Objective Using three Oncidium hybridum cut flower cultivars 'Sweet sugar', 'Lemon heart', and 'Gower ramsey' as test materials, this study compared their ornamental quality and senescence characteristics during vase life, screened the best-performing cultivar, and further investigated the effects of different preservative formulations on vase longevity and quality. The research provides a basis for cut flower preservation of O. hybrids.

Method Vase-life experiments were conducted to determine senescence progression, vase life, fresh weight change, water uptake, bud and floret opening rate, and floret abscission rate of the three cultivars. Based on the comparative results, the optimal cultivar 'Lemon heart' was selected for further experiments with four vase solutions: control (deionized water), 5.0 mg/L nanosilver (NS) + 5% sucrose, 0.05 mmol/Lsilver thiosulfate (STS) + 5% sucrose, and 5.0 mg/L NS + 0.05 mmol/L STS + 5% sucrose. The effects of these treatments on vase-life performance and ornamental traits were evaluated.

Result Significant differences were observed among the three cultivars in vase life, senescence progression, and water balance. 'Lemon heart' exhibited the longest vase life (18.4 d), significantly exceeding 'Sweet sugar' (14.2 d) and 'Gower ramsey' (12.6 d). It also showed the highest fresh weight change rate, water uptake, and floret opening rate, along with the lowest bud abscission rate. 'Gower ramsey' showed the earliest wilting and senescence symptoms: mild floret shrinkage appeared on the 6 d of vase holding, and the floret abscission rate reached 45.5% by the 16 d of vase holding, resulting in the shortest vase life among the three cultivars. In preservative screening for 'Lemon heart', the treatment with 5.0 mg/L NS + 5% sucrose demonstrated the best efficacy, achieving a vase life of 27.8 d, significantly longer than the control (18.4 d), 0.05 mmol/L STS + 5% sucrose (19.6 d), and 5.0 mg/L NS + 0.05 mmol/L STS + 5% sucrose (20.4 d). Additionally, this treatment was significantly superior to the other treatments in improving ornamental quality, maintaining fresh weight (the relative fresh weight change rate remained above 95% on the 21 d of vase holding), enhancing water uptake, and reducing floret abscission rate (the abscission rate was only 15.3% on the 24 d of vase holding).

Conclusion Among the three Oncidium cut flower cultivars, 'Lemon heart' demonstrated the optimal vase performance. The formulation of 5.0 mg/L NS +5% sucrose serves as an effective preservative, significantly extending vase life and maintaining high ornamental quality.