FIGURE 2.

Effect of mechanical wounding on gas exchange in the local and the systemic leaves of wheat under freezing stress. Pn, photosynthetic rate; Gs, leaf stomatal conductance; Ci, internal CO₂ content; Tr, transpiration rate. The local (fifth) leaves were separately pre-treated with distilled water, 5 mM DMTU or 100 μM DPI prior to wounding. At 10 days after wounding, the seedlings were exposed to freezing stress for 24 h. After 24 h recovery, gas exchange parameters were measured on the systemic leaves with a portable photosynthesis system. Data are mean values ± SD of three independent replicates. Means denoted by different letters indicated significant difference at P < 0.05 according to Tukey’s test.