The spectral composition of sunlight in natural aquatic habitats depends on the depth of submer gence and the solar time. Changes in the fractional amount of far red light (FRL) in the total photon flux are associated with the redistribution of light energy absorbed by the two photosystems of photosynthesis. Exper iments with a culture of Scenedesmus quadricauda revealed the influence of FRL preillumination on photo synthetic electron transport and associated processes in microalgae. The plant efficiency analyzer M PEA 2 was used to measure simultaneously the induction curves of prompt fluorescence, delayed fluorescence, and the redox transients of chlorophyll P700. The results are discussed in terms of the action of FRL preillumi nation on cyclic and noncyclic electron flows with account for relocation of the mobile light harvesting com plex of photosystem II during reversible State 1-State 2 transitions. Essential similarities and substantial dis tinctions have been revealed in the effects of FRL on photosynthetic electron flows in microalgae and higher plant leaves.Abbreviations: DF-delayed chlorophyll fluorescence; FNRferredoxin NADP reductase; FRL-far red light; P700-the pigment of photosystem I reaction center; PF-prompt fluores cence; PQ-plastoquinone; PSI and PSII-photosystems I and II; Q A and Q B -the primary and secondary quinones serving as elec tron acceptors in PSII.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.