ROLE OF PHOSPHORUS AND ARBUSCULAR MYCORRHIZAL FUNGI IN THE GROWTH PERFORMANCES AND TOLERANCE OF BARLEY TO WATER STRESS

Drought is one of the environmental constraints affecting crop productivity and food security in the world, especially in arid and semi-arid areas. Arbuscular mycorrhizal fungi (AMF) living in symbiosis with plant roots are registered candidates in the regulation of phosphorus (P) uptake by plants and promote their growth under severe drought conditions. This study was conducted to examine the effect of phosphorus (P, 50 mg kg-1) supplementation and the inoculation of arbuscular mycorrhizal fungi (Glomus mosseae, G. monosporus, G. versiforme) on growth and tolerance of barley (Hordeum vulgare L.) under water-limited conditions. The obtained results revealed that drought negatively affects mycorrhization parameters. AMF inoculation and P supplementation significantly improved growth parameters under well-watered conditions (75% of field capacity: FC) and under severe water stress (30% FC). In addition, mineral nutrients such as P, potassium (K), sodium (Na), magnesium (Mg) and calcium (Ca) were improved under both water regimes imposed on the soil in plants treated with P or AMF species. Phosphorus feeding and AMF inoculation also mitigated the drought-induced decline by improving leaf water potential and relative water content. G. mosseae differs from other fungal species in its ability to help the barley plants counteract the negative effects of drought. Indeed, barley plants not inoculated (Controls), not inoculated but fertilized with P and inoculated with G. versiforme have high amounts of proline. In this respect, we can conclude that optimization P fertilization and inoculation by AMF could be a biological strategy to satisfy and ensure water and mineral element requirements, as well as to protect barley plants against drought.