Combined effects of silica nanoparticles and putrescine on postharvest quality and vase life of ‘Pilaster White’ cut stock (Matthiola incana)

Matthiola incana (stock) is an economically important ornamental species with limited postharvest longevity, which is associated with oxidative damage and deterioration of cellular membranes. This study investigated the effects of preharvest foliar application of silica nanoparticles (SiNPs; 0, 50, 100, and 200 mg L⁻¹) and putrescine (Put; 0, 1.5, and 3 mM), applied individually and in combination, on the postharvest quality and vase life of ‘Pilaster White’ cut stock ( Matthiola incana ). The experiment was conducted under greenhouse conditions using a completely randomized factorial design with three replications. Postharvest assessments included relative fresh weight, relative solution uptake, petal relative water content, electrolyte leakage, malondialdehyde (MDA), total phenolic and flavonoid contents, phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) activities, antioxidant enzyme activities (CAT, APX, GPX, and SOD), and vase life. The combined application of 50 or 100 mg L⁻¹ SiNPs with 1.5 mM Put produced the most favorable overall postharvest responses. These treatments improved water relations, as indicated by greater relative solution uptake and maintenance of petal relative water content, and reduced electrolyte leakage and MDA accumulation compared with the untreated control. They also increased the activities of antioxidant enzymes and PAL, enhanced total phenolic and flavonoid contents, and reduced PPO activity during the postharvest period. Vase life increased from 12.66 days in the untreated control to 25.33 and 25.66 days following the combined application of 50 and 100 mg L⁻¹ SiNPs with 1.5 mM Put, respectively. These physiological and biochemical responses were associated with improved postharvest quality and prolonged vase life. Overall, preharvest foliar application of SiNPs at 50–100 mg L⁻¹ in combination with 1.5 mM Put appears to be a promising approach for extending the vase life of cut stock flowers under the conditions tested.