c Fluorescence induction curves at 3,500 μmol photons m−2 s−1 of continuous red light for 1 s recorded after 30-min recovery in the dark. (open circle sun leaf (100 % of daylight), filled circle shade leaf (13 % of daylight)). Mean values ± SE from 4 replicates Table 4 Selected parameters derived from fast fluorescence kinetic measurements in the sun PD0332991 purchase and the shade barley leaves before (B) and after they were exposed to high light (HL) Sun Shade B HL B HL F 0 535 ± 8a 564 ± 4b 573 ± 21b 618 ± 9c F m 3,233 ± 29a 2,710 ± 42b 3,294 ± 93a 2,416 ± 69c F V/F m 0.84 ± 0.001a 0.79 ± 0.003b 0.83 ± 0.007a 0.74 ± 0.009c S m 31.2 ± 2.9a 28.5 ± 1.2a 19.6 ± 0.8b 21.2 ± 1.6b ψET2o
0.63 ± 0.01a 0.57 ± 0.01ab 0.55 ± 0.01ab 0.53 ± 0.01b ψRE1o 0.26 ± 0.01a 0.28 ± 0.01a 0.16 ± 0.003c 0.21 ± 0.01b ABS/RC 2.22 ± 0.06a 2.30 ± 0.03a 2.58 ± 0.22ab 2.80 ± 0.13b p 2G 0.27 ± 0.05a 0.26 ± 0.04a 0.12 ± 0.03b
0.18 ± 0.02ab p 0.51 ± 0.04a 0.45 ± 0.04a 0.28 ± 0.07b 0.29 ± 0.02b ω 0.64 ± 0.05a 0.59 ± 0.05a 0.36 ± 0.09b 0.43 ± 0.03b More detailed description and calculations are given in Tables 1 and 2 and their legends. Values represent the mean ± SE (n = 4). Letters indicate significant differences at P < 0.05 according to Duncan’s multiple range tests Sun—full light; shade—light level ~13 % of full light. B—measurements before high light protocol; HL—measurements after high light protocol and dark adaptation (HL). Parameters: F 0—minimum fluorescence in dark-adapted Tariquidar clinical trial leaves; F m—maximum fluorescence in dark-adapted leaves; F V/F m—related to maximum photochemical efficiency of PSII; S m—normalized area; ψET2o—probability with which trapped electron is passed beyond QA; ψRE1o—probability with which trapped electron is passed beyond PS I; p 2G—overall grouping probability of PSII units;
p—connectivity parameter; ω—probability of connectivity among PSII units The first part of fast ChlF kinetics Isotretinoin (from 0.05 to 2 ms) measured at high frequency (up to 100 kHz) was used to estimate the connectivity parameter among PSII units (Joliot and Joliot 1964; Strasser and Stirbet 2001; Joliot and Joliot 2003; Stirbet 2013). Calculated values of parameters associated with connectivity, the curvature parameter—C and probability of connectivity among PSII units—p (as defined by Strasser and Stirbet 2001), were ~2 times higher in sun leaves compared to those in the shade (Table 4). This connectivity reflects the fact that the light-harvesting antenna is not associated with only one separated RC, as assumed in many models, including the JIP test (cf. Stirbet and Govindjee 2011), but that the RCs are partially connected (Butler 1978; Lavergne and Trissl 1995; PF-573228 ic50 Kramer et al. 2004), meaning that the excitation energy of closed RCs can be transferred to a number of nearby open RCs.