Accumulation of NaCl in Lampranthus spectabilis under high salt soil conditions

Abstract

Lampranthus spectabilis (Aizoaceae) is a perennial plant that is common in Japanese urban settings, such as roadsides and parks. To investigate its ability to accumulate NaCl in saline soil, we grew plants in 0-, 100-, 200-, 400-, or 600-mM NaCl solutions and collected samples at 1, 2, 3, and 6 weeks. Plants grew in NaCl concentrations that were above the target electrical conductivity value for leaching in Japan. With increasing NaCl concentrations, Na⁺ contents in leaves and stems increased remarkably, and were accumulated to more than 2 fold that in roots. Under the same conditions, Cl⁻ accumulated in leaves and stems to 10 times that in roots. Furthermore, at 100- to 400-mM NaCl, plant water contents were equivalent to those in control plants. These data suggest that leaves and stems avoid the adverse effects of salt by maintaining high water contents. At 6 weeks, ion contents in leaves and stems reached 45 mg of Na⁺ g⁻¹DW and 163 mg of Cl⁻ g⁻¹DW at 400-mM NaCl, and reached 102 mg of Na⁺ g⁻¹DW and 135 mg of Cl⁻ g⁻¹DW at 600-mM NaCl. The ability of L. spectabilis to accumulate high levels of NaCl may make it suitable for phytoremediation of salinized soils.