# Use of _Chlorella vulgaris_ and _Ulva lactuca_ as Biostimulant on Lettuce
## 3 Results and Discussion
### Chemical Composition  
#### 3.3.1. Algal Chemical Composition  
The results of the chemical analysis of _C. vulgaris_ and _U. lactuca_ (Table 3) show some differences between the two green algae. Firstly, the ash contents were visibly different; _U. lactuca_ had lower water content compared to _C. vulgaris_, this means that the first one is characterized by a higher biomass matter. _C. vulgaris_ fiber content is about 14.5% of the _U. lactuca_ fiber value; the opposite situation was true for the protein content values where _U. lactuca produced_ 37% less than _C. vulgaris_. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & \multicolumn{2}{c}{**Root Length**} & \multicolumn{2}{c}{**Root Weight**} & \multicolumn{2}{c}{**Aerial Part Weight**} & \multicolumn{2}{c}{**Aerial Part Diameter**} & \multicolumn{2}{c}{**FW/DW Ratio** **(Aerial Part)**} \\ \hline Treatment & mm & se & g & se & se & sem & mm & se & \\ \hline control & 14.38  & 0.88 & 22.84  & 1.37 & 776.00  & 39.09 & 20.88  & 0.84 & 24.98 \\ _C. vulgaris_ 15\% & 14.25  & 0.63 & 36.18  & 4.61 & 738.74  & 30.56 & 21.25  & 1.00 & 25,29 \\ _U. lactuca_ 25\% & 15.63  & 1.31 & 24.86  & 2.15 & 624.93  & 40.97 & 19.31  & 0.28 & 24.14 \\ _U. lactuca_ 75\% & 15.38  & 0.92 & 27.16  & 1.45 & 615.45  & 33.03 & 18.50  & 0.25 & 23.61 \\ \hline \end{tabular}
\end{table} 
Table 2: Lettuce morphological analysis after the three treatments. The results are expressed by mean \(\pm\) standard error. In comparison with the control, statistically significant differences are expressed by different letters  
Figure 2: Different root lengths observed in the control and treated plants. Other relevant differences concerned: phosphorus (P) in _U. lactuca_, which was nearly 85% less than in _C. vulgaris_; nitrogen (N) in _U. lactuca_, which was about 63.5% less than in _C. vulgaris_; copper (Cu) in _U. lactuca_, which was about 50% less the other algae; and the fact that around 63% of _C. vulgaris_ manganese (Mn) content was more than in _U. lactuca_. On the other hand, iron (Fe) and magnesium (Mg) in _C. vulgaris_, were, respectively, about 82% and 74% less than in the _U. lactuca_ total content. The difference in calcium (Ca) content between the two algae was about 57% more in _C. vulgaris_; potassium (K) content differed by approximately 48% more in _U. lactuca_. Regarding the other chemical compounds, there were not many differences in values; non-nitrogen extractives content was almost the same in the two kinds of algae. _C. vulgaris_ contains 30% more fats and zinc (Zn) compared to _U. lactuca_. The opposite situation was true for sodium (Na), where the seaweed (_U. lactuca_) contains 30% more Na than the microalgae (_C. vulgaris_). Regarding energy, the analysis showed that _C. vulgaris_ had a 26% higher content than _U. lactuca_. In _C. vulgaris_, the protein content (37.11%) was lower than most of the commercial extracts produced with _Chlorella_ spp. and _Auxenochlorella_ spp. (Chlorophyta) (extract brands: Biotona, Piura, Purasana, Soleil Vie, Alver) as analyzed in [PERSON] et al. [24], where the range of protein content was around 60-66% and also lower than the values of crude protein reported by [PERSON] and [PERSON] [25] (47.82%). For the carbohydrate content, the non-nitrogen extractive reported in this study (51.11%) was between that shown by [PERSON] et al. [24], where the medium range for most of the commercial extracts made with the different _Chlorella_ spp. considered (extract brands: Biotina, Piura, Purasana, Soleil Vie) was around 9.9-14.4%, apart from Alver (extract from _Auxenochlorella prototheoides_) (20.2%) and LG-Chlorella (65.0%), which contained