Diurnal changes in (A) assimilation rate (<i>A</i>), (B) stomatal conductance (<i>g_s</i>), (C) intercellular CO₂ concentration (<i>C_i</i>), (D) transpiration rate (<i>E</i>) and (E) atmospheric vapour pressure deficit (VPD) (mean ± SE) in winter wheat under four treatments (CK, DS, DW and IW), as well as (F) photosynthetic photon flux density (PAR) (E) in anthesis stage.

<p><i>P</i> value represent the significance of the effects of each treatment.