Ranking of 11 coastal halophytes from salt marshes in northwest Turkey according their salt tolerance

Abstract

Salt-affected soils with high electrolyte contents limit the development of the majority of plants and serve as a habitat only for such species (halophytes) that can survive the conditions. To date, there is still much that is unknown about the physiological mechanisms, including ion relationships, that make plants salt-resistant. The primary aim of this study was to evaluate a method of ranking plants for their salt tolerance. A total of 11 coastal halophytes of the Kavak Delta were evaluated for their ability to cope with different soil salinities. For this, electrical conductivities of soils (of up to 135 dS m -1 ) were recorded and a total of 100 plant samples, including plant roots, were taken from a depth of 0-15 cm in the soil. The halophytes were ranked in the following order from highest to moderate salt tolerance: Halocnemum strobilaceum ≥ Salicornia fragilis ≥ Arthrocnemum fruticosum = Suaeda prostrata ≥ Salsola kali = Petrosimonia brachiata ≥ Juncus maritimus = Aeluropus littoralis ≥ Halimione portulacoides = Limonium graecum ≥ Artemisia santonicum. The Na + /K + ratios of leaves perfectly reflected the salinity tolerance ranking of all halophytic species examined. It proved possible to rank the salt tolerance of halophytes by assessment of the electrical conductivity of the soil in which they grew naturally; tolerance was well predicted by the Na + /K + ratio in the shoots.

Response to Hypersalinity of Four Halophytes Growing in Hydroponic Floating Systems: Prospects in the Phytomanagement of High Saline Wastewaters and Extreme Environments

“…Such a morphological trait enables the plant to better regulate the internal ion amounts, maintaining high and constant the translocation and accumulation of Na in the shoot, despite the high external concentrations of 30, 50, and 100 g L −1 NaCl tested. Few works reported the Na content of H. strobilaceum [38], while most studies correlate the spatial distribution of this species with soil or ecosystem salinity, e.g., [18,20,21,39,42], and, to our knowledge, none of these studies describes the cation and sodium contents in different organs as in this work. Both in S. fruticosa and H. strobilaceum, the Na concentrations of the stem and root progressively increase with increasing NaCl treatment, reflecting the Na uptake and translocation capacity of these organs.…”

“…Under the same conditions, the lower salinity levels of 75 mM (4.4 g L −1 ) NaCl stimulated the growth of J. maritimus, while it was inhibited at higher NaCl concentrations (150 and 300 mM NaCl) [46]. Juncus maritimus is able to grow in salt marshes and wetlands in the temperate regions of the world, including the Mediterranean Basin [31,42]. However, in both labscale and field work, J. maritimus grew under moderate or high salinity levels, never in hypersaline conditions (>30-35 g L −1 , i.e., 513-600 mM) comparable to those studied in our experiment.…”

“…Several studies [37][38][39][40] have been conducted on the germination of H. strobilaceum seeds under saline conditions, whereas few works focus on this species response at other phenological stages [38,41]. However, interesting works on relationships between the composition and distribution of vegetation and environmental salinity identify H. strobilaceum among the most tolerant species to soil salinity and establish its relevance as a useful indicator for monitoring activities [18,20,42]. Both S. fruticosa and H. strobilaceum are euhalophytes, that is, obligate halophytes, and the former is a succulent type while the latter is a xerophytic one with partially succulent shoots [41,43].…”

Morphological, physiological and biochemical aspects of salt tolerance of halophyte Petrosimonia triandra grown in natural habitat

“…Petrosimonia species, members of Chenopodiaceae family, are typical halophytes native to South East of Europe (Edmondson 1993;Grigore et al 2012;Todorova et al 2014) and regionally in Asia (Breckle et al 2011;Zörb et al 2013).…”

“…All Petrosimonia species identified are living in saline soils with 2 -28 dS m -1 EC (Grigore et al 2012;Zörb et al 2013;Todorova et al 2014), reaching up to 0.5 m height in arid areas. Although very little information is published about this species, it has been proposed as an antioxidant source for the expanding food crisis (Grigore and Oprica 2015).…”