Effect of Azospirillum spp. inoculation on root development and uptake in wheat (Triticum aestivum cv. Miriam) in hydroponic systems

Abstract

Wheat was grown in petri dishes and in vermiculite-filled pots. Inoculation with a mixture of A. brasilense strains Cd. Sp 7, and Cd-1, a local strain, significantly enhanced above noninoculated controls the root length and branching. In a hydroponic system containing NO3-, the surface area of roots and the uptake of NO3- from the mineral solution during plant growth were increased by inoculation. However, no significant changes were obtained in the NO3- uptake-root surface area ratio. Heading and flowering occurred earlier in the inoculated plants as compared with the noninoculated plants. Total shoot and root weights, plant height, the number of fertile tillers and grain yield were significantly increased by inoculation. The inoculated roots did not show any N fixation activity. Under these experimental conditions, the benefits obtained in wheat inoculated with Azospirillium are mainly derived from an enhancement of root development and the amount of NO3- taken up by the roots.