Germination and seedling growth of Hydrocotyle bonariensis Lam. (Apiaceae) in different concentrations of NaCl

Abstract

Hydrocotyle bonariensis seeds were germinated at five constant concentrations of NaCl (zero, 15, 30, 60 and 120 mM NaCl) and three recovery conditions from salt exposure (seed were soaked in 600 mM NaCl seawater) for 15, 30 and 45 days and afterwards transferred to distilled water. Additionally, survival and growth of seedlings were tested in six constant salinity regimes (zero, 5, 10, 20, 40 and 80 mM NaCl). Germination tests indicate that H. bonariensis seeds germinate better in freshwater, decreased gradually with the increase in NaCl concentration. Germination was completely inhibited at 120 mM NaCl. Seedling biomass, number of leaves and leaf size were progressively reduced with increase in NaCl concentration. The decrease of viability after high salt exposure, low germination and growth at high NaCl concentration are probably the determinant causes of the restrict distribution of Hydrocotyle bonariensis to stable and no-salt areas of coastal dunes.