## 3 Results and Discussions
### Anatomical Analysis of Leaves by Light Microscopy  
The transverse section of Untreat leaves shows a large central vein and a thin leaf mesophyll (125.05 \(\pm\) 2.62 \(\upmu\)m) (Figure 1A). The central vein consists of a large microvascular bundle immersed in a parenchyma and surrounded, in the adaxial and abaxial part, by a collenchyma tissue. The foliar mesophyll appears to be made up of 2-3 layers of palisade tissue cells with an average thickness of 75.54 \(\pm\) 6.21 \(\upmu\)m (Figure 1A). The spongy tissue is on average 23.28 \(\pm\) 1.36 \(\upmu\)m thick (Figure 1B). The palisade tissue represents \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Time** & **T** & **N (g/kg)** & **P (g/kg)** & **K (g/kg)** & **Mg (g/kg)** & **Ca (g/kg)** & **S (g/kg)** \\ \hline \multirow{4}{*}{t1} & Treat 1 & 29.78 \(\pm\) 2.05 c & 1.41 \(\pm\) 0.07 b & 8.00 \(\pm\) 0.07 a & 3.56 \(\pm\) 0.15 b & 22.67 \(\pm\) 5.07 a & 1.48 \(\pm\) 0.13 c \\  & Treat 2 & 39.58 \(\pm\) 2.34 a & 1.44 \(\pm\) 0.01 b & 7.93 \(\pm\) 0.08 a & 4.80 \(\pm\) 0.37 ab & 28.40 \(\pm\) 1.53 a & 2.08 \(\pm\) 0.20 b \\  & Treat 3 & 33.62 \(\pm\) 2.16 bc & 1.60 \(\pm\) 0.07 ab & 7.90 \(\pm\) 0.25 a & 6.60 \(\pm\) 1.21 a & 30.13 \(\pm\) 2.50 a & 1.91 \(\pm\) 0.18 b \\  & Treat 4 & 36.84 \(\pm\) 3.32 ab & 1.78 \(\pm\) 0.16 a & 7.95 \(\pm\) 0.01 a & 6.25 \(\pm\) 1.32 ab & 30.45 \(\pm\) 5.60 a & 2.67 \(\pm\) 0.24 a \\  & Untreat & 37.91 \(\pm\) 2.56 ab & 1.39 \(\pm\) 0.16 b & 7.93 \(\pm\) 0.05 a & 5.42 \(\pm\) 0.83 ab & 33.36 \(\pm\) 5.06 a & 1.90 \(\pm\) 0.12 bc \\ \hline \multirow{4}{*}{t2} & Treat 1 & 27.55 \(\pm\) 1.39 b & 1.70 \(\pm\) 0.21 b & 7.45 \(\pm\) 0.25 a & 5.72 \(\pm\) 1.22 b & 30.96 \(\pm\) 5.24 b & 2.03 \(\pm\) 0.14 a \\  & Treat 2 & 35.14 \(\pm\) 0.86 a & 1.50 \(\pm\) 0.01 b & 7.20 \(\pm\) 0.29 a & 7.89 \(\pm\) 0.96 ab & 39.84 \(\pm\) 4.80 ab & 2.31 \(\pm\) 0.17 a \\ \cline{1-1}  & Treat 3 & 34.00 \(\pm\) 2.06 a & 2.06 \(\pm\) 0.06 a & 7.35 \(\pm\) 0.33 a & 7.46 \(\pm\) 0.38 ab & 37.36 \(\pm\) 0.94 ab & 2.12 \(\pm\) 0.18 a \\ \cline{1-1}  & Treat 4 & 33.81 \(\pm\) 0.74 a & 1.69 \(\pm\) 0.08 b & 6.88 \(\pm\) 0.39 a & 9.07 \(\pm\) 0.99 a & 42.61 \(\pm\) 4.08 ab & 2.36 \(\pm\) 0.19 a \\ \cline{1-1}  & Untreat & 35.17 \(\pm\) 1.62 a & 1.41 \(\pm\) 0.07 b & 6.76 \(\pm\) 0.09 a & 9.7 \(\pm\) 0.12 a & 45.44 \(\pm\) 3.60 a & 2.15 \(\pm\) 0.16 a \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Macro- and meso-elements composition of leaves at the two sampling dates. In column and for each period, different letters indicate significant differences (\(p<\) 0.05). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Time** & **Treatment** & **B** & **Zn** & **Fe** & **Mn** \\ \hline \multirow{4}{*}{t1} & Treat 1 & 65.04 \(\pm\) 4.66 b & 113.17 \(\pm\) 22.51 c & 218.27 \(\pm\) 25.44 a & 60.61 \(\pm\) 10.45 a \\  & Treat 2 & 66.96 \(\pm\) 5.03 b & 137.92 \(\pm\) 18.02 bc & 151.31 \(\pm\) 17.70 bc & 43.65 \(\pm\) 17.2 a \\  & Treat 3 & 77.01 \(\pm\) 6.70 b & 173.47 \(\pm\) 19.2 b & 192.20 \(\pm\) 3.15 c & 4.04 \(\pm\) 2.40 a \\  & Treat 4 & 112.80 \(\pm\) 5.80 a & 246.08 \(\pm\) 23.11 a & 186.69 \(\pm\) 14.69 ab & 54.48 \(\pm\) 5.446 a \\  & Untreat & 79.23 \(\pm\) 11.84 b & 124.69 \(\pm\) 15.17 c & 114.51 \(\pm\) 2.77 c & 32.27 \(\pm\) 1.33 a \\ \hline \multirow{4}{*}{t2} & Treat 1 & 11.65 \(\pm\) 45.34 ab & 49.31 \(\pm\) 9.55 bc & 145.87 \(\pm\) 11.23 a & 58.93 \(\pm\) 11.11 b \\  & Treat 2 & 106.24 \(\pm\) 5.30 b & 70.88 \(\pm\) 3.28 a & 142.05 \(\pm\) 13.62 a & 93.97 \(\pm\) 9.62 a \\ \cline{1-1}  & Treat 3 & 107.15 \(\pm\) 8.21 b & 65.49 \(\pm\) 8.92 ab & 118.00 \(\pm\) 10.33 b & 39.49 \(\pm\) 7.33 b \\ \cline{1-1}  & Treat 4 & 130.56 \(\pm\) 4.65 a & 76.77 \(\pm\) 7.03 a & 143.87 \(\pm\) 5.00 a & 45.04 \(\pm\) 10.09 b \\ \cline{1-1}  & Untreat & 106.56 \(\pm\) 7.24 b & 45.79 \(\pm\) 4.70 c & 98.96 \(\pm\) 3.64 b & 48.45 \(\pm\) 5.02 b \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Micro- elements composition at the two sampling date.