Abstract
The present research was undertaken to explor the possibility of arbuscular mycorrhizal (AM) association with Asteraceae plants in the arid lands of Saudi Arabia (Al-Ghat, Buraydah, Thumamah and Huraymila). AM fungal colonization in the roots, spore numbers in the rhizosphere soil, fungal species diversity and correlation between AM properties and soil properties were determined. The highest colonization was in Conyza bonariensis (65%) from Al-Ghat, Anthemis cotula (52%) from Buraydah and C. bonariensis (53%) from Thumamah. The lowest was in Vernonia schimperi (41%) from Al-Ghat, Pulicaria undulata (25%) from Buraydah, Acanthospermum hispidum (34%) from Thumamah, Asteriscus graveolens (22%) and V. schimperi (22%) from Huraymila. Vesicular and arbuscular colonization were also presented in all plant species examined. The number of spores were 112-207 in Al-Ghat, 113-133 in Buraydah, 87-148 in Thumamah and 107-158 in Huraymila. Funneliformis mosseae, Glomus etunicatum, G. fasciculatum and G. aggregatum were identified. Relative frequency of AM fungal species varied widely and was irrespective of location and plant species. Diversity index varied with the rhizosphere soils of different plant species at various locations. Soil properties varied with locations and no distinct correlations were observed among the soil properties, root colonization and the number of spores. The results of the present study specified the association of AM fungi in different plants of Asteraceae and its significance in the ecological functioning of annual plants in the punitive environments of the rangelands in Saudi Arabia.