Genotype and Organ-Specific Variability in Antioxidant Capacities as Well as Polyamine and Osmolyte Levels in Eleven Lisianthus (<i>Eustoma grandiflorum</i> Raf.) Cultivars with Different Flowering Periods

Lisianthus (<i>Eustoma grandiflorum</i> Raf. Shinn.) is a valued plant known for its diverse flower colors and long vase life. Despite considerable research on the physiological roles of osmolytes, polyamines, and phenolic compounds, there is a lack of understanding regarding their specific accumulation patterns across various lisianthus cultivars and organs. This study aims to compare eleven lisianthus cultivars with varying flowering periods according to their accumulation of osmolytes, polyamines, phenolic content, and antioxidant capacities and measure their resistance to abiotic stress factors. High-performance liquid chromatography coupled with fluorescent detection was employed to quantify putrescine (PUT), spermidine (SPD), and spermine (SPM). In addition, proline (PRO), glycine betaine (GB), antioxidant capacities, phenolic content, and flavonoid contents were assessed spectrophotometrically. This comprehensive analysis allowed for a detailed understanding of the biochemical markers. The result indicates a significant genotype and organ-dependent variation in accumulation patterns of inspected metabolites and antioxidant activities. The petals of Rosita Green exhibited the highest levels of phenols and flavonoids, whereas the petals of Rosita Blue Picote demonstrated the highest concentrations of osmolytes. Polyamines were found to be more concentrated in the petals than in the leaves. The average values indicated high levels of polyamines in the Mariachi Carmine (PUT 186.72 nmol g⁻¹ DW) and Mariachi Pink (SPD 227.4 nmol g⁻¹ DW) cultivars. These findings underscore the significance of inspected compounds in stress tolerance among cultivars with different flowering periods, providing insights for optimizing cultivation strategies for lisianthus.