Fig. 5
Changes over time in chlorophyll fluorescence parameters for control and drought stressed maize plants. a F, fluorescence yield; b Y(NO), quantum yield of nonregulated energy dissipation; c Fm’, maximum fluorescence yield on light-adapted leaf; d Y(II), effective PSII quantum yield; e qN, coefficient of non-photochemical quenching (lake model); f Y(NPQ), quantum yield of regulated energy dissipation; g NPQ, non-photochemical quenching; h qP, coefficient of photochemical quenching (puddle model); i qL, coefficient of photochemical quenching (lake model); j PS/50, apparent rate of photosynthesis. Data were obtained at 280 µmol m−2 s−1 of actinic lighting. The values of the parameters every 2 days represent the average of 20 replicates considering all studied maize genotypes. Both groups of plants (control and drought) were with soil water content at field capacity at the start of measurement (±60 days after sowing; 1st day). From there, the watering was withheld in the drought stressed plants until the substrate reached the theoretical wilting point (−1.5 MPa) on the 7th day. Bars represent standard error of the mean