Archive | 2021
Involvement of Ethylene in Reversal of Salt Stress by Salicylic acid in Presence of Sulfur in Mustard (Brassica juncea L.)
Abstract
\n The involvement of ethylene in reversal of salt stress inhibited photosynthetic activity and growth by salicylic acid (SA) together with sulfur (S) was studied in mustard (Brassica juncea L.) plants. Application of SA (0.5 mM) plus SO42- (2.0 mM) improved photosynthetic activity through markedly increased S-assimilation, antioxidant enzymes activity and optimized ethylene and glutathione (GSH) production for reduced reactive oxygen species (ROS) in plants under 50 mM NaCl stress. As SA acts as an inhibitor of ethylene, and S-assimilation is associated with ethylene synthesis, we tried to figure out the interaction of ethylene in SA and SO42- mediated salt tolerance. The involvement of ethylene was studied by supplementing salt treated plants with 200 µL L-1 ethephon (an ethylene-releasing compound) or 100 µM norbornadiene (NBD, ethylene action inhibitor) to SA and SO42- treatments. The ethephon application to salt treated plants suppressed stress ethylene and optimized ethylene formation and increased ethylene sensitivity to enhance photosynthesis of plants by affecting antioxidative capacity of plants. Application of NBD to plants receiving SA plus SO42- in presence of salt showed inhibited photosynthetic characteristics, stomatal behavior and growth. These plants exhibited minimal capacity of S-assimilation and antioxidant enzymes activity and GSH content. This explained that ethylene was involved in the reversal of salt stress by SA plus SO42-. Thus, the study showed that ethylene intervenes the effect of SA in the presence of SO42- to upregulate the antioxidants that lead to increased S-assimilation, and imparted tolerance to salt in mustard plants.