Gibberellic Acid Modulates the Changes Induced by Phenolic Compounds on the Germination and Seedling Growth in Cucumber (Cucumis sativus L.)

Phytohormones play critical a role in the plant growth and development and enhance the resistance to several stress situations. Phenolic compounds are some of the most widespread molecules among plant secondary metabolites, which inhibit seed germination and seedling growth in cucumber. With an objective to explore the possible ameliorators of inhibitory impact of phenolic compounds, cucumber (Cucumis sativus L.) cv. Long Green seeds exposed to 10⁻⁴ M each of catechol, gallic acid or pyrogallic acid were treated with 10⁻³ M of gibberellic acid (GA₃). Exposure of the seeds to the phenolic compounds significantly decreased the germination percentage, growth of radicle and hypocotyls and the fresh and dry weight of the seedlings. However, the follow up treatment with 10⁻³ M of GA₃ reversed the inhibitory impact of the phenolic compounds and there was a significant improvement in these parameters after GA₃ treatment. However, total phenolic content in the seedlings increased in response to phenolic compound treatments.