While, the IIS had a high significant effect on the averages of WUE (kg m-3) and IWUE
(kg m-3) compared to ICS treatment Table 5.
The instantaneous water use efficiency (WUE) was obtained by the relation between the net photosynthetic rate and the transpiration (A/E) and the intrinsic water use efficiency (iWUE
) was obtained by the ratio between the net photosynthetic rate and the stomatal conductance (A/[g.sub.s]).
Although the genotypes had differences in A, gs, and E, they had similar results of instantaneous water use efficiency (WUE), and intrinsic water use efficiency (IWUE
All leaf-level parameters ([A.sub.sat], [g.sub.s], and iWUE
) were multiplied by the crown leaf area to scale up to the crown level.
WUE was not influenced significantly by the irrigation depths, unlike the irrigation water use efficiency (IWUE
), which showed a significant response, with the highest (266.2 kg [ha.sup.-1] [mm.sup.-1] in 2014, 269.7 kg [ha.sup.-1] [mm.sup.-1] in 2015) and lowest (147.5 kg [ha.sup.-1] [mm.sup.-1] in 2014, 172.4 kg [ha.sup.-1] [mm.sup.-1] in 2015) values observed, respectively, for L4 and L1 (Figure 7).
The initial level of stomatal conductance ([g.sub.s]; Figure 2(a)) and instantaneous water use efficiency (IWUE
; Figure 2(b)) was almost similar for all treatments.
Irrigation water use efficiency (IWUE
) is the ratio of yield and the total irrigation water volume.
Effects of stress treatments on irrigation water use efficiency (IWUE
In this study the term irrigation water use efficiency (IWUE
) was used instead of the traditional water use efficiency (WUE).
cannifolium values of A, [g.sub.s] and IWUE
measured during the rainy season at 350 [micron]mol x [mol.sup.-1] C[O.sub.2] were not significantly different between SC and AC (Fig.
Before the 8-d treatments (52 DAS), leaf Amax and IWUE
were higher and [g.sub.s], E, SI, STD, and [Psi]s were lower in e[CO.sub.2] than in a[CO.sub.2] (Table 2).
As a function of PPFD, the net assimilation rate of C[O.sub.2] (A), stomatal conductance (gs), internal C[O.sub.2] concentration (Ci) and leaf transpiration rate (E) were determined according to (ZHANG et al., 2001), where WUE corresponds to the efficiency of water use, iWUE
is the intrinsic efficiency of water use and Fc is the carboxylation efficiency.