The Effect of Fermented Broth of Azospirillum spp.Wild and Mutatnt Types on In-vitro Propagation of Paulownia tomentosa

Abstract

Azospirillum spp. are considered to be important plant growth promotiverhizobacteria that can improve the growth and yield of several plant species. A collection of Azospirillum spp.isolates were isolated from different regions in Egypt. They were screened for their ability to produce phytohormones especially (IAA and cytokinins). Four isolates were selected depending on their capabilities in production of both IAA and cytokinins. The four isolates were identified depending on 16srDNA gene sequence. One isolate was selected for induction of mutations (K16) using physical mutagen (U.V. light), chemical mutagens (sodium azide). Five U.V. mutants and five sodium azide were selected and their capabilities in production of IAA and cytokinin were recorded. Filtrated fermented broth of two U.V. mutants (U.V.2 and U.V.4) and two sodium azide mutants (AZ3 and AZ4) were added in three concentrations (10, 20 and 40 ml/l MS) and the effect of this fermented broth on the in-vitro propagation of Paulownia tomentosa was studied. Results indicate that treatment with 40 ml/l MS fermented broth was the superior treatment followed by 20, and 10 ml/l MS respectively, fermented broth of U.V.4 (40 ml/l MS) was the best treatment in both root length and number of roots (2.03 and 12 respectively).