Influence of plant growth-promoting rhizobacteria on corn growth under drought stress

Authors: LIN, YARU - Auburn University; Watts, Dexter; KLOEPPER, JOSEPH - Auburn University; FENG, YUCHENG - Auburn University; Torbert, Henry - Allen

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2019
Publication Date: 12/23/2019
Citation: Lin, Y., Watts, D.B., Kloepper, J.W., Feng, Y., Torbert III, H.A. 2019. Influence of plant growth-promoting rhizobacteria on corn growth under drought stress. Communications in Soil Science and Plant Analysis. 51(2):250-264. https://doi.org/10.1080/00103624.2019.1705329.
DOI: https://doi.org/10.1080/00103624.2019.1705329

Interpretive Summary: Plant water stress often affects the growth and yield of agricultural crops worldwide. It is believed that some bacterial strains found living in soil near plant roots can improve the tolerance of plants during water stress. This study evaluated the effects of two mixtures of soil bacteria known to promote plant root growth (plant growth-promoting rhizobacteria; PGPR) on the growth of corn under water stressed conditions. Urea and poultry litter were used as the fertility sources for this study. Plant growth was affected by how frequently the plants were watered. Plant receiving more water had greater plant biomass. Compared to poultry litter, urea application had more plant growth. Amending the soil with plant-growth promoting rhizobacteria improved plant growth and enhanced the root growth of corn plants under water stressed conditions.

Technical Abstract: Water availability is a major constraint affecting the growth and yield of agricultural crops worldwide. Some studies have shown that specific strains of free-living bacteria found in the plant rhizosphere can improve the tolerance of plants during water stress. A greenhouse study was conducted to evaluate the effects of two mixtures of plant growth-promoting rhizobacteria (PGPR) and two fertilizer sources on root establishment and biomass production of corn (Zea mays L.) during the early growth stages under drought conditions. Treatments included three irrigation levels (watering every 3, 6, and 12 days), two fertilizer materials (poultry litter and urea), and two PGPR strain mixtures and a non-inoculated control. Irrigation significantly affected plant growth and biomass accumulation of corn at the V6 to VT stages. Compared to poultry litter, urea application significantly increased plant height, leaf greennesschlorophyll (SPAD readings), leaf area, and plant biomass. PGPR significantly improved plant height, stem diameter, leaf greennesschlorophyll, and root morphology under drought stress conditions. The results demonstrate that PGPR inoculation can stimulate enhanced plant root development (through the production of plant growth regulators), thereby resulting in better absorption of water and nutrients from soil.