Distribution of VA mycorrhiza on halophytes on inland salt playas

The value of mycorrhizal association for higher plants has been well established. However, the impact of high salinity on the mycorrhizal relationship has not been investigated to any great extent. Inland salt playas represent an opportunity to test the impact of salinity because it is possible to obtain a gradient by following a transect from the centre of the salt playa to the higher outer zones. In a salt playa near Goshen, Utah, the sodium concentration ranged from 27,150 ppm in the centre to 25 ppm in the outer zone. In the playas with sodium concentrations of 20,000 ppm, no mycorrhiza were detected on the halophytes and no spores of mycorrhizal fungi were found in the soil. One percent of the roots of salt grass in soils containing 8,450 ppm of sodium were mycorrhizal. In soils containing 622 ppm of 45 percent of the roots of a salt-tolerant grass (hybrid ofAgropyron repens × Agropyron spicatum) were mycorrhizal. Halophytes such asSalicornia pacifica var.utahensis which are among the most salt tolerant halophytes of the inland salt playas rarely had mycorrhizal roots. The mycorrhizal associations appear to be very limited in inland salt playas with sodium content.