stress, plants have evolved different response mechanisms to deal with salt stress, such as salt tolerance, avoidance and escape, and recovery mechanism [4; 5]. The SOS pathway plays a key role in regulating cellular ion homeostasis during salt stress and represents the well conserved salt tolerant mechanism in higher plants [3; 6; 7]. Plant hormones are another crucial regulator for plant growth in response to salt stress, among which ABA functions as a central integrator for developmental process and abiotic tolerance, including salt tolerance [8; 9]. ABA plays a major and irreplaceable role during salt stress response in plants by regulating ion homeostasis, biosynthesis of osmolytes, ROS (reactive oxygen species) scavenging and salt-responsive gene expression. Application of exogenous ABA will impair the harmful effect of salt stress [10]. However, the content of ABA which is well known as a key repressor of seed germination [11] is increased by salt stress during seed germination [12]. Germination of an ABA biosynthesis defective mutants, such as _aba2_, was faster than that of WT under salt stress [12; 13], suggesting that elevated ABA functions negatively in salt tolerance during seed germination. Nitric oxide (NO) is a gaseous, free-radical and redox-signaling molecule which has multiple functions and acts as molecular messenger during plant growth and development. NO also plays important roles in response to different stresses, including drought stress, temperature stress, salt stress and heavy metal stress [14; 15; 16; 17]. In plants, there are several origins for NO production, among which the nitrate reductase (NR) pathway is the best-characterized and most important pathway for NO production [18]. Double mutation of two NR encoding genes, _nia1/nia2_, resulted in reduced content of both NO and nitrite in _Arabidopsis_[19]. Numerous studies have proved that NO is critical in promoting salt tolerance of plant at different developmental stage [20; 21]. In salt-affected plants, NO was found to significantly improve seed vigor and germination [22], while priming or pretreatment with SNP, a donor of NO, will significantly promote seed germination and early seedling growth under salt stress [23; 24]. It has been well proved that NO play versatile roles in promoting salt tolerance, including maintaining ion homeostasis by enhancing K\({}^{+}\) uptake [25], promoting antioxidant defenses and osmolytes biosynthesis and/or accumulation against to salinity-induced oxidative stress and osmotic stress, respectively [26; 27], interacting with other signaling pathways in response to salt stress [28; 29]. During seed germination, the accumulation of NO at early stage of germination resulted in degradation of ABA, which was blocked in _cyp707a2_ mutant, a key gene for ABA catabolism [30]. Seed germination was inhibited in NR defective mutant, _nia1/nia2_[19], suggesting the importance of NR-associated NO during seed germination. However, it is still unclear whether the NR-associated NO also plays a role in response to salt stress during seed germination in rice. Seed germination is a key developmental stage during the life cycle and is tightly controlled in plants [31; 32]. Antagonistic interaction between ABA and GA (gibberellin) plays a crucial role in regulating seed germination [33]. During the early stage of seed germination, ABA catabolism was activated, which thus release the inhibiting effect on seed germination in rice. It has been demonstrated that nitrate was also involved in breaking seed dormancy and promoting seed germination independently of its reduction into NO by NR in _Arabidopsis_[34]. Recently, NIN-like protein (NLP8), a nitrate-activated transcription factor, was identified to activate the expression of _CYP707A2_, an ABA catabolism gene in _Arabidopsis_, and thus was essential for nitrate-promoted seed germination [35], suggesting that nitrate itself might act as a molecular signal to promote seed germination independent on NR-associated NO production.