## 4 Discussion  
The synthesis of metallic nanoparticles has garnered significant interest due to its diverse applications ranging from medicine to catalysis and the electronics industry. Traditionally, nanoparticle synthesis methods employ chemical reagents and organic solvents that are harmful to the environment and costly to manage. These methods often require rigorous reaction conditions such as high temperatures and pressures to produce nanoparticles with controlled size and shape. In contrast, green methods, such as the one employed in this study, utilize plant extracts containing a variety of bioactive compounds like polyphenols, flavonoids, and terpenoids, which act as natural reducers and stabilizers of nanoparticles [16]. These biological extracts offer several advantages over traditional methods, including cost reduction, process simplicity, and the ability to produce nanoparticles with superior properties such as enhanced colloidal stability and potential biocompatible applications. Figure 6: FTIR spectra of (blue) cork oak somatic embryos aqueous extract and (red) NPs. Using somatic embryos as a source of plant material can be likened to having a biofactory of secondary metabolites under controlled conditions. This approach offers distinct advantages compared to other plant extracts, as somatic embryos provide a consistent and reproducible supply of bioactive compounds. Unlike natural plant sources that can vary in chemical composition due to environmental factors, somatic embryos can be cultivated under controlled conditions, ensuring the production of metabolites in a predictable manner [25]. This controlled environment not only enhances the yield and quality of secondary metabolites but also facilitates the standardization of experimental conditions [26], making somatic embryos an ideal choice for applications requiring reliable and consistent biochemical profiles. The characterization of this plant extract from in vitro-derived _Q. suber_ somatic embryos, using UV-visible spectroscopy, revealed several significant absorbance peaks in the range from 265 to 340 nm, with specific maxima at 265, 283, 300, and 310 nm. These peaks are indicative of the presence of phenolic compounds and flavonoids (flavanones, flavanones, and isoflav), as described by [PERSON] [27]. Phenolic compounds and flavonoids are well-known for their antioxidant properties and their ability to act as reducing agents in the formation of metallic nanoparticles [28]. Other plant materials similar to somatic embryos, such as plant callus cultures, have proven equally promising in the green synthesis of nanoparticles (NPs). Callus cultures are capable of producing a wide range of bioactive compounds that facilitate the reduction and stabilization of metallic NPs [29]. Nevertheless, phytates, ubiquitous in plant tissues, pose a challenge for direct spectrophotometric analysis due to their lack of specific absorption spectra, necessitating the use of indirect methods such as the molybdate blue method for detection in extracts. Phytic acid, also known as inositol hexophosphate or IP6, is a compound present in plants. It serves as the principal form of phosphorus storage, especially in seeds. For example, acoms of oak species exhibit significant amounts of phosphorus, although it is possible to discern species-specific distribution patterns [30]. Furthermore, phosphorus concentrations vary significantly across seed parts, notably six times lower in the pericarp and testa compared to embryos. Our study determined a substantial phosphate content of 23.6 \(\upmu\)Mol PO\({}_{4}\)\({}^{3-}\)/mg DW (equivalent to 2.24 mg/g in embryo tissue) in extracts from cork oak somatic embryos. This is much higher compared to _Quercus robur_, where phosphorus content in embryos typically ranges from 1.18 to 0.75 mg/g [31]. Probably, the species _Q. suber_ and the use of somatic embryos, which lack outer coverings, may influence the high quantities of phytates in the extract.