VESICULO ARBUSCULAR MYCORRHIZAE ASSOCIATED WITH SALTBUSHES ATRIPLEX SPP. (CHENOPODIACEAE) IN THE CHILEAN ARID ZONE

The family Chenopodiaceae is represented in arid plant communities wor ldwide. Chenopodiaceae have been usually defined as non-mycorrhizal; h owever, recently some species of the genus Atriplex in North America h ave been shown to be mycorrhizal. We determined the vesiculo arbuscula r mycorrhizal (VAM) status of nine species of Atriplex spp., including nine populations of A. repanda, three of A. atacamensis, two of A. mu dariagae and A. mucronata, and one of A. podocarpa, A. coquimbensis, A . deserticola and A. microphylla, and two plantations of the exotic sp ecies A. nummularia in the Chilean Pacific coastal desert. Localities and species showed large differences in number of VAM spores and perce ntage of VAM infection. Number of VAM spores and percentage of VAM inf ection were positively correlated with available nitrogen in the soil. Percentage of VAM infection was also negatively correlated with soil salinity. Considering all populations, we found in the field on the av erage 32% infection and 45 VAM spores/100 g soil. Although the infecti on percentage was low, this may allow land managers to select VAM stra ins to inoculate Atriplex plants used to reclaim disturbed Chilean ari dlands.