Apart from NO, abscisic acid (ABA) and hydrogen peroxide (H2O2) are also signals for plant responses to various environmental stresses (Desikan et al., 2004; Miller et al., 2008; Hancock et al., 2011). Water stress induces accumulation of ABA and H2O2, which mediates nitric oxide (NO) generation and, in turn, activates mitogen-activated protein kinase (MAPK) cascades and eventually