## 3 Results  
### Plant Growth and Biomass Yield  
The temporal patterns of fresh weight for each species are shown in Figure 1. _Tetragonia_ showed similar growth rates in moderate-salinity conditions, with an increase in plant final biomass of 27.4% and of 47.8% in M-SW and M-SA, respectively, compared to the control. However, high-salinity treatment determined a significant growth reduction compared to both moderate-salinity conditions and control. No significant differences were observed in growth rate in _Tetragonia_ due to the type of salinity stress (i.e., M-SW vs. M-SA and H-SW vs. H-SA). On the other hand, the response of lettuce followed a decreasing trend in accordance with increasing salinity: in particular, all salinity treatments significantly decreased the plants' growth compared to that of the control (i.e., 27% and 32% in M-SW and M-SA, respectively), with no significant differences found between the stress types under moderate stress conditions. However, under high salinity, a significantly stronger growth reduction was observed in H-SA (83%) compared to that in H-SW (62%) treatment.  
The dry biomass weight of the plants at the end of the cycle is shown in Table 2.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Treatment** & _Tetragonia_ **g** & **Lettuce g** \\ \hline C & 12.6 \(\pm\) 0.6 \({}^{\text{a}}\) & 8.2 \(\pm\) 0.3 \({}^{\text{a}}\) \\ M-SW & 17.4 \(\pm\) 3.4 \({}^{\text{a}}\) & 6.7 \(\pm\) 0.4 \({}^{\text{a}}\) \\ M-SA & 16 \(\pm\) 1.9 \({}^{\text{a}}\) & 6.8 \(\pm\) 0.4 \({}^{\text{a}}\) \\ H-SW & 2.5 \(\pm\) 1.2 \({}^{\text{b}}\) & 4.4 \(\pm\) 0.2 \({}^{\text{b}}\) \\ H-SA & 2.1 \(\pm\) 0.5 \({}^{\text{b}}\) & 2.4 \(\pm\) 0.6 \({}^{\text{c}}\) \\ \hline \hline \end{tabular} Values are single plants weight means (\(n=4\)) \(\pm\) SEM expressed in grams. Different letters indicate significant differences assessed at \(p<0.05\) ([PERSON]’s test).  
\end{table}
Table 2: The dry weight of whole plants at harvest.  
Figure 1: The fresh weight of whole _Tetragonia_ (**a**) and lettuce (**b**) plants. Values are single plants’ weight means (\(n=4\)) \(\pm\) SEM expressed in grams. Different letters at the final sampling indicate significant differences assessed at \(p<0.05\) ([PERSON]’s test).  
In the case of _Tetragonia_, we found the same differences among treatments as observed for fresh weight. Regarding lettuce, unlike fresh weight, the dry biomass of plants grown under moderate salinity conditions was not significantly different from that of the control. However, under high-salinity treatments we observed the same response as in fresh weight: a significant reduction in dry weight determined by H-SA treatment compared to H-SW treatment was observed.  
The commercial yield of the two species (i.e., shoot fresh weight) is reported in Figure 2. The shoot production of _Tetragonia_ was enhanced, although not significantly, by both moderate-salinity treatments: an increase of 59.7% and of 55.2% was observed for M-SW and M-SA, respectively. The crop yield showed a significant and severe decrease under both high-salinity treatments. In lettuce, all treatments resulted in a significant reduction in commercial yield compared to that of control. Both medium-salinity stress conditions resulted in 32% (M-SW) and 38% (M-SA) yield reduction compared to control. Under higher-stress conditions a significant yield reduction due to NaCl treatment compared to the seawater was also observed, with H-SA treatment showing 86% and H-SW showing 68.5% yield reductions.