## 3 Results
### Element, Phenolic Compounds and Proline Concentration in Edible Leaves  
Sodium (Na) concentration in edible leaves did significantly increase with increasing salinity in both species (Table 4), with both SA treatments leading to a higher accumulation of this element compared to the respective SW treatment. Salinity also led to a significant reduction in leaf potassium (K) concentration in both species, whereas calcium (Ca) accumulation followed different trends in the two species. In lettuce, this element significantly dropped in all treatments compared to the control whereas in _Tetragonia_ the H-SW treatment showed the same Ca concentration as the control, whereas in H-SA its concentration was significantly lower than that of the control (Table 4).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline  & & _Tetragonia_ & & & **Lettuce** & \\ \cline{2-7}
**Treatment** & **Na** & **K** & **Ca** & **Na** & **K** & **Ca** \\  & & **mg g\({}^{-1}\) DW** & & & & **mg g\({}^{-1}\) DW** & \\ \hline C & \(5.9\pm 2.2\,^{\circ}\) & \(63.8\pm 6\,^{\circ}\) & \(5.3\pm 0.4\,^{\circ}\) & \(1.5\pm 0.6\,^{\circ}\) & \(67.3\pm 7.1\,^{\circ}\) & \(5.5\pm 0.6\,^{\circ}\) \\ M-SW & \(84.4\pm 6.4\,^{\circ}\) & \(40.1\pm 4\,^{\circ}\) & \(37.0\pm 0.2\,^{\circ}\) & \(31.8\pm 1.6\,^{\circ}\) & \(54.5\pm 2.9\,^{\circ}\) & \(1.9\pm 0.2\,^{\circ}\) \\ M-SA & \(104.1\pm 4.9\,^{\circ}\) & \(34.1\pm 2.5\,^{\circ}\) & \(3.3\pm 0.1\,^{\circ}\) & \(46.5\pm 2.1\,^{\circ}\) & \(43.7\pm 1.2\,^{\circ}\) & \(1.6\pm 0.04\,^{\circ}\) \\ H-SW & \(126.6\pm 12.5\,^{\circ}\) & \(26\pm 2.6\,^{\circ\circ}\) & \(5\pm 0.7\,^{\circ\,\circ}\) & \(49.9\pm 1.7\,^{\circ}\) & \(43.8\pm 2.4\,^{\circ}\) & \(2.5\pm 0.1\,^{\circ}\) \\ H-SA & \(156.7\pm 7.2\,^{\circ}\) & \(10.6\pm 1.2\,^{\circ}\) & \(3.7\pm 0.2\,^{\circ\,\circ}\) & \(89.1\pm 8.5\,^{\circ}\) & \(28.1\pm 2\,^{\circ}\) & \(2.7\pm 0.1\,^{\circ}\) \\ \hline \end{tabular} Values are means (\(n=4\)) \(\pm\) SEM measured at the end of the crop cycles and expressed in mg per gram of dry weight. Different letters in the same column indicate significant differences assessed at \(p<0.05\) ([PERSON]’s test).  
\end{table}
Table 4: The Na, K and Ca concentration in edible leaves for different treatments.  
Figure 4: Photosynthetic rate (**A**,**C**) and stomata conductance (**B**,**D**) of the tested species. Values are means (\(n=4\)) \(\pm\) SEM measured during the crop cycles. Different letters indicate significant differences at the same recording day assessed at \(p<0.05\) ([PERSON]’s test).  
In _Tetragonia_, the concentration in phenolic compounds in edible leaves significantly decreased only for H-SA treatment, while it was comparable to the control in all the other salinity treatments (Figure 5). In lettuce, a significant increase compared to the control was observed in both high-salinity treatments ranging from 81% in H-SW to 130% H-SA.  
As shown in Table 5, the proline concentration in the edible leaves increased significantly at all salinity levels in _Tetragonia_, whereas this occurred only for the higher NaCl treatment in lettuce.  
In _Tetragonia_, the proline concentration in leaves was significantly higher under either salinity treatment in comparison to the control, but no significant differences among moderate and high salinity or between seawater and NaCl treatments were found. In lettuce, H-SA treatment led to a higher (and only significant) increase in proline concentration, whereas M-SA led to an increase of about four times and H-SW of almost seven times.