Simple determination of photosynthetic efficiency and photoinhibition of Dunalielia tertiolecta by saturating P" 3e fluorescence measurements

Abstract

Saturating pulse fluorescence measurements, well known from studies of higher plants, were applled to cultures of the chlorophyte Dunallella tertiolecta Photochemical and non-photochemlcal quenching, and the photochemlcal yield and photochemical efficiency of photosystem 11, were deternuned for cultures of D tertiolecta growing under varying light intensit~es Photosynthetic efflciencies appeared to correlate well with growth rates determined for the D tertlolecta cultures The photochemlcal yield provides a measure of photoinhibition effects The results indicate that the saturating pulse fluorescence method may be successfully used to d e t e r m n e photosynthetic charactensbcs of phytoplankton The technique is simple to apply and can be adapted for photosynthetic measurements in situ i e on phytoplankton in thelr natural habitat