The Effect of Cerium Nitrate and Salicylic Acid on Vase Life and Antioxidant System of Cut Lisianthus (Eustoma grandiflorum cv. Pink Picotte) Flowers

To reduce the postharvest loss of cut lisianthus ‘Pink Picotte’ flowers, an experiment was conducted based on a randomized complete design with three replications. The experimental treatments were composed of salicylic acid (SA) at three rates of 50, 100 and 200 mg L-1 and cerium nitrate (Ce(NO3)3) at four rates of 20, 40, 80 and 200 μM and distilled water (control) applied at 24-h pulses with 3% sucrose. It was found that SA and Ce (NO3)3 influenced all recorded traits significantly except for dry matter. The treatments of 40 μM Ce (NO3)3 and 100 mg L-1 SA performed the best in extending vase life so that they were associated with the longest vase lives of 15.42 and 15.20 days, respectively. In addition to improving vase life, these two treatments outperformed the other treatments in inhibiting the loss of fresh weight, reducing bacterial colony in vase solution, and increasing leaf chlorophyll. The highest catalase activity (8.57 IU g-1 FW min-1) was observed in the plants treated with 40 μM Ce (NO3)3, not differing from the treatments of 50 and 100 mg L-1 SA significantly. Furthermore, these treatments were effective in increasing superoxide dismutase activity. The results revealed that the application of 200 mg L-1 SA had adverse impacts on the vase life and the related traits. Overall, it is not recommended to apply high concentrations of Ce (NO3)3 (80 and 200 μM) and SA (200 mg L-1) in the vase solution of cut lisianthus ‘Pink Picotte’ flowers.