Vernalization promotes flowering by:✓ Epigenetically silencing the floral repressor FLC after prolonged cold
Q7. FRIGIDA (FRI) in Arabidopsis acts during floral induction as:✓ An activator of the floral repressor FLC (delaying flowering)
Q8. Two major classes of genes regulating floral development are:✓ Meristem-identity genes and floral organ-identity genes
Q9. LEAFY (LFY) in Arabidopsis functions in:✓ Establishing floral meristem identity
Q10. APETALA1 (AP1) acts as a floral meristem-identity gene; ectopic AP1 in an embryonic-flower (emf) mutant shows that AP1:✓ Promotes flowering
Q11. The shoot apical meristem, on receiving the floral signal, converts from an indeterminate shoot meristem into a:✓ Determinate floral meristem
Q12. Floral meristems are usually distinguished from vegetative meristems by their:✓ Larger size, from an increased rate of central-cell division
Q13. The integration of multiple flowering signals (photoperiod, vernalization, age, GA) occurs at integrator genes such as:✓ SOC1 and FT
Q14. Gibberellin (GA) promotes flowering, especially under non-inductive (short-day) conditions, by:✓ Activating floral integrator and identity genes (e.g. LFY, SOC1)
Q15. The juvenile-to-adult transition primes a plant to flower; it involves a fall in:✓ miR156 (allowing SPL genes to rise)
Q16. Short-day plants flower when the night length:✓ Exceeds a critical length
Q17. The pigment that allows plants to measure day/night length for flowering is:✓ Phytochrome
Q18. The circadian clock contributes to photoperiodic flowering by:✓ Timing CO expression so FT is induced only under the right day length
Q19. Overall, the transition to flowering is best described as:✓ The integration of internal and environmental signals to switch the meristem to a floral fate
Q20. Once flowering is induced, the floral meristem-identity genes (LFY, AP1) then activate the:✓ ABC floral organ-identity genes