Arbuscular mycorrhizal associations in the southern Simpson Desert

The plants of the Simpson Desert are adapted to one of the driest regions on the Australian continent and grow in generally nutrient-poor soils. Surveys were conducted at three sites in the southern Simpson Desert to determine the arbuscular mycorrhizal (AM) status of 52 species from 28 families of annual and perennial plants. Roots from all plants were examined for the presence of internal and external hyphae, vesicles, arbuscules and coils to determine presence and extent of mycorrhizal colonisation. Of the plant species surveyed, 38 (73%) had formed mycorrhizal associations. The AM status of 47 species is reported for the first time, including of members of the Frankeniaceae and Myoporaceae families. No correlations were found between site (dune or interdune) or life form and the number of species forming AM associations. Two species in the normally non-mycorrhizal Chenopodiaceae, Salsola kali L. and Sclerolaena diacantha (Nees.) Benth. had mycorrhiza. Arbuscules and/or vesicles were observed in the roots of all mycorrhizal plants except three species, Solanum ellipticum R.Br., Gnephosis eriocarpa (F. Muell.) Benth. and Eremophila longifolia (R.Br.) F. Muell., in which only coils of hyphae were observed.