Karrikinolide stimulated seed germination of artificially aged marrow, cabbage and pepper seeds through repair of cell structure and enzyme activity.

• Priming with karrikinolide (KAR 1) enhanced seed germination in aged marrow, cabbage and pepper seeds. • Repair mechanism of seed aging by the treatments operated through repairing cell structure reducing solute leakage lower electrical conductivity and less K leakage in treated seeds. • Treatments with smoke extract affected ROS enzyme activity i.e. catalase, ascorbate peroxidase and superoxide dismutase activity of aged seeds. • Smoke extract treatments can be an efficient tool for enhancing seedling quality in marrow, cabbage and pepper seeds. The aging process induces the deterioration of seed vigor and viability. Priming methods have been shown to regenerate and rejuvenate aged crop seeds. Several studies have established that plant-derived smoke from burning plant material enhances germination and post-germination. Karrikinolide (KAR 1), which has been identified as a molecule derived from smoke, can improve the germination of seeds of a range of plant species. However, the effect of KAR 1 on aged seeds is not well known. Therefore, this study was carried out to determine the impact of KAR 1 and hydropriming on germination and repair mechanism in unaged and artificially aged pepper, marrow, and cabbage seeds. Aged seeds were artificially produced at 40 ± 1 °C and 100% relative humidity for 48 h in cabbage and 72 h in marrow and pepper. KAR 1 (10−7 M) was applied by dipping seeds in solution at a weight ratio of 1:5 seed: solution for 16 h at 20 °C. Hydropriming was applied under the same conditions using distilled water. Following the treatments, germination, seedling emergence, electrical conductivity, potassium leaching, and enzyme analysis were determined. Results showed that KAR 1- treated seeds had the lowest electrical conductivity and potassium leakage in unaged and artificially aged seeds in all three species. The influence of KAR 1 was more prominent on catalase activity in both artificially aged and unaged seeds. Additionally, KAR 1 treatment improved germination and fresh and dry weights of seedlings in all three species. The results of the present study show that the application of KAR 1 can help improve the performance of marrow, cabbage and pepper seeds in artificially aged (low-quality) seed germination. [ABSTRACT FROM AUTHOR]