Wascharin Udchumpisai

The aim of this study was to assess the impact of pectic-oligosaccharides (POSs) obtained from oxidative degradation of pomelo peel with H₂O₂ under alkaline conditions on seed germination and growth of chili using the seed priming technique. Two types of POSs (POS-I and POS-II) with different size distributions were prepared. Chili seeds were soaked in 500 ppm of POS solutions for 16 h at two temperatures, 30 and 50 °C, with moderate shaking, and then air-dried. The primed seeds were planted on wet filter paper in a Petri dish at 30 °C for 9 d and the effects of priming on germination and growth were observed. Priming of seeds with POS at 30 °C increased the germination percentage and vigor index at 9 d after sowing by 16.7–20.5% and 16.0–25.5%, respectively, whereas root and shoot length did not differ from the hydropriming. However, there were no significant differences in all growth parameters between POS-I and POS-II treatments. Seedling length and the vigor index of seeds primed with POS at 30 °C (29.3–31.0 mm, 2693.9–2914.0) were also significantly higher than those of non-primed seeds (22.9 mm, 2062). Priming the seeds at 50 °C had an adverse effect on seed germination, i.e., the germination percentage was reduced by 24.4–31.9% compared to seeds primed at 30 °C. It also resulted in a significant reduction in chili seed growth, possibly due to the inactivation of some enzymes in chili seeds.