Ascorbic Acid Increases Cut Flower Longevity of Sword Lily by Regulating Oxidative Stress and Reducing Microbial Load

The longevity of cut flowers is associated with various physio-biochemical traits. To extend vase life (VL) of cut flowers, a wide range of chemical-based preservatives solutions have been used, which raise the concerns of human health and environmental pollution. This study explored the potential of using ascorbic acid (AsA) to naturally extend the VL of cut sword lily (Gladiolus grandifloras) ‘White Prosperity’ flowers. Fresh spikes were placed in vase solutions containing 1, 2, 3 and 4% AsA solutions, denoted as AsA1, AsA2, AsA3 and AsA4, respectively, as well as distilled water (DsW) as control. The AsA solutions prolonged the VL from 5.75 to 12.5 days. The treatment AsA4 significantly improved the relative fresh weight, floret diameter, the number of open florets, and chlorophyll contents. Ascorbic acid decreased oxidative stress (malondialdehyde and hydrogen peroxide) and boosted proline and total soluble proteins levels in cut sword lily, indicating a link with reduced water stress. AsA application improved phenols and sugars in the florets. Bacterial count was low in AsA-based vase solutions. Overall, AsA4 had the best performance with respect to VL and other associated traits. Given the encouraging outcomes of the ongoing research, AsA may be recommended as a viable postharvest treatment to extend the VL of sword lily.