## 3 Results  
Given the results, the fraction of light absorbed by PSII that is used in photochemistry (\(P\)) increased by the fertilizer application in all non-stress, drought, and salinity conditions, while inversely, the fraction of absorbed light dissipated thermally, including the quantum yield of thermal dissipation in the dark-adapted state (\(L\)) and quantum yield of thermal dissipation in the light-adapted state (\(D\)), decreased or remained unchanged by the application of PGPB inoculation and chemical fertilization. The lowest and highest \(P\) values were determined in control (\(-\text{I}-\text{CF}\)) and PGPB inoculations combined with the half dose of chemical fertilizer (\(\text{I}+\frac{1}{2}\text{CF}\) treatment), respectively. This parameter ranged from 0.73, 0.66 and 0.66 in non-fertilized plants to 0.75, 0.71 and 0.73 in \(\text{I}+\frac{1}{2}\text{CF}\) treatment under non-stress, drought, and salinity conditions, respectively. In fact, PGPB inoculation, applied alone (I) \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Equation** & **Reference** \\ \hline Non-photochemical quenching (NPQ) & \(\text{NPQ}=\frac{\text{E}_{\text{n}}-\text{F}_{\text{n}}}{\text{F}_{\text{n}}}\) & [PERSON] [18] \\ Quantum yield of thermal dissipation in the DAS (\(L\)) & \(L=1-\frac{\text{E}_{\text{n}}}{\text{F}_{\text{n}}}\) & [PERSON] et al. [19] \\ Quantum yield of thermal dissipation in the LAS (\(D\)) & \(D=\frac{\text{F}_{\text{n}}}{\text{F}_{\text{n}}}-\frac{\text{F}_{\text{n}}}{ \text{F}_{\text{n}}}\) & [PERSON] et al. [19] \\ Fraction of light absorbed by PSII that is used in photochemistry (\(P\)) & \(P=\frac{\text{F}_{\text{n}}-\text{F}_{\text{0}}}{\text{F}_{\text{n}}}\times \frac{\text{F}_{\text{n}}-\text{F}_{\text{n}}}{\text{F}_{\text{n}}-\text{F}_{ \text{0}}}\) & [PERSON] et al. [20] \\ Complete non-photochemical quenching of ChlF (qCN) & \(\text{qCN}=\frac{\text{F}_{\text{v}}+\text{F}_{\text{n}}-\text{F}_{\text{n}}}{ \text{F}_{\text{n}}}\) & [PERSON] et al. [21] \\ Total quenching of variable ChIP (qTV) & \(\text{qTV}=1-\frac{\text{F}_{\text{n}}-\text{F}_{\text{0}}}{\text{F}_{\text{n}}- \text{F}_{\text{0}}}\) & [PERSON] et al. [22] \\ Total quenching of ChlF (qTQ) & \(\text{qTQ}=1-\frac{\text{F}_{\text{n}}^{\text{F}}}{\text{F}_{\text{n}}}\) & [PERSON] et al. [21] \\ Ratio of the quantum yield of actual PSII photochemistry in LAS to the quantum yield of the constitutive & \(\text{PQ}=\frac{\text{F}_{\text{n}}}{\text{F}_{\text{n}}}-\frac{\text{F}_{\text{n}}}{ \text{F}_{\text{n}}}\) & [PERSON] [17] \\ non-regulatory NPQ (PQ) & & \\ \hline ChlF: chlorophyll fluorescence; F\({}_{0}\), F\({}_{\text{n}}\) and F\({}_{\text{v}}\): Minimum, maximum and variable chlorophyll fluorescence yields in dark-adapted state; F\({}_{0}\)’, F\({}_{\text{m}}\)’ and F\({}_{\text{v}}\)’: Minimum, maximum and variable chlorophyll fluorescence yields in light-adapted state; F\({}_{\text{n}}\): Steady-state chlorophyll fluorescence yield in light-adapted state; DAS: Dark-adapted state; LAS: Light-adapted state; NPQ: Non-photochemical quenching. & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of commonly used concepts of chlorophyll fluorescence parameters referring to the quenching. or in combination with chemicals (I + \(\frac{1}{2}\)CF and I + CF), showed the same statistical significance level in terms of the \(P\) values, but were significantly greater than control treatment, not only in non-stress condition but also under drought and salinity (Table 2). On the other hand, \(D\) values in all experiments significantly decreased when PGPB inoculants were applied alone (I) or combined with the chemical fertilizers (I + \(\frac{1}{2}\)CF and I + CF) as compared to the control. This reduction for \(L\) parameter was significant only in salinity stress by application of I + \(\frac{1}{2}\)CF and I + CF treatments (Table 2).