Salicylic acid modulates cutting-induced physiological and biochemical responses to delay senescence in two gerbera cultivars

The postharvest longevity of gerbera (Gerbera jamesonii) flowers has a critical importance in determining their commercial value; and therefore, there is a commercial demand for prolonging their vase life (VL). Here, we tested the efficacy of salicylic acid (SA, 150 mu M) preservative in extending longevity of cut flower of two gerbera cultivars, namely the Sunway' and Bayadere', of which water-held Bayadere' has longer VL than water-held Sunway'. The results indicated that exogenous SA could significantly prolong the VL of cut flowers of both Sunway' and Bayadere' cultivars, with better preservative effect being observed on Sunway'. SA preservative was more effective in ameliorating relative water uptake and relative fresh weight in Sunway' than in Bayadere', which was accompanied by a greater decrease in proline accumulation. Application of SA prolonged the VL of two cut gerbera flower cultivars by inhibiting the activity of polyphenol oxidase involved in browning reaction, and decreasing oxidative stress through improving reactive oxygen species-scavenging antioxidant capacity, which included accumulation of total phenolic compounds and total flavonoids, and enhancement of enzymatic antioxidant activities. As a result, membrane lipid peroxidation levels were reduced in cut flowers of both cultivars, with higher reduction level being observed in Sunway' than in Bayadere'. Additionally, SA preservative was more efficient in maintaining a greater content of total soluble proteins in Sunway' than in Bayadere'. These findings clearly demonstrated that SA has higher preservative effects on extending VL of Sunway' than that of Bayadere'. Taken together, SA can be recommended to farmers for postharvest treatments to maintain quality and delay senescence of gerbera flowers.