Figure 4. Effects of root chilling on the photosynthetic gas exchange of leaves.

The responses of transpiration rate (E; a–c), stomatal conductance (Gs; d–f) and net photosynthetic rate (Pn; g–i) in JC-4 leaves to PEG (polyethylene glycol, 30%, W/W) shock at 25 °C (a,d,g) and chilling shock (6 °C; b,c,e,f,h,i) of root. The plants were grown in Hoagland nutrient solution (a,b,d,e,g,h) or soil (c,f,i). The arrowheads indicate the start of shock. The gas exchange in the leaves was measured at 800 μmol mol⁻¹s light, 25 °C, 400 μmol mol⁻¹ CO₂ concentration and 60–65% relative humidity. Each data point is the average of 4 independent plants. The results for the chilling-tolerant cucumber variety JY-3 were similar to those of the JC-4 (Supplementary Fig. S2).