Effect of Azospirillum on coleoptile growth in wheat seedlings under water stress

One-cm-high Triticum aestivum cv. Buck Ombu seedlings were inoculated with ca. 10(8) cells Azospirillum brasilense Sp 245. After inoculation, seedlings were exposed to osmotic stress by immersing roots in 20 % polyethylene glycol (PEG) 8,000 (osmotic potential -0.60 MPa) up to 90 h. Germination and seedling growth were accomplished at 30 degrees C, in darkness. Seedlings inoculated with autoclaved bacteria were used as controls. Shoots were excised after 48 h and 90 h stress and growth parameters determined. Coleoptile height, fresh weight and dry weight were enhanced 79 %, 60 % and 54 % respectively, in wheat-inoculated seedlings after 90 h treatment. The effect of Azospirillum in promoting coleoptile growth in wheat seedlings under water stress and its possible implications on plant survival and grain yield, are discussed.