Varied rates of mycorrhizal inoculum on growth and nutrient acquisition bybarley grown with drought stress

Effectiveness of arbuscular mycorrhizal fungi (AMF) is crucial for maximum plant growth and acquisition of mineral nutrients under drought. The object ive of this research was to determine effects of varied rates of AMF inocul um on plant growth and acquisition of phosphorus (P), zinc (Zn), copper (Cu ), and manganese (Mn) by barley (Hordeum vulgare L. cv. SLB-6) grown with a nd without drought stress (WS and nonWS). Plants inoculated with four inocu lum rates [control(M-0), 120 (M-1), 240 (M-2) and 360 (M-3) spores per 100 g dry soil] of Glomus mosseae were grown in a low P silty clay (Typic Xeroc hrept) soil (pH=8.0) mix in a greenhouse for 45 days. Root AMF colonization increased as inoculum rate increased in plants grown with WS and nonWS. Le af area and shoot and root dry matter (DM) increased as inoculum rate incre ased up to M-2 regardless of soil moisture. Shoot concentrations of P, Cu, and Mn were generally higher for mycorrhizal (AMF) than for nonmycorrhizal (nonAMF) plants grown with bath WS and nonWS. Shoot contents of P, Zn, Cu, and Mn were higher for AMF than for nonAMF plants grown with nonWS, and sho ot contents of P were higher for AMF than for nonAMF plants with WS. For Pl ants grown with WS and nonWS, contents of P, Zn, Cu, and Mn were generally higher for plants inoculated with M-2 compared to other rates of inoculum. The results of this study indicated that plant responses to root colonizati on with AMF were dependent on AMF rate and soil moisture. Eased on enhancem ents in plant DM and mineral acquisition traits, M-2 inoculum was the most effective rate of inoculation for this AMF isolate.