An efficient excitation energy transfer from a carotenoid, siphonaxanthin to chlorophyll a observed in a deep-water species of chlorophycean seaweed1

Excitation spectra of chlorophyll a fluorescence and absorption spectra of the thalli of Ulva japonica and Ulva pertusa were studied at room temperature. Both the fluorescence excitation spectrum and absorption spectrum of the former showed a characteristic broad peak at 540 nm, which those of the latter lacked. It was inferred that siphonaxanthin in the former efficiently transferred its excitation energy to chlorophyll a.