Preharvest silicon nutrition mitigates vibration-induced senescence and extends vase life in cut carnation

Transportation-related mechanical vibration is a major but often overlooked factor reducing the postharvest quality of cut flowers. This study investigated whether preharvest foliar applications of silicon (Si)- and calcium (Ca)-based compounds can mitigate vibration-induced deterioration in cut carnation. Plants were sprayed with potassium silicate, sodium silicate, calcium silicate, nano-silicon, calcium chloride, or calcium nitrate at 100 and 200 mg L⁻¹, and harvested flowers were exposed to simulated road vibration (10 Hz, 10 min). Vase life, relative fresh weight, stem mechanical properties, water relations, oxidative stress markers, pigment content, antioxidant enzyme activities, and leaf nutrient concentrations were evaluated. Simulated vibration significantly reduced vase life, relative water content, pigment pools, and stem mechanical strength, while increasing malondialdehyde accumulation and electrolyte leakage. Foliar application of Si-based compounds markedly alleviated these effects. Under non-stress conditions, potassium silicate at 200 mg L⁻¹ produced the greatest improvements in vase life (by 2.5 days), stem rigidity, antioxidant capacity, and pigment retention. Under vibration stress, nano-silicon at 100 mg L⁻¹ and potassium silicate at 100-200 mg L⁻¹ extended vase life by 2.0-2.8 days, while restoring water balance, limiting oxidative damage, and enhancing phenylalanine ammonia-lyase, peroxidase, and catalase activities. Multivariate analyses (PCA and TOPSIS) consistently ranked potassium silicate and nano-silicon as the most effective treatments. These findings demonstrate that Si nutrition primes coordinated physiological, biochemical, and structural defense mechanisms that enhance the resilience of cut carnations to vibration-induced stress. Preharvest foliar application of potassium silicate or nano-silicon (100 mg L⁻¹) represents a practical and sustainable strategy to improve postharvest quality and extend vase life following transportation.