Wood vinegar induces salinity tolerance by alleviating oxidative damages and protecting photosystem II in rapeseed cultivars

Wood vinegar (WV) is extensively used in agriculture in the form of organic fertilizer and antibacterial agent. WV is a liquid mixture of biologically active components that could improve growth and stress resilience in plants. However, its mechanism of action is still unknown. Therefore, a research experiment was designed to investigate the potential of WV application in conferring saline stress tolerance in rapeseed cultivars. The findings demonstrated that salt treatments considerably hindered plant growth, photosynthetic efficiency, and redox balance in rapeseed cultivars. However, pretreatment of WV at optimum concentration alleviated the salt induced inhibition of plant biomass production, chlorophyll and gas exchange parameters compared with salt stress treatments. The pretreatment of WV also reduced the oxidative stress, lipid peroxidation, improved antioxidant enzyme activities and proline accumulation in salt stressed plants. The observed recovery in WV pretreated rapeseed cultivars was associated with reduced uptake of Na+ and suppressed expression of salt transporter genes. Additionally, the reactive oxygen species (ROS) and photosynthetic inhibitors applications proved that key mechanisms of WV mediated salt stress mitigation in rapeseed cultivars, are related to the protection of photosynthetic machinery, reduction of ROS and regulation of stress responsive and ion channel genes. However, further studies are required on the underlying mechanisms of interaction between stress alleviation and wood vinegar mediated ion homeostasis in plants under salinity.