## 3 Results
### Effects of PGPB on Canola Exposed to Saline Conditions
#### 3.3.4 Photosynthetic Pigments and Chlorophyll Fluorescence Parameters  
Leaf pigments such as chlorophylls and carotenoids can also be used as indicative parameters of stress when plants are cultivated under high salt concentrations. In our experiments, a significant increase in the amount of chlorophyll was detected, under saline soil conditions, in plants inoculated with _A. brasilense_, and _Pseudomonas_ sp., while plants inoculated with _B. ambifaria_ showed a significant decrease in this pigment. At the same time, a significant enhancement in chlorophyll content was found under non-saline soil conditions in plants inoculated with _A. brasilense_, _A. globiformis_, and _Pseudomonas_ sp., while plants inoculated with _H. serologicale_ highlighted a significant reduction in the photosynthetic pigment (Table 3). The carotenoids amount varies depending on the PGPB inoculated on canola plants. In particular, the amounts of carotenoids were significantly higher in plants grown under saline soil conditions and inoculated with _A. brasilense_, _B. ambifaria_, _H. serologicale_, and _Pseudomonas_ sp., compared with non-inoculated plants (Table 3). Moreover, a significant enhancement in carotenoid content was observed under non-saline soil conditions in plants inoculated with _A. globiformis_ and _Pseudomonas_ sp., (Table 3). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Total Chlorophylls (\(\underline{\mu}\)g/g f.w.)** & **Total Carotenoids (\(\underline{\mu}\)g/g f.w.)** \\ \hline N.I.C. & 265.73 \(\pm\) 5.02 a & 32.13 \(\pm\) 0.77 a \\ N.I.S. & 301.54 \(\pm\) 6.49 b & 37.81 \(\pm\) 0.79 b \\ A.C. & 315.13 \(\pm\) 17.98 a * & 34.72 \(\pm\) 2.1 a \\ A.S. & 414.42 \(\pm\) 22.07 b ** & 53.45 \(\pm\) 2.31 b ** \\ B.C. & 282.33 \(\pm\) 8.19 a & 35.59 \(\pm\) 1.5 a \\ B.S. & 221.82 \(\pm\) 15.70 b * & 42.25 \(\pm\) 1.31 b * \\ G.C. & 349.58 \(\pm\) 18.88 a * & 43.55 \(\pm\) 3.5 a * \\ G.S. & 322.53 \(\pm\) 15.01 a & 41.15 \(\pm\) 2.06 a \\ H.C. & 227.82 \(\pm\) 9.27 a * & 30.97 \(\pm\) 0.89 a \\ H.S. & 278.47 \(\pm\) 19.36 b & 44.69 \(\pm\) 2.96 b * \\ U. C & 379.51 \(\pm\) 49.4 a * & 51.51 \(\pm\) 5.7 a *** \\ U. S & 415.59 \(\pm\) 19.11 a ** & 51.43 \(\pm\) 2.47 a ** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Total chlorophyll and total carotenoid amounts of _B. napus_ cv. SY Savee grown for 30 days on non-saline soil (C) or saline soil (S). Plants were inoculated with plant growth-promoting bacteria (A = _A. brasilense_, B = _B. ambifaria_, G = _A. globiformis_, H = _H. serologicale_, U = _Pseudomonas_ sp. UW4) or not (N.I = non-inoculated). Different letter means significant difference within the same bacterial treatment. Significant differences between inoculated or non-inoculated plants grown at the same soil conditions are marked as * (_p_ < 0.05), ** (_p_ < 0.01) or *** (_p_ < 0.001) (_n_ = 9). Figure 5: APX activity of _B. napus_ grown in non-saline (C) and in saline soils (S). An analysis of chlorophyll fluorescence parameters (F\({}_{\rm v}\)/F\({}_{\rm m}\), \(\Phi\)PSII, NPQ, and ETR), and their associated images were utilized to provide information on the spatial heterogeneity of leaf photosynthetic performance in plants inoculated or not with the five PGPB strains. (Figure 6, Table 4). A representative image of chlorophyll fluorescence parameters (F\({}_{\rm v}\)/F\({}_{\rm m}\), \(\Phi\)PSII, and NPQ) in a single leaf in salt-stressed or not-stressed _B. napus_ plants inoculated or not with the five different PGPB is shown in Figure 6. In our experiments, a significant increase in F\({}_{\rm v}\)/F\({}_{\rm m}\) values was detected in plants inoculated with all the five PGPB strains (in saline soil) (Table 4). At the same time, a significant enhancement in \(\Phi\)PSII values was found in plants inoculated with _A. brasilense, B. ambigaria, A. globiformis, H. seropedicae_ (in saline soil). Moreover, the values of non-photochemical quenching (NPQ) showed a significant decrease in _B. napus_ plants grown in non-saline soil and inoculated with PGPB (except for _A.