Fp 100

A total of 105 chlorophyll fluorescence measurements were taken: 15 repetitions each (five leaves of three individuals) every five days for 30 days from the day watering stopped. Measurements were taken between 13:00 to 14:00. For the first 10 days of drought stress treatment, the 13th to 15th leaves from the growing point were measured. After the 15th day of treatment, the 7th to 10th leaves from the growing point were measured. The same leaves were used for both the photosynthesis measurements and the chlorophyll fluorescence measurements. The leaf clip was bitten on the plant leaf before measurement and irradiated after 20 min of dark treatment. F_v/F_m, ΦPSII,, RFd, and NPQ were measured using a quenching kinetics analysis after 20 min of dark treatment in a chlorophyll fluorescence analyzer chamber using a Handy Cam (FlorCam, CZ; Barbagallo et al., 2003 (link); Genty et al., 1990 (link)). Continuous, actinic light (red LED) was used at a moderate light amount of 200 µmol m⁻² s⁻¹ and a saturating light amount of 1,250 µmol m⁻² s⁻¹ to induce chlorophyll fluorescence for the measurements. The measured data were analyzed using the methods presented by Gorbe & Calatayud (2012) (link). PI_ABS was calculated using a chlorophyll fluorescence meter (FP-100, Photon System Instruments, Czech Republic) according to the JIP-TEST method (Stirbet & Govindjee, 2011; Table 1).