Effects of GA₃ and PLGA-Controlled Release of GA₃ on the Germination of Caraway (Carum carvi L.)

Abstract

This study was conducted to evaluate the effects of gibberellic acid (GA₃) applied at different concentrations and its combination with PLGA (poly(lactic-co-glycolic acid)) controlled-release systems on the germination of Carum carvi L. seeds. The experiment was designed as a factorial trial in a completely randomized plot design using five treatments: control (distilled water), GA₃ at 150 and 300 mg/L, and GA₃ + PLGA combinations at 150 and 300 mg/L concentrations. Germination percentage (%), mean germination time (days), and germination index (speed) were analyzed. The results showed that GA₃ applied alone resulted in poor or no germination. In contrast, the combination of GA₃ with PLGA significantly improved both the germination rate and speed, providing more stable germination compared to the control group (P ≤ 0.05). Notably, the PLGA + 300 mg/L GA₃ treatment exhibited the highest performance, achieving a germination rate of 42.86% and a germination index of 5.01. No significant differences were observed between the control and PLGA + GA₃ treatments in terms of mean germination time. Moreover, while growth regression was observed in the control group after the 14th day, the PLGA + GA₃ treatments resulted in healthier and more sustained seedling development. These findings suggest that PLGA is an effective carrier for the controlled release of growth regulators such as GA₃ and can positively influence germination and early seedling development in medicinal and aromatic plants like Carum carvi L.