Mycorrhizal inoculation and nitrogen fertilization affect the physiology and growth of spring wheat under two contrasting water regimes

Abstract

Most plants benefit from mycorrhizal symbiosis through their improved abilities to take up nutrients and water. Information on the interactive effects of fungal inoculation, nitrogen (N) fertilization and drought on water use efficiency (WUE) and productivity of Canadian wheat varieties is scanty. In this study, we investigated the effects of arbuscular mycorrhizal fungi (AMF) inoculation, N fertilization and water regime (well-watered (WW) vs water-deficit (WD)) on WUE, phosphorus (P) and N uptake and growth of spring wheat (Triticum aestivum var. Superb) in a greenhouse experiment. The specific leaf area (SLA) of flag leaves was significantly increased by AMF inoculation under the two water regimes but was lowered under N fertilization and drought conditions. The AMF inoculation significantly enhanced relative water content under WD. The WUE and instantaneous WUE (WUEi) were enhanced by N fertilization and AMF inoculation under both water regimes. Combined N fertilization and AMF inoculation significantly increased N concentrations in stem and grain, plant height, biomass and grain yield under WD. The P concentrations in stem and grain were increased under WD, irrespective of other treatments applied. The WUE and grain N, stem N, and P concentrations were positively correlated. Plant physiological characteristics were negatively affected by WD, while N fertilization and AMF inoculation enhanced plant performance under WD, including the increase of N and P concentrations in different componments of spring wheat.