Efficacy of ABA-Mimicking Ligands in Controlling Water Loss and Maintaining Antioxidative Capacity of Spinacia oleracea

Abscisic acid (ABA) is a central regulator for various developmental processes and responses to abiotic stresses in plants. However, its practical application in controlling water loss of postharvest produces is largely restrained. Herein, the present study reported that two ABA-mimicking ligands, AM1 and AMF4, markedly reduced water loss by promoting stomatal closure and effectively alleviated weight loss in spinach. AM1 and AMF4 also alleviated chlorophyll and vitamin C degradation and simultaneously reduced hydrogen peroxide and malondialdehyde (MDA) production; moreover, both enzymatic and nonenzymatic systems involved in antioxidative capacity were activated. The expression levels of SoOST1, SoSLAC1, SoRCAR3, SoPYL5, SoNCED3, and SoAREB1 were also up-regulated. These findings indicate that AM1 and AMF4 are promising as novel means for reducing water loss, maintaining visual quality, delaying senescence, and extending shelf life in leafy vegetables.