Provenance causes variation on early growth and survival and sun protection on physiological responses of the vulnerable Nothofagus glauca (Phil.) Krasser in a common garden in Central Chile

Abstract

We assessed outplanting performance of N. glauca in two trials. In Trial 1, provenances from Pre- Andean (Linares, Longaví) and Coastal (Curanipe, Empedrado) origins were planted in a common garden under two sun protection treatments (i.e., black mesh shelter, and kaolin at 6% concentration), and a control treatment at full sun. In Trial 2, a local provenance was established under two site preparation treatments (i.e., old subsoiling from 4 years ago versus no-subsoiling). Growth, survival, gas exchange, and Chlorophyll fluorescence parameters were measured one year after outplanting. In Trial 1 survival was similar among treatments but larger seedlings were found under kaolin and in the local provenance Empedrado. The provenances varied by sun protection treatment in survival, and the Pre Andean provenance Linares tended to show the lowest survival at full sun. At the leaf-level physiology, provenances responded similarly in gas exchange and fluorescence parameters. In the sun protection treatments seedlings under kaolin increased stomatal conductance and electron transport, but decreased photosynthesis, water use efficiency, and efficiency of PSII. Provenances also varied by treatment in physiology. The Empedrado provenance exhibited the highest transpiration and stomatal conductance under kaolin whereas the Pre Andean provenance of Longaví showed the lowest photosynthesis and efficiency of PSII in the kaolin treatment. In Trial 2, root collar diameter, intercellular CO2 and water use efficiency were higher in the old-subsoiling treatment. As a potential adaptation tool, seed sources from Pre Andean origins can be established in Coastal origins with no detriments on seedling survival.