Genetic Stability and Photosystem II Functioning of In Vitro-Recovered Lamprocapnos spectabilis (L.) Fukuhara After ZnO + Ag Nanoparticles or Melatonin Exposure During Vitrification—Preliminary Study

The success of plant tissue cryopreservation strongly depends on maximizing explant survival during storage in liquid nitrogen and recovery, which requires species-specific protocol optimization and ongoing refinement. This study examined the effect of Plant Vitrification Solution 3 (PVS3) supplemented with nanoparticles (NPs) or melatonin (MEL) on the recovery of <i>Lamprocapnos spectabilis</i> (L.) Fukuhara explants after cryostorage. Treatments with ZnO + Ag NPs, as well as different MEL concentrations, were applied to evaluate their influence on explant survival, photosynthetic efficiency, and genetic stability. The highest recovery (40-44%) was obtained with PVS3 containing 50 mg L^-1 ZnO + 0.1% Ag NPs and PVS3 supplemented with 8 mg L^-1 MEL, which was 17.5-20% higher than in the control. These treatments, however, did not ensure the highest photosynthetic efficiency of recovered plants. PVS additives likely support recovery by slowing metabolism and reducing oxidative stress, with lower photosynthetic activity suggesting a lag phase in plastid regeneration. Using the Start Codon Targeted (SCoT) marker system, no significant genetic alterations were detected in recovered plants of any tested variant. These findings demonstrate the feasibility of optimizing cryopreservation protocols for <i>L. spectabilis</i> and encourage further research on combined NPs and MEL treatments or alternative nanocarriers.