Arbuscular mycorrhizal fungi improve the growth of olive trees and their resistance to transplantation stress

Two native Algerian mycorrhizal fungi (Glomus mosseae and Glomus intraradices) were tested for their effect on the growth of micropropagated olive tree (Olea europaea L.). The effect of inoculation of plantlets with G. mosseae was also compared with chemical fertilization using osmocote. Specific molecular techniques were then used to detect the presence of the two fungi. Highly significant increases in growth were evident for inoculated plants compared with uninoculated ones. For a slightly lower shoot growth, G. mosseae doubled the root growth of the inoculated plantlets, compared to that of the fertilized plants. This change in the root: shoot ratio permitted greater utilization of soil resources and strengthened the plant's capacity to resist transplantation shock and water stress. The abundance of the two fungi in the roots of wild olives just as in the inoculated olives is indicative of the predominance of G. intraradices when the natural microflora is present.