Effects of Mycorrhizae on Sorghum Growth, Photosynthesis, and Stomatal Conductance under Drought Conditions

In this study, we determined whether inoculating sorghum ( Sorghum bicolor ( L.) Moench cv NK-367) seedlings with a vesicular arbuscular mycorrhizal (VAM) fungus (Glomus intraradices Schenck and Smith) would enhance plant yield under drought conditions. Seven-day-old seedlings were inoculated with the fungus and irrigated to field capacity for an additional 7 days. Daily irrigation treatments of I-1 (dry, -0.56 to -1.4 MPa), I-2 (moderately dry, -0.15 to -0.48 MPa), and I-3 (wet, -0.03 to -0.06 MPa) were then imposed with a line-source sprinkler. Under moderately dry soil conditions, growth, photosynthetic rate, and stomatal conductance of G. intraradices-colonized sorghum plants were significantly greater than in uncolonized plants. Results indicate that the VAM fungus enhanced yield of sorghum plants under drought conditions.