## 3 Results
### Biochemical Traits  
Biochemical traits, namely carbon, nitrogen, sucrose, and starch content, showed different responses in leaves, seeds, and root tissues in the four experimental treatments considered in the study (Figures 5 and 6, Tables 5 and 6). With increasing temperatures, the percentage of carbon and nitrogen significantly decreased within the leaves (Figure 5a,b and Table 5).  
Figure 5: The effect of increasing temperature and CO\({}_{2}\) enrichment on carbon (% DW) (left column) and nitrogen (% DW) (right column) content on leaves (**a**,**b**), seeds (**c**,**d**), and roots (**e**,**f**) in seedlings of _Enhalus acoroides_ at the end of the experimental period. Values are mean \(\pm\) SE (n = 6).  
Figure 6: The effect of increasing temperature and CO\({}_{2}\) enrichment on sucrose (left column) and starch (right column) content (sucrose equivalents g\({}^{-1}\) DW) on leaves (**a,b**) and seeds (**c,d**) in seedlings of _Enhulus acoroides_ at the end of the experimental period. Values are mean \(\pm\) SE (n = 3 for leaves and n = 6 for seeds).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Dependent Variable** & **Factor** & **TSS** & **F-Value** & \(p\)**-Value** \\ \hline \multicolumn{5}{c}{**Leaves**} \\ \hline Carbon content & **Temperature** & **21.045** & **14.638** & **0.001** \\  & CO\({}_{2}\) & 1.168 & 0.812 & 0.379 \\  & Interaction & 0.390 & 0.271 & 0.609 \\ \hline Nitrogen content & **Temperature** & **0.507** & **24.300** & **<0.001** \\  & CO\({}_{2}\) & 0.028 & 1.333 & 0.263 \\  & Interaction & 0.006 & 0.276 & 0.605 \\ \hline Seeds & & & & \\ \hline Carbon content & Temperature & 8.339 & 0.248 & 0.624 \\  & CO\({}_{2}\) & 2.916 & 0.087 & 0.771 \\  & Interaction & 82.470 & 2.454 & 0.133 \\ \hline Nitrogen content & Temperature & 0.010 & 0.215 & 0.648 \\  & CO\({}_{2}\) & 0.026 & 0.577 & 0.456 \\  & Interaction & 0.019 & 0.416 & 0.526 \\ \hline Roots & & & & \\ \hline Carbon content & Temperature & 3.192 & 0.379 & 0.545 \\  & CO\({}_{2}\) & 0.009 & 0.001 & 0.974 \\  & **Interaction** & **37.233** & **4.425** & **0.049** \\ \hline Nitrogen content & Temperature & 0.016 & 1.027 & 0.324 \\  & CO\({}_{2}\) & 0.023 & 1.436 & 0.245 \\  & Interaction & 0.016 & 1.031 & 0.323 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Results of analysis of variance (two-way ANOVA test) on the effects of temperature and CO\({}_{2}\) on the carbon and nitrogen content of the leaf, seed, and root tissue (Figure 5). \(p\)-Values in bold are statistically significant (<0.05) (TSS: Total sum of squares).  
In contrast, there were no significant differences in single factor effects of temperature or CO\({}_{2}\) in the carbon and nitrogen content within the seeds (Figure 5c,d and Table 5) or in the roots (Figure 5e,f and Table 5). However, there was an interactive effect between temperature regimes and CO\({}_{2}\) concentration in the carbon content in the root tissue, which showed the highest concentrations in the 31 \({}^{\circ}\)C-ambient CO\({}_{2}\) and 27 \({}^{\circ}\)C-enriched CO\({}_{2}\) treatments (Figure 5e and Table 5).  
Leaf sucrose and starch concentrations were generally higher in enriched CO\({}_{2}\) treatments (Figure 6a,b and Table 6). However, these differences were not statistically significant. There was an interaction effect on starch concentrations in the leaves (\(p\)-value = 0.07), which was especially high in the 31 \({}^{\circ}\)C-enriched CO\({}_{2}\) treatment. In contrast to carbon or nitrogen content, sucrose concentrations significantly responded to an increasing temperature on seed tissues, which are less used in regimes of 31 \({}^{\circ}\)C (Figure 6c and Table 6). The highest concentrations of sucrose in the seeds were found in the 31 \({}^{\circ}\)C-ambient CO\({}_{2}\) treatment, whereas the highest starch concentration in the seeds was found in the 31 \({}^{\circ}\)C-enriched CO\({}_{2}\) treatment, even though differences were not significant (Figure 6c,d and Table 6).