## 3 Results and Discussion  
Figure 1 shows the number of germinating seeds of Virginia mallow, at the relevant time, in the control sample and relative to the method of seed conditioning (hydro-conditioning alone, and hydro-conditioning in water with biochar added). The germination process in the three samples started at the same time--two days after the seeds were planted. The seeds in the control sample were found to have a germination rate of 22%. Poor germination rates observed in Virginia mallow are associated with the fact that the plant produces hard seeds, with a calcareous coat impervious to water. The impervious layer regulates seed dormancy, as well as the speed at which water penetrates the seeds to reach a sufficient hydration level [34]. \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Material** & **Acid** & **Temperature and Time** & **Power** & **Application Note** \\ \hline Biochar & 7 mL HNO\({}_{3}\) 65\% & - & temperature increase to & & \\  & 1 mL H\({}_{2}\)O\({}_{2}\) 30\% & 200 \({}^{\circ}\)C, time: 15 min; & & \\ Plants & 6 mL HNO\({}_{3}\) 65\% & - & maintaining at temperature & & \\  & 2 mL H\({}_{2}\)O\({}_{2}\) 30\% & & of 200 \({}^{\circ}\)C, time: 15 min & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The parameters of the mineralisation process. Figure 1: Germination rate in Virginia mallow seeds in the control sample, the sample subjected to hydro-conditioning alone, and the sample subjected to hydro-conditioning with biochar added. According to the [PERSON]’s test, the means marked with the same letter are not significantly different at \(\alpha\leq 0.05\) (differences between time germination inside each treatment). The poor germination rate of the control sample could also have been affected by the climatic conditions occurring in the year the plants were harvested, the threshing method used and the duration of storage [35]. The seeds subjected to hydro-conditioning showed a better germination rate than the control sample, reaching 38%. Hydro-conditioning is rather commonly applied in order to improve the ability of hard seeds to germinate. The positive impact of this process on the germination and vigour of crops and garden plants has been reported by numerous researchers. [PERSON] et al. [36] demonstrated the positive effects of hydration as a factor in stimulating growth and metabolic processes in Virginia mallow. The highest metabolic activity was observed in the seeds hydrated to achieve a 35-40% water content, and incubated at 20 \({}^{\circ}\)C for six days. [PERSON] and [PERSON] [37] showed that a pre-sowing hydro-conditioning applied to dill seeds can effectively enhance their viability and stimulate the faster emergence and growth of seedlings. The same authors determined the optimum conditions for hydro-conditioning applied to seedlings of root parsley. Parsley seeds hydrated to a hydration level of 45% and incubated at 20 \({}^{\circ}\)C for three to six days were found to germinate earlier and in larger numbers than non-hydrated seeds. The seedlings emerging from the former developed faster and contained more chlorophyll [38]. Similar findings were reported by [PERSON] et al. [39] who found that seedlings from carrot seeds subjected to hydro-conditioning were faster to emerge and grow compared to the control sample. [PERSON] et al. [40] established that hydro-conditioning is the most effective treatment to improve the germination and vigour of onion seeds. The positive effects of hydration, observed in germination, emergence and plant growth, are associated with metabolic activity, which is more rapidly initiated and increased in seeds before they are planted in soil, and in seedlings at the very beginning of their growth [36]. The addition of processed plant material (biochar from biomass) produced an increase in the number of germinating seeds.