Abstract
The quantum yield of electron transport at photosystem2 (PS2), Φ2, can be easily estimated by measurement of chlorophyll fluorescence. On the other hand, certain fractions of light absorbed by PS2 is not used for photosynthetic electron transport (1-Φ2) and spent as energy-wasting processes. These processes are divided into non-photochemical dissipation which relates to chlorophyll fluorescence parameter NPQ and non-photochemical basal dissipation. Whereas energy allocation in PS2 would be important factor for plant production, most characterization are done with plants grown in growth chambers, and not with field grown plants. In this report, we measured diurnal changes of chlorophyll fluorescence with field-grown rice (Nipponbare) and estimated the allocation of absorbed light energy in PS2 based on the model of Hendrickson et al. (2004). At the same time the degree of photoinhibition was also determined. We discuss the factors that restrict the quantum yield of the electron transport at PS2in the field-grown rice.
