كليدواژه :
يونجه , تثبيت نيتروژن , كشاورزي , اگروباكتريوم
چكيده لاتين :
Many studies had been done on the microorganisms which were able to fix nitrogen recently. Agrobacterium has been added to this list. Agrobacterium belong to the family Rhizobiaceae. For study of the role of this bacterium in nirtogen fixation, the effects of this system on three different cultivars of Medicago namely Bami, Australian and American were investigated. In this study either mutate Sinorhizobium meliloti, which lack plasmid (nifH-nod+, nifK-) or carries plasmid nifHnod+(pSRk9) was used and compared with wild type and control. Analysis of variance showed that there was not any significant differences in height of those plants inoculated with nifH- when compared with control plant, but a significant increase in length was observed in plants inoculated with nifK-(PSRK9). The results showed that when plants were inoculated with sinorhizobium which contain nirtogen fixing system nifK-(PSRK9), the net production increased in all cultivars (based on dry weight). Sinorhizobium which carries plasmid, specially nifK-(SPRK9) had much higher number of active and large nodules which indicates nifK- is effective in nitrogen fixation. For determination of the quality of proteins which resulted from direct effects of nitrogen fixation in agrobacterium electrophoresis system was used The results indicated that there is not any differences in protein type. Sinorhzobium which carries plasmid of those lack plasmid but significant differences in total protein which accumulated in plants inoculated with different sinorhizobium was observed.
