## 3 Results and Discussion
For tomato seeds, which are often sensitive to low temperatures, the ability to germinate efficiently under cold stress conditions is essential for early-season planting or cultivation in cooler climates. An enhanced cold tolerance during germination not only improves the seedling vigor and uniformity but also reduces the risk of seed decay and disease, which are more prevalent in slower-germinating seeds. Furthermore, successful germination under cold stress can extend the growing season, increase the yield potential, and offer growers greater flexibility in planting schedules [25; 26; 27]. Tomato seeds were kept in two different environmental conditions, 7 days at 10 \({}^{\circ}\)C and 5 days at 24 \({}^{\circ}\)C, to determine their germination ability under cold stress. Both the control and PEF-treated samples showed no germination for 7 days at 10 \({}^{\circ}\)C; however all samples showed germination for 5 days at 24 \({}^{\circ}\)C. While the germination rate for the control samples was 22.22 \(\pm\) 1.92%, the germination rate for the PEF-treated samples ranged from 12.22 \(\pm\) 1.92% to 46.67 \(\pm\) 3.33%. The germination rate of the PEF-treated samples by 1.92, 5.76, 10.88, 15.36, and 17.28 J was significantly higher than that of the control samples (\(p\leq 0.05\)) (Table 4). Electrical conductivity (EC) is a critical parameter in assessing the quality and viability of tomato seeds, as it reflects the integrity of seed membranes. High EC values indicate an increased leakage of electrolytes, typically resulting from damaged or deteriorated seed membranes. This leakage is associated with reduced seed vigor, lower germination rates, and a decreased seedling growth potential. Therefore, monitoring EC provides valuable insights into the physiological state of tomato seeds, enabling the early detection of deterioration and supporting the better management of seed storage and handling practices [18; 28]. \begin{table}
\begin{tabular}{c c} \hline
**Energy (J)** & **Normal Seedling Rate (\%)** \\ \hline  
\hline \end{tabular} Note 1: Data in the same column with different superscript letters are significantly different (\(p\leq 0.05\)). Note 2: The data is presented as the mean \(\pm\) standard deviation.  
\end{table} 
Table 3: The normal seedling rate (%) of the control and the PEF-treated tomato seed samples. The EC values of the control tomato seed samples measured at 4, 8, and 24 h after the PEF treatment were 75.29 \(\pm\) 1.88, 77.16 \(\pm\) 2.38, and 86.04 \(\pm\) 5.12 \(\upmu\)S/cm\(\cdot\)g, respectively. The EC of PEF-treated tomato seeds did not exhibit a consistent increasing or decreasing trend with rising energy levels, but a general increase was observed over time following the treatment. The lowest EC values among PEF-treated seeds were recorded at 3.21 J as 59.67 \(\pm\) 4.21, 60.67 \(\pm\) 4.13, and 65.38 \(\pm\) 5.41 \(\upmu\)S/cm\(\cdot\)g at 4, 8, and 24 h, respectively. In contrast, the highest EC values were observed at 2.16 J as 81.34 \(\pm\) 4.25, 84.51 \(\pm\) 4.22, and 92.72 \(\pm\) 9.51 \(\upmu\)S/cm\(\cdot\)g at the same time points. As the measurement time increased, the EC values of both the control and PEF-treated samples significantly rose (\(p\leq\) 0.05). Although some PEF-treated samples exhibited EC values close to those of the control, these differences were not statistically significant after 24 h (Table 5). The salt stress tolerance in tomato seeds refers to the ability of seeds to germinate and grow under saline conditions, which is a crucial trait for ensuring crop productivity in areas affected by soil salinity. High salt concentrations can disrupt the water uptake, induce osmotic stress, and cause ion toxicity, leading to reduced seed germination, poor seedling development, and an overall plant growth inhibition. Tomato seed varieties with higher salt tolerances can better maintain their cellular homeostasis, osmotic balance, and ion compartmentalization under saline stress.