Figure 5.

Action spectra for inhibition of hypocotyl elongation in the phyB and the phyAphyB double mutants by intermittent light treatment. Photon effectiveness for the response was calculated as reciprocal of the fluence required for 20% inhibition of hypocotyl elongation based upon the data in Figure 4. The area shaded gray in the figure corresponds to the differences between the spectrum of the phyB mutant (●) and the phyAphyB double mutant (▵), and is due to the involvement of PhyA for the response.