Exogenously applied spermidine confers protection against cinnamic acid-mediated oxidative stress in Pisum sativum

Highlights • Cinnamic acid exposure reduced growth, pigment and protein contents but spermidine exposure attenuated the reduction. • The accumulation of osmolytes such as sugar and proline buttressed free radicals scavenging process. • Antioxidant metabolism was upregulated by the treatment of spermidine, thereby ameliorating cinnamic acid-induced oxidative damage.
This study investigated the stress responses of cinnamic acid (CA) in pea plants and explored the protective role of spermidine (SPD) against CA-induced adverse effects. Pea seedlings exposed to CA had reduced length, biomass, moisture, chlorophyll, sugar, and protein contents and reduced nitrate reductase activity. These parameters increased when SPD was applied alone and in combination with CA. Electrolyte leakage and malondialdehyde content were high in seedlings treated with CA but decreased when the SPD + CA treatment was applied. Foliar exposure to SPD partially mitigated CA-induced stress effects by strengthening the antioxidant defense system, which helped preserve the integrity of biochemical processes. These results indicate that SPD (1 mM) could mitigate the adverse effects of CA and enhance plant defense system. Hence, SPD can be used as a growth regulator for the maintenance of physiological functions in pea plants in response to the pernicious consequences of CA stress.