Inclusion of Ethylene Precursor into Priming Solution Improves Germination and Emergence of Narrow-leafed Purple Coneflower Seeds.

The effects of stratification and priming on germination and emergence performance of narrow-leafed purple coneflower (Echinacea angustifolia) seeds were investigated. Seeds were pre-chilled for 3 weeks at 4 ± 0.5 °C (39.2 ± 0.9 °F) in light or primed for 3 days at 20 ± 0.5 °C (68.0 ± 0.9 °F) in darkness in Nas and Read medium (NRM) or in 2% potassium nitrate (KNO₃) supplemented with 3 or 5 μM 1-aminocyclopropane carboxylic acid (ACC) or 500 mg·L^-1 (ppm) or 1000 mg·L^-1 gibberellic acid (GA₃). Following stratification and priming, seeds were subjected to germination and emergence tests at 25 ± 0.5 °C (77.0 ± 0.9 °F). Priming the seeds in NRM or KNO₃ containing 3 μM ACC gave the highest germination percentages with 78% and 80%, respectively. Stratification alone increased germination to 69% compared to nontreated seeds, which had the lowest germination percentage of 57%. Emergence was enhanced by priming seeds in the presence of 3 μM ACC (75%) compared to stratified seeds (62%), while nontreated seeds had the lowest emergence percentage of 26%. These results indicate that priming in the presence of ACC might be an alternative to lengthy stratification treatments to break the dormancy and improve the germination and emergence of narrow-leafed purple coneflower seeds. [ABSTRACT FROM AUTHOR]