Leaf–water relations and ion concentrations of the halophyte Atriplex hortensis in response to salinity and water stress

Abstract

The impact of salinity and water stress was analyzed in the xero-halophyte Atriplex hortensis using two varieties: green orach (A. hortensis var. purpurea) and red orach (A. hortensis var. rubra). A. hortensis L. is a C 3 species well adapted to salt and drought conditions. To collect information on the physiological impact of different salt and water deficit levels on their water stress resistance, plants were exposed for 3 months to solution containing four levels of NaCl or to water stress regimes including four levels of field capacity. Osmotic potential at zero turgor W s 0 , osmotic potential at full turgor (W s 100 ), relative water content (RWC), ion concentration (Na ? , K ? , Ca 2? , Mg 2? , and Cl -), and malondialdehyde (MDA) were determined at the end of the treatment. The salinity and water stress induced a decrease in W s 100 , W s 0 , and RWC in both varieties, recorded changes being higher in plants of red variety than those of green variety. Both varieties specifically accumulated Na ? in response to drought and salt stress, suggesting that this element could play a physiological role in the stress response of this xero-halophyte species. In contrast, the presence of NaCl and water stress induced a decrease in K ? , Ca 2? , and Mg 2? concentration in both varieties. Salinity clearly induced an increase in Cl -concentration in all tissues, but water stress had no impact on this parameter. MDA concentration increased in response to water stress and exogenous NaCl. Based on these findings the more drought-tolerant red orach may be grown in water-limiting soils.

The elemental composition of halophytes correlates with key morphological adaptations and taxonomic groups

“…These trends were not so clearly seen in perennial species, where several succulent and semi-succulent plants showed high Ca concentrations (potentially the same species that showed a tendency to accumulate S and could be growing on gypsum-rich soils). Our findings for annual plants are in agreement with several previous reports on the incompatibility of Ca and Na in plant cells under salt stress (Grattan and Grieve, 1992;Kachout et al, 2011;Krüger and Peinemann, 1996;Naidoo, 1994;Tipirdamaz et al, 2006). Furthermore it may be explained by the lower selectivity of Ca under high Na by transport systems and the ability of pseudo-halophytes and facultative-halophytes to favor Ca and avoid Na uptake when growing in saline environments (Albert and Popp, 1977;Grattan and Grieve, 1992;Kudo et al, 2010).…”

“…2, Table 4). Previous studies have shown similarly high Na and reduced K concentrations in halophytes (Grattan and Grieve, 1992;Gulzar et al, 2003;Kachout et al, 2011;Noaman, 2004;Parida and Das, 2005;Taleahmad et al, 2013). Potassium is an essential macronutrient in plant cells, with a key role in many important physiological processes, such as the regulation of stomatal functions, or the adjustment of cell water potential (Noaman, 2004;White and Karley, 2010).…”

“…The relationship between the chemical composition of plants and saline condition is of great importance to understand plant adaptation under high salinity. Low leaf K, Ca, and Mg concentrations along with the accumulation of Na were documented in plants growing in high salinity, and have been recorded for some eu-halophytes including many Chenopodiaceae (Albert and Kinzel, 1973;Albert and Popp, 1977;Gulzar et al, 2003;Kachout et al, 2011;Khan et al, 2000a, b;Kudo et al, 2010;Milić et al, 2013;Wiebe and Walter, 1972;Zoerb et al, 2013). Several studies have shown that the accumulation of certain elements in the leaves of some species of eu-halophytes is genetically controlled with poor dependency on the condition of their rhizospheres (Albert, 1982;Breckle, 1986;Krüger and Peinemann, 1996;Matinzadeh et al, 2013).…”

Physiological and Biochemical Responses of Semiarid Plants Subjected to Water Stress

“…However, K + , Ca 2+ and Mg 2+ decreased in response to water and salt stress. Cl -concentration increased in response to salt stress in all tissues, but water stress had no impact on this parameter (Kachout et al, 2011). Regarding osmoregulation in the coconut palm, proline's contribution to the overall osmotic adjustment in ecotypes of BGD was recently shown to be low (Gomes et al, 2006;Gomes & Prado, 2007) because: (1) proline concentration was reduced to control levels upon rewatering, whereas osmotic potential did not increase and even decreased in re-watered plants; and (2) the patterns of the two coconut ecotypes evaluated for proline accumulation did not reflect their relative behaviors in terms of osmotic adjustment.…”

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

“…Data include species, taxonomic family, habitat (freshwater, coastal or marine), growth form (forb-herb, graminoid or shrub), environmental conditions at the time of collection (including salinity for marine plants; in practical salinity units [psu]) and the reference or source of the data.SpeciesFamilyHabitatGrowth/habitEnviron. conditions/salinitySource Acorus americanus AcoraceaeFreshwaterForb-herbBioretention basin (flooded)This study Acorus americanus AcoraceaeFreshwaterForb-herbGreenhouse (flooded)Romanello et al (2008) Arundinaria gigantean PoaceaeCoastalGraminoidDamp soils 100 m from seawaterThis study Atriplex hortensis ChenopodiaceaeFreshwaterForb-herbGreenhouseKachout et al (2011) Bidens sp.AsteraceaeFreshwaterForb-herbGreenhouse (saturated soils)This study Borrichia frutescens AsteraceaeMarineShrubUpper salt marsh/32 psuThis study Carex alata CyperaceaeFreshwaterGraminoidGreenhouse (flooded)Touchette et al (2007) Carex alata CyperaceaeFreshwaterGraminoidGreenhouse (saturated soils)This study Cephalanthus occidentalis RubiaceaeFreshwaterShrubLacustrine wet shorelineThis study Eleocharis sp.CyperaceaeFreshwater…”