Enhanced Germination of Echinacea angustifolia Seed with Ethephon and Sodium Hypochlortie Treatment

The influence of sodium hypochlorite and ethephon on the germination of narrow-leaved purple coneflower (Echinacea angustifolia) was investigated. Treatment of seeds with ethephon (1 mM) for 2 h followed by soaking in 0.525% sodium hypochlorite greatly increased germination (>90%). The treatment of seed with a combination of sodium hypochlorite and ethephon shortened number of days required to reach 50% of the final germination ($T_{50}$) from 4.2 days in control to 1.1 days. Seedlings grown from ethephon-treated seeds had shorter and thicker hypocotyls and roots with higher dry weights compared to the control. The same trend was observed during seedling emergence from soil. Ethephon treatment longer than 2 h resulted in weaker seedlings, probably due to leaf senescence. Anthocyanin content in seedling leaves increased linearly from 0.04 mg/g fresh weight in control to 3.72 mg/g fresh weight in 24 h treatment as the time of seed exposure to ethephon increased. Seed treatment with bleach and ethephon may well be practiced to facilitate the establishment of E. angustifolia in the field.