CONICET | Buscador de Institutos y Recursos Humanos

High quality seedlings are needed to increase the success of restoration projects in drylands. Nursery techniques can help reducing seedling vulnerability to drought and improving field performance. Drought preconditioning has been used in drylands worldwide to improve seedling establishment in drought-prone areas. In this study, we assessed the effect of drought preconditioning on the morphology, biomass partitioning and non-structural carbohydrates concentration of seedlings of Senecio subulatus, a keystone ruderal species in Monte Desert, Argentina. We then related morpho-functional traits with field survival and growth after transplanting to a degraded area. We applied two drought preconditioning treatments (watered when soil water content decreased by 50% and 80% from field capacity -mild and severe preconditioning respectively-) in the nursery and measured seedling morphology and non-structural carbohydrates at the end of this period. Then, we planted seedlings in a degraded area and monitored survival and growth for one year. Severe preconditioning reduced stem diameter, biomass accumulation and leaf weight ratio, and had no effect on the shoot-to-root ratio, as compared to milder preconditioning. Furthermore, severe preconditioning increased non-structural carbohydrate concentration in roots and decreased their concentration in shoots. One year after planting, seedling survival was high under both treatments (100%). Stem diameter growth was higher in seedlings under severe drought, and thus, stem growth did not correlate with initial seedling diameter. Drought preconditioning seems to be a suitable technique to improve field performance in S. subulatus in the short term. Further monitoring will confirm if the short-term trends are maintained.