## 9 Influence of Microparticles Treatments on the Synthesis of Plant Metabolites  
It is well known that Ca\({}^{2+}\) controls and modifies plant uptake of Mg\({}^{2+}\) and increases its availability preventing the negative occurrences of metabolic changes on the plant leaves [108]. It has been shown that microspheres loaded with Ca\({}^{2+}\) ions had the most pronounced effect on synthesizing total polyphenols in vine leaves (up to 39%) [163]. Furthermore, it was revealed that treatments with Ca\({}^{2+}\)/Mg\({}^{2+}\) loaded microspheres had a lesser influence on total polyphenols synthesis, signifying the importance of Ca\({}^{2+}\) in synthesizing these compounds. Microspheres treatments on the vine (_Vitis viifera_ L.) have resulted in a significant increase in the antioxidant activity of vine leaves (up to 32%). Ca-alginate microspheres with _T. viride_ spores had the most pronounced effect on antioxidant activity, signifying the synergistic action of chemical and biological agents. Figure 8: Example of copper-alginate microparticles (note the blue color) application during the lettuce seedling planting. It has been revealed that a significant increase in total carotenoids content can be achieved with microspheres treatments. Ca-alginate microspheres loaded with _T. viride_ spores treatment on _Vitis vinifera_ L. leaves resulted in an impressive 62% increase in total carotenoids content, respectively, to the control samples (untreated). Furthermore, Ca-microspheres (without _T. viride_ spores) had significantly influenced vine leaves with a 24% increase in total carotenoids content. It must be noted that with several harvests, the content of biologically active compounds in plants changes. With time, a gradual decrease in carotenoids content in leaves can be seen [168]. Still, after the second harvest, the positive effect on carotenoid retention is significant, with the highest values achieved with Ca-microspheres treatment [163]. During both harvests of vine leaves, significantly highest chlorophyll content (up to 26%, respectively, to the control) was found in vines treated with Ca/Mg-alginate microspheres with _T. viride_ spores [163]. An increase in the number of total chlorophylls in leaves is due to the synergistic action of Ca\({}^{2+}\) and _T. viride_ spores on Mg\({}^{2+}\) uptake during the whole plant growth period. The distribution of Ca\({}^{2+}\) and Mg\({}^{2+}\) in leaves highly depends on the exogenous supply, with the support of _T. viride_. It is known that Ca\({}^{2+}\) influences the uptake of Mg\({}^{2+}\) (an important component of the chlorophyll molecule) [108], and treatment with these microspheres eliminates possible competition between Mg\({}^{2+}\) and Ca\({}^{2+}\), thus increasing the uptake of Mg\({}^{2+}\) by the plants. Increased availability of Mg\({}^{2+}\) for plants prevents the occurrence of chlorosis, necrotic spots on the leaves, and droop, as well as decreases the level of abiotic and biotic stress. It has to be noted that, in this research, no statistically significant change was found in treatments of vine plants on grapes, but somewhat higher values (11%) were observed with Ca/Mg-alginate microspheres (with _T. viride_ spores) treatment [163]. Again, antioxidant activity in treated grapes was found to be non-significant. Even though, an increase of 41% (DPPH) and 25% (ABTS) in antioxidant activity was observed on grapes treated with Ca/Mg-alginate microspheres. Cumulatively, results reveal that Ca\({}^{2+}\) and _T. viride_ do allow better absorption of Mg\({}^{2+}\), stimulating the synthesis of polyphenic compounds in vine leaves. The positive influence of treatments with microparticles is promising in the vine cultivation process and production of higher quality foods. Future research should be focused on treatments with specific agents to achieve higher stimulation in grapes. [PERSON] et al.