Leaf Ψ and P–V traits
The mixed models revealed that growth stage significantly influenced the relationship between DGW and Ψ pd,Ψ md, Ψpd -Ψmd (F =52.34, P <0.001;F =61.32, P <0.001; F =18.05,P <0.001, respectively). There were significant differences in the average Ψ pd andΨ md, as well as in the Ψpd -Ψmd values among the five sites during both the EGS and LGS (Fig. 2). There were also significant differences between the two growth stages within the same site (Fig. 3). Except theΨ pd during the LGS, branch Ψ s (Ψ pd and Ψ md) andΨ pd -Ψ md significantly decreased as DWG increased (Fig. 4). The assimilating branch Ψvalues at π 100 and Ψ TLP were significantly different among the sites (Fig. 5). The π100 ranged between -3.74 MPa (shallowest DGW) and -4.59 MPa (deepest DGW; EGS). TheΨ TLPranged between -4.14 MPa (shallowest DGW) and -5.00 MPa (deepest DGW; EGS). The π100 values ranged between -3.80 MPa (shallowest DGW) and -4.82 MPa (deepest DGW; LGS). TheΨ TLP ranged between -4.21 MPa (shallowest DGW) and -5.14 MPa (deepest DGW; LGS) (Fig. 5). There were no significant differences in π100 and Ψ TLPbetween the two growth periods at the same site (data not show here). The Ψ md values were generally less negative than the leaf Ψ at zero turgor. The mixed models revealed that growth stage had no significant influence on the relationship between DGW and π100, Ψ TLP (F =55.80,P <0.001; F =60.97, P <0.001, respectively). However, there was a decreasing trend of Ψ at π100 and Ψ TLP along with groundwater depth irrespective of the growth stage (Fig. 6).