## 3 Results  
### Physiological Analysis  
To determine the physiological effect of drought-induced VOCs on co-located WW receiver vines, leaf stomatal conductance (\(g_{s}\)) of all the treatments was monitored at drought initiation (DI, Day 0), peak drought (PD, Day 8), and 24 h after re-watering (Day 9). At DI, all treatment vines were at FC (\(\sim\)23% VWC) and therefore no differences were noted in \(g_{s}\) (\(p\) > 0.05) (Table 2). After eight days of withholding water in the isolated and co-located drought-stressed treatments, DS\({}_{\rm c}\) and DS\({}_{\rm e}\), respectively, PD conditions were achieved. Soil moisture was significantly decreased in DS\({}_{\rm c}\) from 21 \(\pm\) 0.1% to 4 \(\pm\) 0.1%, and in the DS\({}_{\rm e}\) from 24 \(\pm\) 3.1% to 4 \(\pm\) 0.3%, consequently lowering the \(g_{s}\) of the vines from 91 \(\pm\) 8.3 mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\) to 33 \(\pm\) 3.9 mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\) in DS\({}_{\rm c}\) and 146 \(\pm\) 31.7 mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\) to 33 \(\pm\) 2.4 mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\) in DS\({}_{\rm e}\) at PD (\(p\) < 0.0001) (Table 2). Following re-watering on Day 8, the \(g_{s}\) of both treatments increased on Day 9 to 70 \(\pm\) 8.3 in DSc and 63 \(\pm\) 10.9 in DSe. The \(g_{s}\) and soil moisture values of WW\({}_{\rm c}\) vines were recorded once at DI and were similar to all treatments at DI. There were no significant differences in \(g_{s}\) of the well-watered receiver (WW\({}_{\rm r}\)) vines at any of the time points, indicating that their drought-stressed counterparts (DS\({}_{\rm e}\)) did not influence their \(g_{s}\). Soil moisture was kept at FC in the isolated and co-located well-watered vines and was not significantly different in both treatments. The canopy VPD of DS\({}_{\rm c}\) was higher than the VPD recorded for WW\({}_{\rm c}\) being 1.95 kPa and 1.42 kPa, respectively. The co-located treatment vines recorded a VPD of 1.93 kPa, which was similar to that of DS\({}_{\rm c}\) (\(p\) = 0.9788). \begin{table}
\begin{tabular}{c c c} \hline
**Gene Name/ID** & **Forward Primer Sequence** & **Reverse Primer Sequence** & **References** \\ \hline Allene synthase (AOS) & CTTCGGAGGGGATGAAAATCA & GGCTAATTGGGGTGTGCAGT & [36] \\ Chorismate synthase & & GCCTTCACATGCAGATGCCTA & CTGCAACTCTCCCAATGGTT & [37] \\ (CHORS) & ACCCACAAAATCGTTCCCACATTG & ACCTTTCGTTGTGTCTCCTCACTCTG & [38] \\ Lipoxygenase (VvLOX) & ACCCACAAAATCGTTCCCACATTG & ACCTCTTCGTGTCTCGTCCACTCTG & [38] \\ \(\alpha\)-Pinee & & TTGAGAAGCTTAAGGGAGATG & GGTAGCCATGCCTGTTCTAGG & [39] \\ \hline \end{tabular}
\end{table} 
Table 1: List of qPCR primers used in this study. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Treatments** & \(g_{s}\) **(mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\))** & \multicolumn{3}{c}{**Soil Moisture (\% VWC)**} \\ \hline  & Day 1 & Day 8 & Day 9 & Day 1 & Day 8 & Day 9 \\ WWc & 121 \(\pm\) 25.5 a & - & - & 21 \(\pm\) 0.07 a & - & - \\ DSc & 91 \(\pm\) 8.3 a\(\alpha\) & 33 \(\pm\) 3.9 b\(\beta\) & 70 \(\pm\) 8.3 a\(\alpha\) & 21 \(\pm\) 0.1 a\(\alpha\) & 4 \(\pm\) 0.1 a\(\beta\) & 23 \(\pm\) 0.6 a\(\alpha\) \\ DSe & 146 \(\pm\) 31.7 a\(\alpha\) & 33 \(\pm\) 2.4 b\(\beta\) & 63 \(\pm\) 10.9 a\(\alpha\) & 24 \(\pm\) 3.1 a\(\alpha\) & 4 \(\pm\) 0.3 a\(\beta\) & 24 \(\pm\) 2.9 a\(\alpha\) \\ WWr & 116 \(\pm\) 19.9 a\(\alpha\) & 100 \(\pm\) 24.79 a\(\alpha\) & 115 \(\pm\) 24.0 a\(\alpha\) & 23 \(\pm\) 0.9 a\(\alpha\) & 25 \(\pm\) 1.5 a\(\alpha\) & 25 \(\pm\) 1.5 a\(\alpha\) \\ \hline \end{tabular}
\end{table} 
Table 2: Physiological data collected from well-watered and drought-stressed treatment plants on stomatal conductance \(g_{s}\) (mmol H\({}_{\rm 2}\)O m\({}^{-2}\) s\({}^{-1}\)) and soil moisture, VMC (%), \(n\) = 3. Data were collected at drought initiation (Day 0), peak drought (Day 8), and 24 h after re-watering (Day 9). Values represent the mean \(\pm\) SEM for all the treatments.