*2.8. E*ff*ects of GABA Priming on Detoxification-related Enzymes under Salinity, Osmotic Stress and OS*+*S*

The activities of the detoxification-related enzyme such as Glutathione-s-transferase (GST) and chitinase are shown in Figure 4B,C. Without stress, the GST activity in the primed seedlings was significantly lower than that in the control seedlings (Figure 4B). The GST activity was significantly increased by priming with 0.5 mM GABA under osmotic stress, salinity and OS+S as compared with unprimed seeds. Priming with GABA resulted in an increase in the GST activity under the osmotic stress, salinity and OS+S by 31.66%, 44.62% and 39.25%, respectively, relative to the controls (Figure 4B). Similarly, the chitinase activity was also increased under the osmotic stress, salinity and OS+S as compared to the unstressed condition (Figure 4C). There was no significant difference in the chitinase activity in the primed and unprimed seedlings under the unstressed condition. However, priming with 0.5 mM GABA increased the chitinase activity under the osmotic stress, salinity and OS+S, by 15.54%, 28.34% and 42.09%, respectively, relative to the controls (Figure 4C).
