Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions

Abstract

Summary• The effects of salinity and nitrogen (N) on growth and the role of NO 3 -in osmotic adjustment in the leaf-succulent euhalophyte Suaeda physophora and the stemsucculent xerophyte Haloxylon persicum were evaluated.• Seedlings were exposed to 1 or 300 m M NaCl in 0.05, 1 or 10 m M NO 3 --N treatments for 24 d.• At 10 m M NO 3 -, 300 m M NaCl had no adverse effect on the concentration of NO 3 -, the content of organic N, and the estimated contribution of NO 3 -to osmotic potential in leaves of S. physophora , but markedly reduced these in stems of H. persicum . At 300 m M NaCl, more NO 3 -but less Cl -and Na + were involved in osmotic adjustment in leaves of S. physophora compared with that in stems of H. persicum . The contribution of NO 3 -to osmotic potential was much higher in S. physophora , but lower in H. persicum , than that of amino acids at 300 m M NaCl.• The nutritional and osmotic roles of NO 3 --N seem to be more important in the euhalophyte S. physophora than in the xerophyte H. persicum under saline conditions. These characteristics may determine the natural distributions of the two species in saline or arid environments.

Mitigating effect of salicylic acid and nitrate on water relations and osmotic adjustment in maize, cv. Lluteño exposed to salinity

“…The consequence of this water loss is a lower RWC. SA and NO 3 -revert these adverse effects of salinity, possibly by means of an osmotic regulation at the level of the leaf and root (Song et al, 2006). This reversion of the RWC appears to indicate that these mitigating agents favor the entrance of water in the roots and/or avoid water loss by the roots (Carvajal et al, 1999;Hasegawa et al, 2000;Zhu, 2001;Martinez-Ballesta et al, 2006;Burgess and Bleby, 2006).…”

“…It is known that SA with NO 3 -reduces Ψ w (Song et al, 2006, Szepesi et al, 2009. The magnitude of this reduction will depend on how they are applied, their concentrations, and the plant species (Hayat et al, 2008).…”

“…NO 3 -has been considered an osmotic regulator due to its ability to replace other solutes, especially in halophytic plants (Veen and Kleinendorst, 1986;Song et al, 2006). If NO 3 -is an osmotic regulator, it will diminish the negative effects caused by the entrance of NaCl and will facilitate water transport by the roots, increasing water absorption as well as providing a nutritional effect (McIntyre et al, 1996;Song et al, 2006). It is interesting to note that in halophytic plants a greater salt concentration induces the expression of aquaporin genes, allowing water to enter the plant (Qi et al, 2009).…”

Succinic Semialdehyde Promotes Prosurvival Capability of Agrobacterium tumefaciens

“…Under normal conditions, nitrate is not a preferred nitrogen source for A. tumefaciens, but it is a major nitrogen source for plant growth and functions as a critical signal molecule regulating the whole plant development process (52)(53)(54). Nitrate is mainly taken up from the soil by plant roots, stored in vacuoles, and accumulated at the wound sites for healing (55). It has been reported that nitrate is capable of increasing the number of tumors on inoculated plant hosts by 200% (56).…”

Effects of NaCl stress on accumulation of K+, Na+, Cl-, NO3 -,sugar and proline contents in the seedlings of Triticale-I

“…Salinity stress caused an imbalance of nutrients in plants (Song et al 2006) due to the competition of Na + and Cl -with nutrients such as K + and NO 3 -(Jouyban 2012). Salt stress undesirably affects plant growth and productivity during all developmental stages (Abari et al 2011).…”