## 3 Results and Discussion
### Antioxidant Activity and Compounds
In particular, the non-salinized untreated plants (EC0 \(\times\) BC treatment) recorded the highest and lowest values for HAA and ABTS AA assays, respectively, whereas an opposite trend was observed for plants that were grown under mid- to high-salinity levels and did not receive any biostimulant application (EC4 \(\times\) BC). This result is in agreement with the findings of [PERSON] et al. [56], who also suggested that non-salinized lettuce plants had the highest HAA, while [PERSON] et al. [16] also reported a contrasting response of spinach plants to salinity stress and biostimulant application in regard to HAA and ABTS AA assays. Regarding total phenols and TAA content, no specific trends were recorded since no significant differences were recorded between most of the treatments, although the lowest overall content was recorded for the highest salinity level and the plants treated with the Trainer@biostimulant; however, [PERSON] et al. [16] suggested a significant decrease in total phenols and TAA content for spinach plants treated with a legume-derived protein hydrolysate, whereas increasing salinity resulted in an increase in total phenol content and had no effect on TAA content. On the other hand, [PERSON] et al. [36] noted a beneficial effect of biostimulant application on the total phenol content of spinach plants. According to [PERSON] et al. [53], no significant effects of salinity on the total phenol content, as well as the lipophilic and hydrophilic antioxidant activity, of lettuce plants grown under salinity stress were noted, while the same authors suggested fluctuating trends for TAA content. Table 3 presents the effect of salinity level and harvesting time on HAA, the ABTS assay, and total ascorbic acid content in \(D\). _tenuifolia_ leaves, regardless of biostimulant application. HAA varied depending on the salinity level and the harvesting time, with the highest overall value being recorded for the non-salinized plants and the fourth harvesting time, whereas the highest salinity level and late harvesting (EC6 \(\times\) VI) resulted in the lowest values for this particular assay. On the other hand, the EC6 \(\times\) II and EC0 \(\times\) VI treatments resulted in the highest and lowest values for the ABTS assay. Total phenol \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Treatment**} & \multicolumn{2}{c}{**HAA**} & **ABTS AA** & \multirow{2}{*}{**Total Phenols mg**} & **TAA** \\  & **mmol Ascorbic Acid** & & **mmol Trolox** & & **Aallic Acid g\({}^{-1}\) dw** & **Total Ascorbic Acid** \\  & **equ. 100 g\({}^{-1}\) dw** & & **equ. 100 g\({}^{-1}\) dw** & & **mg 100 g\({}^{-1}\) fw** \\ \hline EC0 & BC & 10.17 \(\pm\) 0.44 a & 10.09 \(\pm\) 0.62 d & 2.29 \(\pm\) 0.08 ab & 32.88 \(\pm\) 7.05 a \\  & BA & 9.75 \(\pm\) 0.30 a–c & 11.49 \(\pm\) 0.35 b–d & 2.19 \(\pm\) 0.08 a–c & 30.27 \(\pm\) 8.00 ab \\  & BT & 9.70 \(\pm\) 0.45 a–c & 12.34 \(\pm\) 0.57 a-c & 2.37 \(\pm\) 0.09 a & 27.29 \(\pm\) 5.42 a–c \\ EC2 & BC & 8.52 \(\pm\) 0.32 d–f & 11.61 \(\pm\) 0.70 b–d & 2.31 \(\pm\) 0.12 a–c & 26.31 \(\pm\) 5.40 a–c \\  & BA & 9.89 \(\pm\) 0.32 ab & 10.86 \(\pm\) 0.56 cd & 2.32 \(\pm\) 0.09 a & 31.88 \(\pm\) 5.75 a \\  & BT & 9.11 \(\pm\) 0.25 b–d & 12.32 \(\pm\) 0.51 a–c & 2.40 \(\pm\) 0.07 a & 32.37 \(\pm\) 8.23 a \\ EC4 & BC & 7.95 \(\pm\) 0.40 f & 13.88 \(\pm\) 0.66 a & 2.41 \(\pm\) 0.11 a & 22.85 \(\pm\) 4.75 bc \\  & BA & 8.93 \(\pm\) 0.31 c–e & 12.69 \(\pm\) 0.36 ab & 2.07 \(\pm\) 0.11 bc & 26.74 \(\pm\) 4.53 a–c \\  & BT & 8.59 \(\pm\) 0.28 d–f & 12.14 \(\pm\) 0.41 a–c & 2.27 \(\pm\) 0.10 ab & 30.63 \(\pm\) 4.60 ab \\ EC6 & BC & 8.10 \(\pm\) 0.36 ef & 11.73 \(\pm\) 0.67 b–d & 2.28 \(\pm\) 0.05 ab & 23.52 \(\pm\) 2.52 bc \\  & BA & 8.62 \(\pm\) 0.38 d–f & 13.19 \(\pm\) 0.77 ab & 2.21 \(\pm\) 0.12 a–c & 22.57 \(\pm\) 4.47 bc \\  & BT & 8.21 \(\pm\) 0.35 ef & 12.55 \(\pm\) 0.43 a–c & 2.03 \(\pm\) 0.08 c & 19.75 \(\pm\) 2.82 c \\ \hline \hline \end{tabular}
\end{table}