## 4 Discussion  
In the framework of this research, thermal dissipation associated with non-photochemical quenching, as an essential photo-protective mechanism of PSII [24], was investigated in durum wheat leaves under non-stress, drought, and salinity conditions, by comparing the application of a bacterial \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**PGPB** **Inoculation**} & \multirow{2}{*}{**Chemicals**} & **Plant Height** & **Root Weight** & **Chla + b** & **Chla/b** \\  & & & **(\(\pm\)SD)** & **(\(\pm\)SD)** & **(\(\pm\)SD)** & **(\(\pm\)SD)** \\ \cline{5-6}  & & & **cm** & **g/plant** & **\(\mu\)g cm\({}^{-2}\)** & \\ \hline \multirow{6}{*}{I} & \multirow{3}{*}{I} & \(-\)CF & 51.67 d (\(\pm\)0.03) & 0.34 c (\(\pm\)0.05) & 9.58 c (\(\pm\)0.79) & 2.37 a (\(\pm\)0.37) \\ \cline{3-6}  & & \(\frac{1}{2}\)CF & 55.33 cd (\(\pm\)6.22) & 0.39 b (\(\pm\)0.03) & 10.27 b (\(\pm\)1.10) & 2.84 a (\(\pm\)0.16) \\ \cline{3-6}  & & & 59.33 c (\(\pm\)5.61) & 0.36 bc (\(\pm\)0.05) & 11.17 ab (\(\pm\)0.94) & 2.47 a (\(\pm\)0.37) \\ \cline{3-6}  & & \(-\)CF & 64.67 ab (\(\pm\)7.31) & 0.41 ab (\(\pm\)0.05) & 10.32 b (\(\pm\)0.59) & 2.59 a (\(\pm\)0.44) \\ \cline{3-6}  & & \(\frac{1}{2}\)CF & 59.33 c (\(\pm\)5.50) & 0.44 a (\(\pm\)0.06) & 11.01 ab (\(\pm\)0.96) & 3.06 a (\(\pm\)0.48) \\ \cline{3-6}  & & & 68.67 a (\(\pm\)7.12) & 0.40 ab (\(\pm\)0.05) & 12.40 a (\(\pm\)1.07) & 2.46 a (\(\pm\)0.26) \\ \hline \hline \end{tabular}  
* Means in each column and each experiment followed by the same letter(s) are not significantly different based on the least significant difference (LSD) test at 0.05 probability level. +I: Seed inoculation with the selected PGPB consortium (bacterial suspension was also added to pots every 3 weeks); +I: No PGPB inoculation (durum wheat seeds were treated with non-inoculated NB medium before planting); CF: Soil treated with full dose of chemical fertilizer; \(\frac{1}{4}\)CF: Half dose of chemical fertilizer; \(-\)CF: No chemical fertilizer; Chla and \(b\): Chlorophyll \(a\) and \(b\); SD: Standard deviation.  
\end{table} 
Table 4: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Variable**} & \multicolumn{3}{c}{**r**} \\ \cline{2-4}  & **Non-Stress** & **Drought** & **Salinity** \\ \hline \(P\) & 0.42 * & 0.39 * & 0.47 * \\ \(L\) & \(-\)0.37 NS & \(-\)0.20 NS & \(-\)0.33 NS \\ \(D\) & \(-\)0.09 NS & \(-\)0.18 NS & \(-\)0.34 NS \\ NPQ & \(-\)0.24 NS & \(-\)0.08 NS & \(-\)0.43 * \\ qCN & \(-\)0.20 NS & 0.19 NS & \(-\)0.15 NS \\ qTV & 0.09 NS & 0.39 * & 0.39 * \\ qTQ & 0.41 * & 0.47 * & 0.40 * \\ PQ & 0.40 * & 0.44 * & 0.39 * \\ \hline \hline \end{tabular}  
*: Significant at \(p<0.05\) level; NS: Not Significant. \(P\): the fraction of light absorbed by PSII that is used in photochemistry; \(L\): Quantum yield of thermal dissipation in the dark-adapted state; \(D\): Quantum yield of thermal dissipation in the light-adapted state; NPQ: non-photochemical quenching coefficient; qCN: Complete non-photochemical quenching of ChFl; qTV: Total quenching of variable ChFl; qTQ: Total quenching of ChFl; PQ: Ratio of the quantum yield of actual PSII photochemistry in LAS to the quantum yield of the constitutive non-regulatory NPQ.  
\end{table} 
Table 5: Correlation coefficients (r) between grain yield and different fluorescence quenching parameters in response to the potentially beneficial bacterial (\(N=24\)). consortium composed of four PGPB strains (as bio-inoculants) to a traditional chemical fertilization plan. Research on simulation of the energy dissipation are based on two principle theories defined by [PERSON] et al. [20] that were drawn up on the basis of puddle model of energy transfer, in which the light energy absorbed in antennae chlorophyll is always transferred to the same reaction centers, and by [PERSON] et al. [25] and [PERSON] et al. [26] that made on the basis of the lake model of energy transfer, in which the excitation energy of chlorophylls can be exchanged among reaction centers.