Paramecium bursaria

Paramecium bursaria culture techniques

Green Paramecium bursaria strains were grown on a lettuce medium with Klebsiella pneumoniae (SMC strain) ( Sonneborn, 1970). ffle cultures were maintained under constant light/dark cycle (12L:12D) at 18°C, at light intensity 200 µmol m-2 s-1 for 7 days at the following temperatures: 21°C, 24°C, 27°C, 30°C and 33°C.

Chlorophyll a uorescence

Chlorophyll a uorescence was measured using a Handy Plant E ciency Analyser

uorimeter (Hansatech Instruments, United Kingdom). A 1 ml sample, with green P. bursaria , was taken into glass cell, then the sample was darkened for 5 minutes to make the conditions needed to expire the light phase of photosynthesis. ffle ob-

tained results were analysed as follows: F

0

– chlorophyll uorescence intensity meas-

ured when all photosystem II reaction centres are open, F

m

– maximal chlorophyll

uorescence intensity measured when all photosystem II reaction centres are closed,

F v – variable chlorophyll uorescence (F m /F 0), F v /F 0 – e ciency of the water-splitting complex on the donor side of PSII and F v /F m – maximum quantum yield of PSII. In addition, T

fm

– time needed for reaching F

m

(ms), RC/ABS – index expression as the

density of reaction centres (RC), PI – indicator of the functioning of PSII, TRo/RC –

trapped energy ux per cross section (RC) at t = 0, ETo/RC – electron transport ux

per cross section (RC) at t = 0, and Vj – relative change in chlorophyll uorescence

during the light phase of photosynthesis.

Emission uorescence – spectro uorimetry method

Measurement of blue-green and red uorescence emission spectra were performed according to Lichtenthaler et al. (2004) with a spectro uorimeter (Perkin-Elmer LS55B, United Kingdom) equipped with a liquid measuring device. Measurements of

uorescence intensity in the range of blue-green light (430–650 nm) were performed at 390 nm and near and far red (650–800 nm) with blue 430 nm. ffle slot for the excitation radius was 15 nm, and for the emitted 20 nm. Results were analysed using FL WinLab version No. 3.00.

Statistic analysis

A parametric multi-factorial ANOVA / MANOVA test was used to compare the variables tested, based on multiple Duncan homogeneous tests at p ≤ 0.05; n = 5. Calculations were made using StatSo, Inc. (2014). STATISTICA ° 12. Program.