Enhanced Growth and Drought Resistance in Seedlings of Acacia tortilis due to Inoculation of Arbuscular Mycorrhiza Fungi and Bacillus subtilis

Abstract

A shade house experiment was conducted in Saudi Arabia to evaluate the impact of a mixture of three arbuscular mycorrhiza fungi (AMF) namely Funneliformis mosseae, Rhizophagus intraradices and Claroideoglomus etunicatum, a bacterium Bacillus subtilis, and their combinations on the growth and drought resistance potential of Acacia torilis seedlings under moderate and water deficit-stress. Thus, inoculants treatments (AMF, Bacillus subtilis, AMF+Bacillus, and control) and several watering intervals (1, 2, 3 and 4 weeks) were applied. Inoculation of AMF and Bacillus to A. tortilis seedlings found effective in terms of improved seedling growth. AMF and combined inoculation resulted in a larger shoot (shoot fresh and dry weights, seedling height, leaf number, leaf area) and root development (root fresh and dry weights, root length, root surface area, and root volume) as compared to the non-inoculated seedlings. Single inoculants of B. subtilis, showed better improvement in 1- and 2-week watering intervals compared to the control. Inoculated seedlings showed lower proline accumulation than non-inoculated seedlings, and thus improved seedling resistance to water deficit-stress. Mycorrhizal and mixed inoculation enhanced the amount of chlorophyll in the seedling’s leaves. Furthermore, seedlings with AMF and co-inoculants showed better drought tolerance even at 3- and 4-week watering intervals. © 2021 Friends Science Publishers