Fig. 1.
Basic parameters of photosynthetic apparatus efficiency in cold-treated maize. Maximal quantum yield of PS II, Fv/Fm (upper lines), and effective quantum yield of PS II, ΦPSII (lower lines), of the 3rd leaf of ETH-DH7 (solid) and ETH-DL3 (dashed) plants grown at 24/22 °C (control, day 0) and plants treated with 8/6 °C for 14 h (night + 4 h of light), 28 h (two full photoperiods + 4 h of light) or for 124 h (five full photoperiods + 4 h of light). Data are means for 9 plants ± SD. For Fv/Fm comparisons between inbred lines, temperatures, and interaction of line and temperature effects the p values were 0.0001, 0.0001 and 0.0445, respectively; for ΦPSII comparisons the respective p values were 0.0001, 0.0001 and 0.0211