Ion homeostasis in differently adapted populations of Suaeda vera Forssk. ex J.F. Gmel. for phytoremediation of hypersaline soils

Abstract

Salt-accumulator species are of great interest for the phytoremediation of salt-affected soils to reclaim soil salinization, a major constraints causing germination retardation and growth restriction of plants as well as habitat degradation. Higher biomass production at ECe 23–36 dS m⁻¹ indicated that this species grows better in high to moderate salinity that was linked to osmotic adjustment through higher ion accumulation (Na⁺, Cl^‒, and Ca²⁺) and organic osmolytes (free amino acids and proline). Plants from highly and moderately saline habitats exhibited broader metaxylem vessels, which was associated with eased conduction of solutes leading to better growth. Leaf anatomical characteristics generally increased with increasing salinity except at the highest ECe 55 dS m⁻¹. The increased leaf lamina thickness contributed to succulence because of increased storage parenchymatous spongy tissues (that can store high amounts of water), water contents and it is a reflection of maintaining ion homeostasis and colonizing hyper-saline soil. Reduced stomatal density and area under high salinity are critical to cope with environmental hazards. Under high salinity, compartmentalization of excessive Na⁺ and Cl⁻ ions and accumulation of compatible osmolytes are directly related to high degree of salinity tolerance, and hence are useful for phyto-amelioration of salinity-impacted lands.

NOVELTY STATEMENT

Salinity tolerance mechanism in Suaeda vera have been explored extensively, but these mechanisms have not been addressed in the context of soil-plant interaction and functioning connection between structural and functional features with respect to phytoremediation. This work aims to provide mechanistic insight into how different morphological and physio-anatomical mechanisms in differently adapted population of Suaeda vera operate in coordinated manner to maintain ionic homeostasis under high salinity that are useful for phytoremediation.

Keywords:

• Succulence
• organic osmolytes
• sclerenchyma
• ion accumulation
• storage parenchyma