TITLE: Measuring Photophysiology of Attached Stages of Colacium sp. by a Cuvette-Type Fast Repetition Rate Fluorometer
AUTHORS: Takehiro Kazama, Kazuhide Hayakawa, Koichi Shimotori, Akio Imai

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block"><span>Fast repetition rate fluorometer (FRRf) is a beneficial method for measuring photosystem II (PSII) photophysiology and primary productivity. Although FRRf can measure PSII absorption cross section (</span><span style = "font-style:italic;font-style:italic;">σ</span><span style = "font-style:italic;font-style:italic;">PSII</span><span>), maximum photochemical efficiency (</span><span style = "font-style:italic;font-style:italic;">F</span><span style = "font-style:italic;font-style:italic;">v</span><span style = "font-style:italic;">/F</span><span style = "font-style:italic;font-style:italic;">m</span><span>), effective photochemical efficiency (</span><span style = "font-style:italic;vertical-align:sub;">F</span><span style = "font-style:italic;vertical-align:sub;">q</span><span style = "vertical-align:sub;">′/F</span><span style = "font-style:italic;vertical-align:sub;">m</span><span style = "font-style:italic;vertical-align:sub;">′</span><span>), and non-photochemical quenching (</span><span style = "vertical-align:sub;">NPQ</span><span style = "font-style:italic;vertical-align:sub;">NSV</span><span>) for various eukaryotic algae and cyanobacteria, almost all FRRf studies to date have focused on phytoplankton. Here, we describe how to measure PSII photophysiology of an epizoic alga </span><span style = "vertical-align:sub;">Colacium </span><span>sp.Ehrenberg 1834 (Euglenophyta), in its attached stage (attached to zooplankton) using cuvette-type FRRf. First, we estimated the effects of substrate zooplankton (</span><span style = "vertical-align:sub;">Scapholeberis mucronata</span><span> O.F. Müller 1776, Cladocera, Daphniidae) on background fluorescence and </span><span style = "font-style:italic;vertical-align:sub;">σ</span><span style = "font-style:italic;vertical-align:sub;">PSII</span><span style = "font-style:italic;vertical-align:sub;vertical-align:sub;">,</span><span style = "vertical-align:sub;"> F</span><span style = "font-style:italic;vertical-align:sub;">v</span><span style = "vertical-align:sub;">/F</span><span style = "font-style:italic;vertical-align:sub;">m</span><span>, </span><span style = "font-style:italic;vertical-align:sub;">F</span><span style = "font-style:italic;vertical-align:sub;">q</span><span style = "vertical-align:sub;">′/F</span><span style = "font-style:italic;vertical-align:sub;">m</span><span style = "font-style:italic;vertical-align:sub;">′</span><span>, and </span><span style = "vertical-align:sub;">NPQ</span><span style = "vertical-align:sub;vertical-align:sub;">NSV</span><span> of planktonic </span><span style = "vertical-align:sub;">Colacium </span><span>sp. To validate our methodology, we recorded photophysiology measurements of attached </span><span style = "vertical-align:sub;">Colacium </span><span>sp. on </span><span style = "vertical-align:sub;">S. mucronata</span><span> and compared these results with its planktonic stage. Representative results showed how the protocol can determine effects of Ca and Mn on </span><span style = "font-style:italic;">Colacium</span><span> sp. photophysiology and identify the various effects of Mn enrichment between attached and planktonic stages. Finally, we discuss the adaptability of this protocol to other periphytic algae.</span></div></div>

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