Delayed modifications in plant-water relations in the coastal marsh halophyte Spartina patens following sudden increases in soil salinity

Abstract

Little is known about how upper marsh plants (growing in freshwater) will respond physiologically to sudden increases in salinity. In this study, we used experimental microcosms to evaluate changes in plant-water relations in the halophyte Spartina patens following increases in soil salinity (salinity levels: 15, 30, and 45). There was a delay (by 3–5 weeks) in the lowering of leaf water potential (ψleaf), stomatal conductance (g), and tissue water content (θ) in plants subjected to salinities of 30–45. These physiological delays in plant-water adjustments following sudden increases in salinity may be an adaptation of S. patens that allows it to effectively exploit higher habitat elevations that receive intermittent seawater inundations without promoting costly physiological modifications.

Salt tolerance of Beta macrocarpa is associated with efficient osmotic adjustment and increased apoplastic water content

“…At both salinity concentrations, this change in leaf Ψs 100 (DΨs 100net ) was about 0.6 MPa (Table 1), indicating that the maximum reduction was achieved at 100 mM NaCl, and that this plant cannot reduce its osmotic potential beyond this external salt concentration. The present results are in line with those of Saltpeter et al (2012), who showed that low water availability together with the presence of salt in the environment causes active osmotic adjustment. Thus, osmotic adjustment is, perhaps, the main adaptive mechanism used by plants to limit the osmotic effects of salt stress (Saltpeter et al 2012;Flowers et al 2015).…”

“…The present results are in line with those of Saltpeter et al . (), who showed that low water availability together with the presence of salt in the environment causes active osmotic adjustment. Thus, osmotic adjustment is, perhaps, the main adaptive mechanism used by plants to limit the osmotic effects of salt stress (Saltpeter et al .…”

“…Thus, osmotic adjustment is, perhaps, the main adaptive mechanism used by plants to limit the osmotic effects of salt stress (Saltpeter et al . ; Flowers et al . ).…”

“…However, the effect was higher at 200 mM than at 100 mM NaCl. This change can contribute to passive concentration of solutes and thus to turgor maintenance in stressed plants (Touchette et al 2009;Saltpeter et al 2012).…”

Bulk elastic moduli and solute potentials in leaves of freshwater, coastal and marine hydrophytes. Are marine plants more rigid?

“…As mentioned, several studies have shown strong associations between elevated environmental salinities and increased tissue rigidities ( Bolaños and Longstreth 1984 ; Salpeter et al 2012 ). These findings, in general, suggest that marine halophytes should have higher ɛ values compared with freshwater or terrestrial plant species.…”