Figure 1. The tolerances of JY-3 and JC-4 when the detached leaf discs were treated with cool water under light.

The changes of the maximum quantum yield of PSII (Fv/Fm, a) the amount of PSI (b) the quantum yield of electron transfer through PSII (ΦPSII, c) and the non-photochemical quenching (NPQ, d) in detached leaf discs of JY-3 and JC-4 cucumber under chilling-light treatment for different periods of time. Leaf discs punched from fully expanded leaves were floated on the surface of cool water (6 °C), and the light intensity on the surface of the leaf discs was 150 μmol m⁻² s⁻¹. Values represent means ± SE, and each data point is the average of 10 independent plants. Different letters indicate significant differences between different cucumber varieties at P < 0.05.