Growth, mineral acquisition, and water use by mycorrhizal wheat grown under water stress

Abstract

Plants colonized with arbuscular mycorrhizal (AM) fungi generally have greater growth and acquisition of mineral nutrients, and often have greater ability to withstand drought compared to nonmycorrhizal (nonAM) plants. This study determined effects of water stress (WS) versus no WS (nonWS) and the AM fungus Glomus monosporum (AM vs nonAM) on growth, acquisition of phosphorus (P), zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe), and water use in two durum wheat (Triticum durum Desf.) cultivars exhibiting differences in resistance to WS. Plants were grown on soil [low P silty clay (Typic Xerochrept, pH=8.1)] and sand mixtures in a greenhouse. Shoot and root dry matter (DM), total root length (RL), and root colonization with AM for plants grown under non WS were higher than for plants grown under WS. Much of the reduction in DM was overcome by AM plants grown under WS. The ‘drought‐resistant’ wheat cultivar CR057 had higher AM root colonization than the ‘drought‐sensitive’ cultivar CR006 when grown with and without WS. Concentrations of P were lower and Zn, Cu, Mn, and Fe were higher in shoots of plants grown under WS compared to non WS. Nutrient contents were greater in AM than in nonAM plants, and these differences were greater under WS than under nonWS conditions. The AM plants had higher water use efficiency (WUE, g DM kg^‐1 water evapotranspired) values than nonAM plants when grown under WS. The cultivar CR057 generally had higher WUE values than CR006. The results of this study indicated that AM plants had greater tolerance to drought stress than nonAM plants.