## 4 Discussion
According to [PERSON] [28], it is necessary to study interactions between selected strains to create possible consortia composed of various species of bacteria because the secondary metabolites or endotoxins produced by microbial strains in the consortium may adhere to the outer wall of the bacterial cell, and thus inhibit the growth and development of the other components of the inoculation consortium. The antagonistic interaction of bacterial strains in pure cultures may suggest a similar effect if such a consortium is created in the same environment with the plant. _Pseudomonas fluorescens_ secretes secondary metabolites, such as hydrocynanic acid and antibiotics, which are antagonistic to other microorganisms. The former has fungistatic properties, but it may also limit the growth of other bacteria [29]. A similar effect can be expected from the antibiotics secreted by these bacteria, such as 2,4-diacetylphloroglucinol and phenazine [30]. Laboratory experiments involving the coinoculation of legumes with endophytic bacteria and rhizobia [14; 24; 27; 28], which were conducted without the influence of additional biotic and abiotic factors, showed various effects of this treatment on the biometric parameters of the plants, i.e., the shoot length, the weight of the aboveground and belowground parts of the plants, the degree of root colonisation by bacteria, and the nitrogenase activity. In a study conducted by [PERSON] et al. [31], the coinoculation had either no influence or an antagonistic effect on the selected parameters of plants and the physiological activity of bacteria. On the other hand, studies conducted by [PERSON] et al. [32], [PERSON] and [PERSON] [24], and [PERSON] et al. [33] showed that coinoculation increased the length of the shoots of legumes, the weight of the aboveground and belowground parts of the plants, and the number of nodules. Our in vitro model experiment showed that the treatment of white lupine plants with selected bacterial strains of the _Bradyrhizobium_ sp. genus isolated from the Nitragina and Nitrofllora preparations as well as _Pseudomonas fluorescens_ and _Bacillus subtilis_ endophytic bacteria had a synergistic effect on the biometric parameters of the plants and the degree of root colonisation by the endophytic bacteria, as well as diazotrophy parameters (nitrogenase activity, the number and weight of nodules). It is important to note that the effects of inoculation and coinoculation were considerably diversified. The strongest mutualistic effect on the plant parameters was observed in the variants where the white lupine seeds had been coinoculated with bacteria of the _Bradyrhizobium_ genus isolated from the Nitrofllora preparation and the _Bacillus subtilis_ endophyte (variant nine). The coinoculation of the seeds with bacteria of the _Bradyrhizobium_genus isolated from the Nitroforora preparation and the _Pseudomonas fluorescens_ endophyte had a slightly weaker effect (variant eight). As a result of the coinoculation with the _Bradyrrizobium_ sp. isolates from the Nitragina preparation and _Pseudomonas fluorescens_, the length and weight of the aboveground parts of the plants were 6.6% and 4% lower, respectively, than the values of these parameters in the best variant nine (_Bradyrrizobium_ sp. from the Nitrofora preparation and _Bacillus subtilis_). Similar effects were observed for the diazotrophy parameters. Studies on legumes have shown that synergism between _Bacillus_ and _Bradyrrizobium_ bacteria in the rhizosphere increased the nodulation (the number and dry weight of nodules) and biomass of plants [34; 35; 36; 37; 38]. Some studies found that the coinoculation of legume seeds with bacteria of the _Pseudomonas_ sp. genus and _Rhizobium_ also improved the condition of the nodules [39]. There were also significant differences in the degree of white lupine root colonisation by the endophytes as well as in the coinoculation with the rhizobia isolated from the Nitroforora and Nitragina preparations.