## 4 Discussion  
In our experiment, tree water status did not affect the biometric parameters measured in the branchlets (number of nuts per branchlet, fresh and dry weight of nuts and kernels); similar results have been reported by previous studies on pistachio [17; 25; 26; 37]. In this species, irrigation generally affects yield by increasing the percentages of bearing and nonbearing shoots within a canopy rather \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Fatty Acids** & **Level 0 (\%)** & **Level 1 (\%)** & **Level 2 (\%)** \\ \hline Myristic acid C14:0 & 0.1 \(\pm\) 0.00 ns & 0.1 \(\pm\) 0.00 & 0.1 \(\pm\) 0.00 \\ Palmitic acid C16:0 & 9.8 \(\pm\) 0.07 ns & 9.6 \(\pm\) 0.22 & 9.6 \(\pm\) 0.10 \\ Palmitoleic acid C16:1 & 0.8 \(\pm\) 0.06 ns & 0.8 \(\pm\) 0.06 & 0.8 \(\pm\) 0.06 \\ Stearic acid C18:0 & 1.9 \(\pm\) 0.32 ns & 2.1 \(\pm\) 0.37 & 2.2 \(\pm\) 0.18 \\ Oleic acid C18:1 & 70.1 \(\pm\) 1.83 ns & 71.5 \(\pm\) 1.96 & 71.1 \(\pm\) 0.73 \\ Vaccenic acid C18:1 & 2.1 \(\pm\) 0.03 ns & 2.0 \(\pm\) 0.13 & 2.0 \(\pm\) 0.11 \\ Linoleic acid C18:2 & 14.4 \(\pm\) 2.23 ns & 13.2 \(\pm\) 1.98 & 13.5 \(\pm\) 0.85 \\ Linolenic acid C18:2 & 0.2 \(\pm\) 0.01 ns & 0.2 \(\pm\) 0.00 & 0.2 \(\pm\) 0.03 \\ Arachidic acid C20:0 & 0.2 \(\pm\) 0.01 ns & 0.2 \(\pm\) 0.01 & 0.2 \(\pm\) 0.01 \\ Gondoic acid 20:1 & 0.4 \(\pm\) 0.07 ns & 0.4 \(\pm\) 0.05 & 0.4 \(\pm\) 0.04 \\ \hline \hline \end{tabular} Values are express as mean \(\pm\) SD (n = 3). ns, not significant (\(p>0.05\)).  
\end{table} 
Table 4: Fatty acid composition (percentage in oil, %) of kernels affected by different levels of water stress. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Volatile** & **Level 0** & **Level 1** & **Level 2** & \multicolumn{1}{c}{**Odor Treshold**} \\
**Compounds** & **(\(\mu\)g/g)** & **(\(\mu\)g/g)** & **(\(\mu\)g/g)** & **Aromatic Descriptor** & **(ppb)** \\ \hline
**Terpenes** & & & & & \\ \(\alpha\)-Pinene & 35.0 \(\pm\) 4.39 b  & 33.1 \(\pm\) 1.98 ab  & 26.2 \(\pm\) 1.88 a  & pine, turpentine & 6 \\ Camphene & 0.8 \(\pm\) 0.39 ns  & 0.7 \(\pm\) 0.64 & 0.7 \(\pm\) 0.09 & vanilla & - \\ \(\beta\)-Pinene & 0.7 \(\pm\) 0.34 ns  & 0.5 \(\pm\) 0.28 & 0.5 \(\pm\) 0.05 & pine, resin, turpentine & 140 \\ \(\beta\)-Myrcene & 1.4 \(\pm\) 0.45 b  & 0.8 \(\pm\) 0.03 ab  & 0.6 \(\pm\) 0.14 a  & basamic, must, spice & 13 \\ 3-Carene & 0.6 \(\pm\) 0.46 ns  & 0.4 \(\pm\) 0.28 & 0.3 \(\pm\) 0.11 & lemon, resin & 77 \\ p-Cymene & 0.4 \(\pm\) 0.44 ns  & 0.3 \(\pm\) 0.24 & 0.3 \(\pm\) 0.02 & solvent, gasoline, citrus & 11 \\ D-limonene & 3.3 \(\pm\) 1.01 ns  & 2.8 \(\pm\) 0.45 & 2.8 \(\pm\) 0.68 & citrus, mint & 10 \\
2-Carene & 3.0 \(\pm\) 3.10 ns  & 2.5 \(\pm\) 1.44 & 1.8 \(\pm\) 0.40 & sweet, pine, cedar & - \\ \hline \hline \end{tabular} For the aromatic descriptors were used Flavornet and NIST (National Institute of Standards & Technology) websites. For the odor threshold values was used the LRI & Odour Database Values are express as mean \(\pm\) SD (n = 3). Values in the same row followed by different letters (a-b) indicate significant differences (Tukey’s test \(p\leq 0.05\)); ns, not significant (\(p>0.05\)).  
\end{table} 
Table 3: Volatile compounds (\(\mu\)g/g) of pistachio nuts, aromatic description and odor threshold (ppb) affected by different levels of water stress. than increasing the number of fruit per branch or fruits' weight [38]. The differences observed between 2014 and 2015 in nut biometric parameters presented in Table 1 are most likely associated with the alternate bearing behavior typical of pistachio [25; 26], since temperature patterns were very similar in both years. Water status had a positive and significant effect on chlorophylls content, as shown in Table 2. In general, water stress reduces leaf chlorophyll content [39; 40; 41] by the result of damage to chloroplasts caused by active oxygen species [42].