FIGURE 3.

The involvement of NO in the maintenance of Fv/Fm of the system (fifth) leaf of cold stressed wheat plants by pre-wounding of the local (fourth) leaf. The systemic leaf was pre-treated with distilled water, 200 μM SNP, 200 μM L-NAME, 200 μM tungstate or 200 μM c-PTIO prior to wounded 8 h later. Fv/Fm was then determined by the systemic leaf as area of interest after 24 h freezing stress and one representative is shown. The horizontal false color code ranges from 0.0 (black) to 1.0 (red). Bar, 10 mm. Average values of Fv/Fm of systemic leaf by these treatments were also shown here. Data are means ± SD of three different replicates. Means denoted by the same letter did not significantly differ at P < 0.05 according to Tukey’s test.