Photosynthesis was assessed by measuring the chlorophyll a fluorescence using a portable fluorometer (FluorPen FP100 PAM, Photo System Instruments, Czech Republic). After dark adaptation (for at least 30 min), the minimum fluorescence was measured by applying a weak-intensity modulated light and the maximum fluorescence in the dark was measured after using a saturating pulse of light. Then, leaves were adapted to light conditions. The steady-state fluorescence was established, and the maximum fluorescence in light was assessed after a saturating light pulse. The maximum quantum efficiency of photosystem II (Fv/Fm), the effective quantum efficiency of PSII (ΦPSII), the photochemical quenching (qP) and non-photochemical quenching (NPQ) were calculated according to van Kooten and Snel (1990) (link).
Chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids and anthocyanins were quantified as described by Sims and Gamon (2002) (link). For the photosynthetic pigments’ extraction, leaf discs were homogenized with an acetone:50 mM Tris (80:20) buffer, and for the anthocyanins’ extraction, leaf discs were homogenized with a methanol/HCL/H2O (90:1:1) solution. After centrifugation (5 000 g for 5 min at 4°C), the absorbance of the acetone extracts was read at 470, 537, 647 and 663 nm and the methanolic extracts were read at 529 and 650 nm using a Jenway 7305 spectrophotometer. The contents of pigments were calculated according to Sims and Gamon (2002) (link).
Chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids and anthocyanins were quantified as described by Sims and Gamon (2002) (link). For the photosynthetic pigments’ extraction, leaf discs were homogenized with an acetone:50 mM Tris (80:20) buffer, and for the anthocyanins’ extraction, leaf discs were homogenized with a methanol/HCL/H2O (90:1:1) solution. After centrifugation (5 000 g for 5 min at 4°C), the absorbance of the acetone extracts was read at 470, 537, 647 and 663 nm and the methanolic extracts were read at 529 and 650 nm using a Jenway 7305 spectrophotometer. The contents of pigments were calculated according to Sims and Gamon (2002) (link).
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