## 3 Results
### Morphological Studies
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Treatment**} & **Physical** & **Shoot** & **Leaf** & **Shoot** & **Leaf** & **Leaf** & **Leaf** & **Petiole** \\  & **Parameter** & **Length** & **Number** & **Pa Week** & **Diameter** & **Length** & **Width** & **Area** & **Length** \\ \hline \multirow{2}{*}{MW/control EC} & BD & 0.4667 & 0.2848 & 0.6429 & 0.4736 & 0.4376 & 0.4431 & 042.53 \\ \cline{2-9}  & WHC & 0.2255 & 0.8476 * & 0.3794 & 0.7326 & 0.6361 & 0.7273 & 0.8508 * \\ \hline \multirow{2}{*}{L/control EC} & BD & \(-\)0.0145 & \(-\)0.5190 * & \(-\)0.8082 * & \(-\)0.7648 * & \(-\)0.5544 & \(-\)0.6573 * & \(-\)0.7552 * \\ \cline{2-9}  & WHC & 0.1066 & 0.2659 & \(-\)0.1366 & \(-\)0.0405 & 0.0168 & \(-\)0.0039 & \(-\)0.0232 \\ \hline \multirow{2}{*}{MW/high EC} & BD & 0.4017 & 0.0680 & 0.4244 & 0.3765 & 0.3124 & 0.3360 & 0.3283 \\ \cline{2-9}  & WHC & 0.3186 & 0.7968 * & 0.3476 & 0.6339 & 0.4884 & 0.6060 & 0.8594 * \\ \hline \multirow{2}{*}{L/high EC} & BD & 0.3348 & 0.6103 & \(-\)0.2252 & 0.3156 & 0.2001 & 0.3115 & 0.5180 \\ \cline{2-9}  & WHC & 0.3143 & 0.8402 * & 0.0748 & 0.6068 & 0.4080 & 0.5651 & 0.6967 \\ \hline \hline \end{tabular}  
* significant at \(p\leq 0.05\).  
\end{table} 
Table 2: Linear correlation coefficient(\({}^{x}\)) between selected morphological parameters of cucumber and physical properties of medium (BD, WHC) depending on medium type and medium EC. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{2}{c}{**MW/Control EC**} & \multicolumn{2}{c}{**L/Control EC**} & \multicolumn{2}{c}{**MW/High EC**} & \multicolumn{2}{c}{**L/High EC**} \\ \cline{2-9}  & **R** & **D (\%)** & **R** & **D (\%)** & **R** & **D (\%)** & **R** & **D (\%)** \\ \hline Stem length increase per week & 0.4672 & 21.82 & 0.4263 & 18.17 & 0.1245 & 1.55 & 0.3412 & 11.64 \\ \hline Leaf number per week & 0.8671 * & 75.19 & 0.8749 * & 76.54 & 0.7393 * & 54.71 & 0.8543 * & 72.98 \\ \hline Diameter shoot & 0.6451 & 41.62 & 0.4546 & 20.67 & 0.8366 * & 69.99 & 0.5194 & 26.98 \\ \hline Leaf length & 0.7406 & 54.85 & 0.6576 & 43.24 & 0.8223 * & 67.62 & 0.6937 & 48.12 \\ \hline Leaf width & 0.6483 & 42.03 & 0.4962 & 24.62 & 0.6166 & 38.02 & 0.4771 & 22.76 \\ \hline Leaf area & 0.7312 & 53.47 & 0.6027 & 36.32 & 0.7198 * & 51.81 & 0.6312 & 39.84 \\ \hline Petiole length & 0.8510 * & 72.43 & 0.8650 * & 74.83 & 0.8188 * & 67.05 & 0.7049 & 32.91 \\ \hline \hline \end{tabular}  
* significant at \(p\leq 0.05\). D \(<\) 25%—low impact, 25-45%—average impact, 46-100%—high impact.  
\end{table} 
Table 3: Multiple correlation coefficient (R) and coefficient of determination (D) for selected morphological parameters of cucumber plants and type of medium and EC. In cucumbers grown in lignite substrate, a significant negative correlation was found between the physical properties of the medium, both BD and WHC, and the leaf concentrations of macronutrients such as calcium and sulfate. Significant correlations were found mainly when lignite was fertilized with high EC medium (Table 4), which was confirmed by multiple correlation analysis and coefficient of determination for these parameters (Table 5). The concentration of calcium, and especially sulfur, in cucumber leaves was higher when plants were grown in lignite substrate than in mineral wool, irrespective of the EC ion concentration of the medium. On the other hand, the concentration of magnesium in cucumber leaves depended more on the concentration of Mg ions in the capillary medium than on the characteristics of the medium because both when cucumber was grown in mineral wool and in lignite mats, more magnesium was in the leaves when plants were fertilized with high EC medium (Table S1 Supplementary Materials).