: p-Coumaric acid (p-CA) belongs to a family of natural esters of hydroxycinnamic acid compounds that have been shown to modulate plant growth and metabolism. In this study, we investigated the effect of exogenous p-CA on plant growth, reactive oxygen species (ROS)-induced oxidative damage, photosynthetic metabolism, osmolyte content and changes in superoxide dismutase (SOD) enzymatic activity. Exogenous p-CA improved Salvia hispanica (chia) growth by significantly enhancing shoot length, fresh and dry weights coupled with augmented levels of total chlorophyll and carotenoid contents. Furthermore, p-CA also triggered an induction in proline, glycine betaine (GB) and superoxide (O2∙-) levels while no changes were observed for hydrogen peroxide (H2O2) and downstream malondialdehyde (MDA) content. Also, no change in SOD activity was observed in the p-CA treatment relative to the control. Therefore, the results suggest that exogenous p-CA improves chia seedling growth possibly via activation of a ROS-signalling pathway involving O2∙- under the control of proline accumulation.
Keywords: chia; chlorophyll content; osmoprotectants; oxidative stress; p-coumaric acid; proline; superoxide dismutase.