Impact of mycorrhizae and irrigation in the survival of seedlings of Pinus radiata D. Don subject to drought Impacto de la inoculación con micorrizas y el riego en la sobrevivencia de plántulas de Pinus radiata D. Don sometidas a sequía

In drought condition, plants increase survival chance by adjusting their functional traits and by biological associations. Mycorrhizae association and artificial watering have been shown to increase plant survival under drought, especially at early developmental stages when plants are more susceptible. In Chile, Pinus radiata is the most important forest species. It is grown mainly in Central Chile, where precipitations are predicted to drop in 40% and change in frequency in the future due to climate change. Rhizopogon luteolus is an ectomycorrhizae usually associated with Pinus species and has been found to increase drought tolerance. We addressed the effect of R. luteolus inoculation on survival and functional traits of P. radiata seedlings exposed to two watering treatments. These treatments simulated control (50 ml) and 40% reduced precipitations (20 ml). We also evaluated the combined effect of watering quantity (20 and 50 ml) and frequency (every 5, 10 and 30 days) on the same variables. R. luteolus inoculation increased seedling survival, but reduced plant size. Watering quantity affected plant survival only at intermediate watering frequencies, but not at the high and low frequencies. The lowest frequency, normal for the summer of Central Chile, resulted in -80% seedling mortality. Most of the functional traits measured were not affected neither by watering frequency nor quantity, but they were affected by mycorrhization. Mycorrhizae inoculation, together with some sort of artificial watering could be a possible strategy to cope with prolonged drought events. En condiciones de sequía, las plantas aumentan la probabilidad de sobrevivir ajustando sus rasgos funcionales y por medio de asociaciones biológicas. Las asociaciones micorrícicas y el riego artificial aumentan la sobrevivencia en condiciones de sequía, especialmente en etapas tempranas del desarrollo, cuando las plantas son más sensibles. En Chile, Pinus radiata es la especie forestal más importante. Se planta principalmente en Chile central, donde se predice que las precipitaciones disminuirán en un 40% y cambiará su frecuencia en el futuro debido al cambio climático. Rhizopogon luteolus es una ectomicorriza usualmente asociada a especies de Pinus y se ha encontrado que aumenta la tolerancia a la sequía. Se analizó el efecto de la inoculación de R. luteolus en la sobrevivencia y rasgos funcionales de plántulas de P. radiata expuestas a dos tratamientos de riego. Estos tratamientos simulan precipitaciones control (50 ml) y reducidas a un 40% (20 ml). También se evaluó el efecto combinado d