# S seaweed Polysaccharides in Agriculture: A Next Step towards Sustainability
## 4 Current and Future Perspectives
### Future Perspectives  
There is still a lack of knowledge of what specific bioactive compounds from seaweed have an impact on plant metabolism and growth.  
Although there is an increased number of studies regarding the use of seaweed extracts or seaweed biomass in agricultural crops, very few are focused on the impact of seaweed  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Seaweed/Source** & **Polymer** & **Plant Species** & **Application Method** & **Bioactivity** & **Reference** \\ \hline \hline \multirow{8}{*}{_Schizophrenia binder_} & \multirow{8}{*}{Oligo-Carrageenanns (Poly-Ga)} & \multirow{8}{*}{_Nicotiana tabacum L._} & \multirow{8}{*}{Folar spray} & \multicolumn{1}{c}{Stimulates growth and induces} & \multirow{8}{*}{[12]} \\  & & & & defense in tobacco plants by activating the antioxidant & \\  & & & & enzyme AP, which modulates the level of the antioxidant & \\  & & & & compounds ASC and DHA. The & \\  & & & & activation of the defense & \\  & & & & enzyme PAL leads to the & \\  & & & & activation of the & \\  & & & & phenylpropanol pathway and & \\  & & & & to the synthesis of secondary & \\  & & & & metabolites with antiviral & \\  & & & & activity. & \\ \hline \hline \multirow{8}{*}{_Tichacarpus crinitus_} & \multirow{8}{*}{\(\kappa/\beta\)-carrageenanan} & \multirow{8}{*}{_Nicotiana tabacum L._} & \multirow{8}{*}{Leaf infiltration} & Resistance to TMV in tobacco plants by interfering with the deproteinization and replication in the cells of binding virions, leading to fewer necrotic lesions on the leaves. & \multirow{8}{*}{[69]} \\  & & & & leading to fewer necrotic lesions on the leaves. & \\ \hline \hline \multirow{8}{*}{_Tichacarpus crinitus_} & \multirow{8}{*}{\(\kappa/\beta\)-carrageenanan} & \multirow{8}{*}{_Datura stramonium L._} & \multirow{8}{*}{Leaf infiltration} & Inhibits the development of the potato virus X (PVX) infection in _D. strumonium._ & \multirow{8}{*}{[70]} \\  & & & & & in \\ \hline \hline \end{tabular}
\end{table}
Table 2: _Cont._polysaccharides. These compounds take up most of all the seaweed biomass and are reported to show valuable results in the protection against plant pathogens.  
In the studies regarding the effects of seaweed polysaccharides in crops, many lack an explanation of the polysaccharide extraction process. Furthermore, most of the studies tend to rely more on traditional extraction methods without optimizations and greener protocols. Moreover, the majority were executed in in vitro assays exclusively, without further extension to in vivo assays, such as pot experiments, green house experiments, or in soil experiments, depending on the crop. Nonetheless, in the experiments carried out in the field, many studies [45; 56; 57; 58; 63; 64; 65; 66; 68] did not grant information about the composition of the soil or substrates where plants were grown, as well as the biochemical composition of the plants after the experiment and a correlation between what the soil absorbed vs what the plant absorbed after the extracts were applied.  
This could also be an interesting topic to focus on in the future; seaweed extracts could potentially improve soil quality, aid the soil recovery, and elevate the soil remediation.  
As was said previously, there are many studies (Tables 1 and 2) in which seaweed polysaccharides exhibit protection against plant pathogens. Therefore, it would be beneficial to test their impact on plant growth and chemical composition.  
The next step in sustainable agriculture is to understand the mechanisms of action of specific bioactive compounds and form a correlation with their molecular weight.