EFFECT OF SAPROTROPHIC FUNGI ON ARBUSCULAR MYCORRHIZAL ROOT COLONIZATION AND SEEDLINGS GROWTH IN DATE PALM UNDER GREENHOUSE CONDITIONS

The interactions between the arbuscular mycorrhizal fungi (AMF) Glomus mosseae (Gm) and Glomus intraradices (Gi) and the saprophytic fungi Trametes versicolor (Tv) and Fusarium lateritium (Fl) on arbuscular mycorrhizal root colonization and date palm growth were studied in greenhouse experiments. Overall, the results indicated that mycorrhizal inoculation improved date palm growth since biomass production was higher in mycorrhizal than in non-mycorrhizal seedlings. Nitrate reductase (NR) and glutamine synthetase (GS) activities were significantly higher in AMF plants compared to non-AMF plants. Date palm root colonization with Gm was significantly enhanced in the presence of the saprophytic fungus Trametes versicolor. The double inoculation with Glomus mosseae and Trametes versicolor showed higher biomass production and higher NR and GS activities. However, low NR and GS activities and biomass was produced by mycorrhizal plants when Fusarium lateritium was present. Thus, the effectiveness of the double inoculation in improving the growth of date palm varied among mycorrhizal and saprophytic fungi species, the interaction Gm/Tv being the most effective association to enhance date palm development.