Exogenous Nitric Oxide Pretreatment Enhances Chilling Tolerance of Anthurium

Abstract

Nitric oxide (NO) is well known for its multifaceted physiological roles as a signaling molecule in plants. Previous studies have indicated that exogenous application of NO may be useful for alleviating chilling injury (CI) in fruits and vegetables. However, the potential role and mechanism of NO in mitigating chilling stress in anthurium (Anthurium andraeanum) remain unclear. In this study, physiological and biochemical analysis were performed to investigate the effects of exogenous NO in alleviating CI in anthurium. Anthurium seedling plants were treated with the NO donor sodium nitroprusside (SNP) at four concentrations (0, 0.2, 0.4, and 0.8 mm) and stored at 12/5 °C (day/night) for 15 day. The results showed that exogenous SNP mitigated the adverse effects of chilling on anthurium, and the most effective concentration was 0.2 mm. In addition, NO effectively improved the CI index, malondialdehyde (MDA) content, electrolyte leakage, photochemical efficiency (Fv/Fm), and chlorophyll loss of anthurium during low temperatures. Pretreatment with SNP also increased the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX); the content of antioxidants including glutathione (GSH), ascorbic acid (AsA), and phenolics; and reduced the accumulation of hydrogen peroxide and O2−. SNP pretreatment at 0.2 mm also significantly promoted the accumulation of proline, increased the activity of Δ1-pyrroline-5-carboxylate synthetase (P5CS), and reduced the activity of proline dehydrogenase (PDH), when compared with control (0 mm SNP→Chilling) under chilling stress. These results indicated that NO could enhance the chilling tolerance of anthurium by elicitation of an antioxidant response and proline accumulation for maintaining cell membrane integrity.