The potential of Alternanthera littoralis P. Beauv. for saline soil phytoremediation and use as animal feed

Abstract

Soil salinization is an increasing global concern, demanding sustainable strategies for agricultural recovery and food security. Halophytes such as Alternanthera littoralis P. Beauv. represent a promising alternative for phytoremediation and forage production in saline environments. This study evaluated gas exchange, effective quantum yield of PSII (ΦPSII), electron transport rate (ETR), antioxidative enzyme activity, and nutritional composition of A. littoralis under 0, 100, 200, and 300 mM NaCl. The species showed high salinity tolerance, with preferential Na⁺ accumulation in shoots (up to 84.51 g kg⁻¹ dry mass at 300 mM NaCl) and maximum accumulation in roots (21.94 g kg⁻¹ at 200 mM), highlighting its potential for Na⁺ phytoextraction. Despite increasing salinity, A. littoralis maintained stable ΦPSII and electron transport rate (ETR) values under saline conditions, indicating maintenance of photochemical activity. Leaf SOD activity increased under saline conditions, whereas MDA, H₂O₂, and electrolyte leakage did not differ among treatments, suggesting activation of antioxidative defense response without evidence of severe oxidative damage. Bromatological analyses revealed high protein content, reduced acid detergent fiber, and increased concentrations of essential minerals. These compositional changes were associated with higher in vitro dry matter digestibility under increasing NaCl concentrations, suggesting a potential forage application for the species under saline conditions. Collectively, these findings demonstrate the remarkable salinity tolerance of A. littoralis, highlighting its ability to maintain physiological functionality under saline conditions. In addition, the species shows potential as a multifunctional resource for the recovery of salt-affected soils and as a nutritious forage in saline environments.