|Suppression of root diseases and enhancement of VA mycorrhizal population in sunflower and tomato by the mycorrhizospheric fluorescent Pseudomonas |
S. EHTESHAMUL-HAQUE (1), S. S. Bokhari (2), S. A. Ali (3), V. Sultana (4), J. Ara (5). (1) Department of Botany, University of Karachi, Karachi, Pakistan; (2) Department of Botany, University of Karachi, Karachi, Pakistan; (3) HEJ Research Institute of Chemistry, University of Karachi, Karachi, Pakistan; (4) Department of Biochemistry, Univ
The vesicular arbuscular mycorrhizal (VAM) fungi, are obligate symbionts, improved uptake of nutrients by plants especially phosphorus. Several investigations have indicated that mycorrhizosphere bacteria may affect VAM fungi and their host plant. In this study, efficacy of some isolates of mycorrhizospheric fluorescent <i>Pseudomonas </i> (MRFP) that have shown significant activity against root rotting fungi (<i>Macrophomina phaseolina, Rhizoctonia solani, Fusarium solani, F.oxysporum</i>) and root knot nematode (<i>Meloidogyne javanica</i>)<i> in vitro </i>was evaluated in pots and in field plot experiments using sunflower and tomato as test plants. Most of the test MRFP showed significant biocontrol potential against soilborne pathogens by reducing the infection of root rotting fungi and gall formation by root knot nematode. The application of mycorrhizospheric fluorescent <i>Pseudomonas </i>significantly increased VAM population around the roots and in most of the cases showed better uptake of phosphorus by the plants. However, mixed application of VAM and fluorescent <i>Pseudomonas </i>did not show any added advantage. MRFP caused pronounced effect on sunflower by producing taller plants with greater fresh shoot weight both in screen house and field plot experiments. Fruit weight of tomato and flower weight of sunflower were also found significantly higher in most of the bacterized treatments as compared to control plants. .