Synthesis, Characterization, and Effect of Succinic Acid-FeSO₄·7H₂O Complex on in vitro Shoot Initiation of VSL-2 Plants

In vitro micropropagation is a cornerstone of modern plant biotechnology, enabling rapid production of genetically uniform and pathogen-free plants. Iron (Fe) plays a critical role in plant growth and development, yet its availability in standard Murashige & Skoog (MS) media can be limited. This study synthesized a succinic acid-FeSO₄·7H₂O complex and evaluated its structural, thermal, and biological properties in relation to shoot initiation of the VSL-2 plant line. FT-IR and thermogravimetric analyses confirmed the monodentate coordination of succinate to Fe (II) and the thermal stability of the complex up to ~200°C. Application of the complex in MS medium significantly improved shoot initiation in a concentration-dependent manner, with the optimal effect observed at 1.5 mg·100 mL⁻¹, increasing initiation success to ~90% and the average number of new plantlets to 4.0 per explant. The stimulatory effect is likely due to enhanced Fe bioavailability, coupled with succinate-mediated modulation of antioxidant enzyme activity and redox balance, supporting meristematic activity. These findings suggest that succinate-bound Fe is a stable and effective alternative to conventional Fe sources, providing controlled Fe delivery and promoting early morphogenic events in plant tissue culture. The results have potential implications for improving micropropagation efficiency across diverse plant species.