Importantly, nitric oxide (NO) serves as a secondary messenger of ABA to enhance salt tolerance by increasing the K+/Na+ ratio (León et al., 2014). It has been indicated that plants seem to own the priming-like mechanisms that memorize the foregoing NO exposure events and activate defensive responses following harmful conditions (Tanou et al., 2009). Zhang et al. (2009) have reported that transgenic tobacco plants with high ABA levels are more tolerant to the controls under salt stress, which is closely associated with the ABA-induced NO accumulation. NO exposure markedly increases the tolerance of plants to Fe deficient conditions by efficient mobilization of cell wall Fe and activation of Fe deficiency-induced transcription factor 1 (FIT1) that regulates Fe uptake in plants (Graziano and Lamattina, 2007; Chen et al., 2010; Wang et al., 2017). Thus, plants with high level of ABA may possess more efficient systems to acquire Fe and detoxify Na+ for resisting the saline–alkaline stress.