自然光下の測定によるウミショウブの光合成光化学効率の日変化

抄録

The diurnal change in photochemical efficiency of a seagrass, Enhalus acoroides was determined in Okinawa, Japan. The measurements under incident sunlight were conducted from sunrise through sunset using a submersible pulse amplitude modulation (PAM)-chlorophyll fluorometer (Diving-PAM). The effective quantum yield (ΔF/F_m’) declined with increasing incident sunlight in the morning, with a ΔF/F_m’ minima occurring during noon-time. Thereafter, the ΔF/F_m’ gradually recovered during the afternoon incident sunlight decreased, indicating a dynamic negative response to the excess sunlight. The decline of ΔF/F_m’ in the habitat is likely a photoprotective response to protect the photosynthetic reaction center from damage by excess light energy.