## 3 Results
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Treatments**} \\ \hline
**Metabolites [mM]** & **C** & **FB** & **EB** \\ \hline Citric acid & 0.800 \(\pm\) 0.286 & 0.440 \(\pm\) 0.149 & 0.953 \(\pm\) 0.334 \\ Formic acid & 8.283 \(\pm\) 0.707 a & 5.777 \(\pm\) 0.656 a & 14.490 \(\pm\) 1.643 b \\ Malic acid & 2.380 \(\pm\) 0.882 & 0.970 \(\pm\) 0.216 & 2.680 \(\pm\) 1.097 \\ Alanine & 0.960 \(\pm\) 0.182 & 0.620 \(\pm\) 0.029 & 0.910 \(\pm\) 0.208 \\ Argin & 8.533 \(\pm\) 0.757 & 7.980 \(\pm\) 0.723 & 8.220 \(\pm\) 0.730 \\ Asparagine & 19.850 \(\pm\) 2.158 a & 36.583 \(\pm\) 3.704 b & 43.107 \(\pm\) 6.709 b \\ Glutamine & 3.847 \(\pm\) 1.178 & 6.020 \(\pm\) 1.075 & 6.017 \(\pm\) 1.021 \\ Isoleucine & 0.167 \(\pm\) 0.009 b & 0.107 \(\pm\) 0.012 a & 0.187 \(\pm\) 0.017 b \\ Leucine & 0.180 \(\pm\) 0.021 & 0.137 \(\pm\) 0.012 & 0.197 \(\pm\) 0.041 \\ Phenylalanine & 0.203 \(\pm\) 0.032 & 0.163 \(\pm\) 0.026 & 0.257 \(\pm\) 0.048 \\ Threonine & 0.510 \(\pm\) 0.021 b & 0.467 \(\pm\) 0.033 a & 0.593 \(\pm\) 0.064 b \\ Tryptophan & 0.387 \(\pm\) 0.044 & 0.323 \(\pm\) 0.074 & 0.443 \(\pm\) 0.050 \\ Tyrosine & 0.133 \(\pm\) 0.009 & 0.083 \(\pm\) 0.019 & 0.133 \(\pm\) 0.034 \\ Valine & 0.220 \(\pm\) 0.012 a & 0.197 \(\pm\) 0.017 a & 0.313 \(\pm\) 0.052 b \\ Frutose & 2.783 \(\pm\) 0.752 a & 2.993 \(\pm\) 0.908 a & 8.000 \(\pm\) 1.631 b \\ Glucose & 2.040 \(\pm\) 0.517 a & 3.040 \(\pm\) 0.364 a & 5.687 \(\pm\) 1.310 b \\ Myo-inositol & 0.277 \(\pm\) 0.078 & 0.410 \(\pm\) 0.191 & 0.650 \(\pm\) 0.120 \\ Sucrose & 1.847 \(\pm\) 0.247 b & 2.163 \(\pm\) 0.353 b & 0.473 \(\pm\) 0.046 a \\ UDP glucose & 0.033 \(\pm\) 0.003 & 0.037 \(\pm\) 0.003 & 0.030 \(\pm\) 0.006 \\ Betaine & 0.680 \(\pm\) 0.095 & 0.433 \(\pm\) 0.071 & 0.540 \(\pm\) 0.117 \\ Choline & 0.670 \(\pm\) 0.110 & 0.470 \(\pm\) 0.062 & 0.697 \(\pm\) 0.162 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Primary metabolites from sweet potato leaves after 3 days of treatment application. Data are shown as concentrations in 50 mg of sample. Data are expressed as means \(\pm\) SE. Different letters refers to statistical differences calculated with ANOVA and Duncan test as a post hoc test (\(p<0.05\)). Figure 2: Analysis of pigments in _I.__hattas_ leaves of the different treatments (C, control; FB, free boron; EB, encapsulated boron). Data are represented as means and SE errors. No statistical differences were observed (n.s.). As for the sugars (Table 2), glucose, fructose, and myo-inositol were significantly higher only in plants treated with encapsulated B. However, when sucrose was determined, the opposite effect was observed. In this case, a significant decrease appeared in encapsulated B treated plants. As for the concentration of UDP-glucose, no significant differences were observed. Similarly, the metabolites betaine and choline appeared in low concentrations, but no changes in their concentrations were observed after the application of the treatments. Phylogenetic analyses (Figure 3) revealed an almost pair-to-pair homology between protein sequences of the two _Ipomoea_ species (_I. triloba_ and _I. nil_) used as templates to design primers in order to analyze the expression of the NIP aquaporin family in _Ipomoea_ _battas_. The NIP family presents a high homology between species, being more evident within the _I. nil_, _I. triloba_, and _A. thaliana_ species whose protein sequences cluster in the same clades in almost all NIPs isoforms. On the contrary, as was expected, the two cereal species _Z. mays_ and _O. sativa_ showed a high homology between their isoforms. As revealed by the phylogenetic tree (Figure 3), NIPs aquaporins of _Ipomoea_ species are divided into seven groups from NIP1 to NIP7, except NIP3, which only appeared in _I. triloba_ plants. The relative expression of genes related to B uptake, such as NIP aquaporins and BOR transporters genes, (Figure 4) revealed a general increase of those in plant leaves treated with nanoencapsulated B.