Chrysin alleviates salt stress by enhancing antioxidant enzymes, nutrient balance, and phytohormone contents in forage pea

This study aimed to evaluate the potential protective effects of chrysin (Chr), a flavonoid compound, on growth, biochemical,hormonal, and nutrient levels in forage pea (Pisum sativum ssp. arvense L.) seedlings under NaCl-induced salt stress. The experimentwas conducted under controlled greenhouse conditions in a completely randomized design with three different concentrations of Chr(Chr0: 0 mM, Chr1: 0.1 mM, and Chr2: 0.5 mM Chr) and three levels of salt stress (S0: 0 mM, S1: 100 mM, and S2: 200 mM NaCl),resulting in nine treatment combinations (T0: Chr0S0, T1: Chr0S1, T2: Chr0S2, T3: Chr1S0, T4: Chr1S1, T5: Chr1S2, T6: Chr2S0, T7: Chr2S1, andT8: Chr2S2).Salt stress reduced plant fresh weight by 73%, plant dry weight by 77%, root fresh weight by 70%, and root dry weight by 63%. Hydrogenperoxide (H2O2) levels increased by 480%, while malondialdehyde (MDA) levels increased by up to 627%. Growth hormones includingindole acetic acid (IAA) decreased by 73% and gibberellic acid (GA) by 69%, while abscisic acid (ABA) increased by 908%. Essentialnutrients nitrogen, phosphorus, and potassium decreased by 88%, 87%, and 88%, respectively.Chr applications significantly mitigated these adverse effects, with the 0.5 mM dose in particular enhancing growth parameters andantioxidant enzyme activities (catalase increased by 103%, peroxidase by 78%, and superoxide dismutase by 75%). Chr facilitatedthe accumulation of compatible solutes such as proline (902%) and sucrose (467%) while suppressing ABA levels by 68%. Regardingnutrient balance, nitrogen increased by 12%, potassium by 70%, and phosphorus by 160%.The findings indicate that Chr can serve as an effective protective agent against salt stress in sensitive species such as forage pea. Thisstudy highlights the potential of Chr in enhancing plant stress tolerance and provides a scientific basis for the use of flavonoid-basedbioregulators in agricultural stress management.