Fig. 3

Maximum quantum efficiency of PSII primary photochemistry and effective quantum yield of PS II. Fv/Fm (a) and ΦPSII (b) were measured in the 3rd leaf of plants of three maize inbred lines grown at 24 °C/22 °C (control, day 0, green background), then the plants were transferred to 14 °C/12 °C for four days (acclimation, days 1 and 5, yellow background), and finally to 8 °C/6 °C for four days (severe cold, days 6 and 10, pink background). Alternatively, plants were transferred directly from 24 °C/22 °C to 8 °C/6 °C (pink background, broken lines). Data are means ± SD for three independent experiments with 3 - 5 plants per experiment