An efficient excitation energy transfer from a carotenoid, siphonaxanthin to chlorophyll a observed in a deep-water species of chlorophycean seaweed

Excitation spectra of chlorophyll a fluorescence and absorptionspectra of the thalli of Ulva japonica and Ulva pertusa werestudied at room temperature. Both the fluorescence excitationspectrum and absorption spectrum of the former showed a characteristicbroad peak at 540 nm, which those of the latter lacked. It wasinferred that siphonaxanthin in the former efficiently transferredits excitation energy to chlorophyll a. ¹ Contributions from the Shimoda Marine Research Center, No.312. (Received August 30, 1976; )