Effect of glyphosate on germination and seedling development of four native plants of dunes in Spain

Using glyphosate is easier than manually controlling the invasive plant Carpobrotus in dune ecosystems. However, before it is used its effect on native species in this ecosystem needs to be determined. This study reports the effects in the laboratory of different concentrations of glyphosate (1.0, 0.5, 0.3, 0.1, 0.05, 0.01, and 0.005 g/m2 ) on germination and seedling emergence of four species of Mediterranean dune plants, Lotus creticus, Medicago marina, Ononis ramosissima and Ammophila arenaria, used in the restoration of this natural ecosystem. Germination was completely inhibited when glyphosate was applied at 0.5, and 1.0 g/m2. The recommended dose (0.3 g/m2 ) also inhibited the germination of L. creticus and M. marina. The percentage germination of O. ramosissima and A. arenaria was around 40% and 30% respectively when a dose of glyphosate of 0.1 g/m2 was used, whereas for seeds of L. creticus and M. marina it was lower than 5%. The T50 at germination of seed incubated with glyphosate increased in all species independently of the dose of glyphosate. Seedling emergence from seeds previously germinated in the presence of glyphosate was only recorded for O. ramosissima and A. arenaria. The results indicate that seeds of O. ramosissima are more tolerant of glyphosate, followed by those of A. arenaria and those of L. creticus and M. marina are the most sensitive.