Interactive effects of salinity and potassium availability on growth, water status, and ionic composition of Hordeum maritimum

Abstract

The interactive effects of salinity and potassium (K+) availability on biomass production, water status, and ionic composition were investigated in Hordeum maritimum, an annual grass growing natively on saline soils. Plants were grown for 7 weeks on Hewitt nutrient solution supplied with NaCl (0, 100, 150, 200, and 300 mM) combined with low (0.232 mM) or high (5.8 mM) K+ levels. Independent of potassium availability, dry matter of both roots and shoots decreased consistently with increasing NaCl levels in the culture medium, in association with a significant reduction of the shoot water content. This salt‐induced growth reduction did not result from a restriction of K+ nutrition, since H. maritimum expressed similar growth under both low and high K+ supply. NaCl decreased shoot K+ concentrations. This effect was more pronounced in plants grown at high K+ supply than in plants grown at low K+ supply. This result suggests that the absorption systems were strongly selective for K+, and that this selectivity was enhanced by salt.

Alleviation of phosphorus deficiency stress by moderate salinity in the halophyte Hordeum maritimum L.

“…S plants is very efficient. These findings are consistent with those of Hafsi et al (2007) who showed that the osmotic effect was limited in H. maritimum and found that tissue water content remained relatively high in shoots (80% of fresh weight) even at 300 mM NaCl. It is remarkable that despite this enhancement of stomatal closure, instantaneous CO 2 assimilation rate quantified in the presence of salt and low P (A) was surprisingly increased by NaCl in young leaves of P-deficient plants.…”

“…Na ? ) of the ion concentrations (mM) in the nutrient medium of H. maritimum shoots (Hafsi et al 2007). …”

“…In Tunisia, this plant is often observed at the close vicinity of strict halophytes in saline depressions, where it significantly contributes to the annual biomass production (Abdelly et al 1995). Hafsi et al (2007) showed that this plant appears to be a promising species for fodder production in saline soils, because it is able to cope with both salt stress and potassium deficiency notably due to a strong K ? uptake selectivity in spite of Na ?…”

Antioxidative response of Hordeum maritimum L. to potassium deficiency

“…For instance, in saline soils, plants may suffer from a dual injury: sodium toxicity and potassium deficiency (Rubio et al 1995;Schachtman 2000) owing to competition between potassium and sodium ions to enter plant cells because they are similar in ionic radius and ion hydration energies (Schachtman and Liu 1999). The annual facultative halophyte Hordeum maritimum, potentially useful for forage production in saline zones, can survive up to 300 mM NaCl under potassium-deficient conditions (Hafsi et al 2007). As this species is tolerant to K ?…”

Impact of a natural soil salinity gradient on fungal endophytes in wild barley (Hordeum maritimum With.)

“…; Family Poaceae). This is a Mediterranean wild grass typical of saline coastal or inland meadows (Lombardi and Lupi 2006), making it potentially useful for fodder production in saline zones (Hafsi et al 2007).…”