Symbiotic activity of nodule bacteria in alfalfa crops

The North Caucasian Research Institute of Mountain and Piedmont Agriculture – the Affiliate of Vladikavkaz Scientific Centre of the Russian Academy of Sciences, village of Mikhailovskoye, st. Williams 1, 363110 North Ossetia-Alania, Russia

^* Corresponding author: geri4@list.ru

Abstract

A model association of legume-rhizobial symbiosis was obtained on a stamped callus culture of alfalfa roots when infected with Rhizobium meliloti. Using a culture aligned with the growth rate of strains, it was possible to obtain a reliable experimental model for studying the relationships of a legume plant with nodule bacteria. A regime has been worked out to obtain an effective imitation association of strain culture of callus tissues – fast-growing nodule bacteria on the example of infected with Rhizobium meliloti cells of callus tissues of alfalfa roots (Medicago sativa). The growth characteristics of the strain culture of the callus tissues of alfalfa roots were obtained: the most favorable period of infection of calluses with nodule bacteria was revealed; the optimal infectious load of nodule bacteria was selected – 5-7 rhizobia cells per 1 cell of alfalfa root callus; it was confirmed that incubation of associations on a medium containing a small amount of nitrogen and without kinetin contributes to the best manifestation of nitrogenase activity of associations. The act of introducing nodule bacteria of alfalfa into the cells of the tissue culture of its roots has been established. Bacteria were detected inside plant cells on the 7th day of infection of host plant tissues. The nitrogenase activity of the model systems increased with an increase in the incubation time of associations (from 1 to 4 days) on a medium without growth stimulants containing a small amount of nitrogen.