## 3 Results
### Leaf Functionality and Tree Water Relations
#### 3.3.2 Season 2016  
At 92 DAFB, when water supply was the same for all the treatments, no differences were recorded in terms of cumulative photoassimilation, transpiration and water stress integral; the average VPD and air temperature during the period of measure (9:00-17:00) were about 2.0 kPa and 29.4 \({}^{\circ}\)C, respectively; the midday stem water potential was \(-\)0.6 MPa and the average gs was about 0.182 mol m\({}^{-2}\) s\({}^{-1}\). At pit hardening (107 DAFB), \(\Sigma\)Pn, \(\Sigma\)Tr and S\({}_{\Psi}\) were similar among the treatments (Figure 5; Table S1). Average air temperature and VPD were 29.6 \({}^{\circ}\)C and 2.4 kPa, respectively; the midday stem water potential was \(-\)0.8 MPa and the average gs was 0.115 mol m\({}^{-2}\) s\({}^{-1}\). At the beginning of fruit cell expansion (12 July, 124 DAFB), the average VPD was about 4.5 kPa and air temperature 37.6 \({}^{\circ}\)C. T and F showed the highest \(\Sigma\)Pn (around 0.23 mol m\({}^{-2}\)), while the lowest one was recorded on S (\(\sim\)0.15 mol m\({}^{-2}\)). M revealed an intermediate \(\Sigma\)Pn of 0.18 mol m\({}^{-2}\) (Figure 5A; Table S1). The highest cumulative transpiration was recorded on F (146.1 mol m\({}^{-2}\)), followed by T (127.0 mol m\({}^{-2}\)); the lowest \(\Sigma\)Tr was observed in M and S with an average cumulative transpiration of 89.8 mol m\({}^{-2}\) (Figure 5B). The average gs during the period of measure was about 0.107 mol m\({}^{-2}\) s\({}^{-1}\) for T and F and 0.073 mol m\({}^{-2}\) s\({}^{-1}\) for M and S. F and T had a quite similar water stress integral (\(-\)3.9 GPa), higher than S\({}_{\Psi}\) recorded in S and M of about \(-\)12 GPa (Figure 5C). The midday stem water potential was \(-\)1.0 MPa for T and F, and \(-\)1.3 MPa for S and M. At the fruit cell expansion stage (135 DAFB), the average air temperature and vapor pressure deficit recorded during the period of measure were about 32.5 \({}^{\circ}\)C and 2.8 kPa, respectively. M and F showed \(\Sigma\)Pn and \(\Sigma\)Tr higher than T and S (Figure 5A,B; Table S1). The average gs recorded from 9:00 to 17:00 was about 0.118 mol m\({}^{-2}\) s\({}^{-1}\) in M and F, and 0.098 mol m\({}^{-2}\) s\({}^{-1}\) in T and S. The water stress integral was \(-\)7.8 GPa in T, followed by M (\(-\)10.6 GPa); S and R had the lowest S\({}_{\Psi}\) of about \(-\)14.8 GPa (Figure 5C; Table S1). The midday stem water potential at 135 DAFB was about \(-\)1.0 MPa in T, \(-\)1.1 MPa in M and \(-\)1.3 MPa in F and S. Close to the harvest (163 DAFB), the average T\({}_{\rm air}\) and VPD were 29.1 \({}^{\circ}\)C and 1.9 kPa, respectively. M showed a cumulative net photoassimilation and transpiration higher than T and S and the lowest values were observed in F (Figure 5A,B; Table S1). The average stomatal conductance followed the same trend with gs of 0.126 mol m\({}^{-2}\) s\({}^{-1}\) in M, about 0.099 mol m\({}^{-2}\) s\({}^{-1}\) in T and S, and 0.064 mol m\({}^{-2}\) s\({}^{-1}\) in F. S\({}_{\Psi}\) in M was \(-\)4.4 GPa, higher than T and S (\(-\)9.0 GPa); the lowest water stress integral was observed in F with S\({}_{\Psi}\) of \(-\)13.4 GPa (Figure 5C). The midday stem water potential followed the same trend with values of \(-\)1.4, \(-\)1.6, \(-\)1.6 and \(-\)1.8 MPa recorded in M, T, S and F, respectively.  
Figure 4: Cumulative leaf net photosynthesis (\(\Sigma\)Pn) (**A**), transpiration (\(\Sigma\)Tr) (**B**) and water stress integral (\(\
abla\)\(\
abla\)\(\
abla\)) (**C**) calculated for T (black bars), M (grey bars), F (dashed bars) and S (dotted bars) during the time of measure (9:00–17:00 h) of each day of measurement in 2015. Within the same date different letters indicate a statistical difference at \(p\leq 0.05\).