Modification of the Hansatech FMS fluorometer to facilitate measurements with microalgal cultures
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770; e-ISSN 1879-1522, more
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| Keywords |
Analytical techniques > Spectroscopic techniques > Fluorescence spectroscopy
Chemical reactions > Photochemical reactions > Photosynthesis
Cultures > Algal culture
Equipment > Measuring devices
Irradiance
Dunaliella tertiolecta Butcher, 1959 [WoRMS]
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| Author keywords |
modulated fluorescence; oxygen measurement; Dunaliella tertiolecta;microalga |
| Authors | | Top |
- Rech, M.
- Mouget, J.-L.
- Tremblin, G.
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| Abstract |
This paper describes a simple modification to the Hansatech FMS1 fluorometer for fluorescence measurements in diluted microalgal cultures that increased sensitivity four-fold and allowed measurements with 0.015 mg Chl a l-1. The modified FMS1 fluorometer was used to measure the variability of fluorescence yield, calculate the electron transport rate (ETR), and plot curves for ETR versus irradiance (ETR/E) in the microalga Dunaliella tertiolecta cultured at two irradiances (75 and 350 µmol photon m-2 s-1). Curves were also plotted for oxygenic photosynthesis versus irradiance (P/E), using a Clark-type electrode. High-irradiance acclimation resulted in an increased saturation point (Ek), and maximal photosynthetic rate (Pmax). The same result was obtained in fluorescence measurements, as the maximal electron transport rate (ETRmax) increased in the same proportion as Pmax (42 and 53%, respectively). The fluorescence saturation point (ETR Ek) also increased, but in a lower proportion than oxymetric-calculated Ek (49 and 60%, respectively). The modified FMS1 fluorometer proved its reliability, allowing comparison of photosynthesis estimated either by oxygen evolution or fluorescence measurements. The relation between the two methods was not always linear, illustrating the strong effects of the cuvette geometry in fluorescence measurements, and the difficulty of converting fluorescence data into oxygen evolution rates. |
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