## 3 Discussion  
The Intergovernmental Panel on Climate Change (IPCC) report predicts a worldwide environmental change with alarming social, economic, and environmental consequences [1]. This will be particularly felt in coastal regions. Here, adverse effects of the temperature rise, expanding drought seasons, intensification of storm surges, and sea-level rises will be aggravated by intensive agricultural practices of the XXI century. Therefore, it can be presumed that water and soil salinization is one of the major worldwide plant stressors, and increasingly so [30]. Plant growth-promoting bacteria (PGPR) have been widely recognized to be a great tool for the augmentation of crop productivity and the improvement of the plant's stress coping ability [31; 32]. On the other hand, very little attention has been given to the enhancement of the innate tolerances found in the halophytes. The augmentation of the tolerance to excess salt is of great value considering the potential haloiderant _H. portulacoides_ have as a sea-water cash crop and in the bio-reclamation of salt-affected soils [33]. In this work, bioaugmentation was achieved by root inoculation using a consortium formed by competent salt marsh PGB-bacteria that were obtained and evaluated in a previous study [24]. The traits evaluated through the chlorophyll fluorescence measurements confirmed that _H. portulacoides_ is highly salt-tolerant, as expected from the findings in previous studies [34; 35]. However, at the highest tested concentration (600 mM NaCl) already some signs of stress could be found. Nevertheless, the most noticeable differences were detected when comparing the non-inoculated and inoculated plants' responses to the NaCl treatments. The photochemical analysis showed that the inoculated plants exhibited a substantial improvement in their photosystem II efficiency at mild salt stress. Inoculated _H. portulacoides_, at 400 mM NaCl, displayed higher trapped (TR/CS) and transport energy flux (ET/CS) per cross-section, the main flux responsible for chemical energy production, and available reaction centres (RC/CS) per cross-section. In addition, bioaugmentation significantly  
Figure 6: Leaves, (**A**) relative water content (RWC) and proline concentration (**B**) of non-inoculated and inoculated _Halimione portulacoides_ individuals (average \(\pm\) standard error, N = 5), along with the tested NaCl concentrations. Letters indicate significant differences between treatments at \(p<0.05\). increases the reaction centre II density within the PS II antenna. This could explain the greater energy translated at the electron transport chain, from quinone A to plastoquinone, suggesting a PGPR-induced improvement in the photon capture capability as well as a more efficient light-harvesting mechanism [36]. Plastoquinone functions are the primary electron acceptor of PS II [37]. Consequently, augmentation of plastoquinone activity plays a role in the significantly improved performance of the light reactions in primary photochemistry. This results in the observed enhancement of the overall equilibrium constant for the redox reactions between PS II and PS I [38; 39; 40; 41]. These features are reflected in the significant increase shown by the structural and functional index for photosynthesis (SFI) in the inoculated plants at 0 mM and 400 mM NaCl, and, as expected, a significantly lower non-photosynthetic or dissipation structure functional index (SFI\({}_{\text{NPQ}}\)) [42]. Additionally, the typical higher dissipation energy flux was observed in stressed individuals [43], and was also ameliorated in the plants inoculated with PGPB. These results revealed the PGPR consortium's significant enhancement of the photochemical performance of the plants at 0 mM NaCl but with a special impact at 400 mM NaCl. These differences found at the photosynthetic level can be explained, in part, by the influence exercised by the PGPR in the ionic uptake and osmotic regulation mechanisms.