Response to water deficit of Nothofagus dombeyi plants inoculated with a specific (Descolea antarctica Sing) and non-specific (Pisolithus tinctorious (Pers.) Coker & Couch) ectomycorrhizal fungi

The influence of the specific Descolea antarctica (Da) and the non-specific Pisolithus tinctorious (Pt) ectomycorrhizal fungi on some physiological leaf parameters of the Chilean evergreen Nothofagus dombeyi subjected to a low soil water potential (-1.6 to -1.9 MPa in a growth chamber for 35 days) and a high water potential (-0.07 to -0.09 MPa, control) was studied. Drought decreased the water status and increased carbohydrates in mycorrhizal and non-mycorrhizal plants, appearing Da-mycorrhizal and non mycorrhizal plants better osmotically adjusted (OA= 0.60 MPa and 0.52 MPa, respectively) than Pt-mycorrhizal (0.39 MPa). Proline is not involved in the OA of mycorrhizal plants. The inoculation of N. dombeyi with both ectomycorrhizal fungi favored a better maintenance of the functionality of the photosynthetic apparatus under drought as indicated by the effective quantum yield (ΦPSII). It is concluded that both ectomycorrhizal and non-mycorrhizal N. dombeyi plants responded to water deficit with OA adjustment, having Da-mycorrhizal plants a greater OA than Pt-mycorrhizal plants.