Effects of nitric oxide and nitrogen on seedling emergence, ion accumulation, and seedling growth under salinity in the euhalophyte Suaeda salsa

Recently nitric oxide (NO) has emerged as a key signal molecule in plants. However, little is known about the role of NO in the salt tolerance of halophytes. Effects of the NO donors sodium nitroprusside (SNP) and nitrate (NO3-) on growth and ion accumulation in the euhalophyte Suaeda salsa under salinity were investigated in the present study. The results showed that higher SNP supply increased seedling emergence, but SNP had no effect on shoot growth and the concentrations of Na+, K+, Cl-, and NO3-. Higher NO3- had no effect on seedling emergence of the species. Shoot Cl- decreased, but NO3- increased markedly, with a higher NO3- supply. The decrease in the estimated contribution of Cl- to the osmotic potential was compensated for by an increase in that of NO3-. It appears that NO3- plays an important osmotic role in S. salsa under high salinity with a higher NO3- supply, and this trait may increase salt tolerance of the species under high salinity.