Potassium Hydroxide Improves Seed Germination and Emergence in Five Native Plant Species

Abstract

The seeds of difficult-to-germinate native species of American licorice ( Glycyrrhiza lepidota Pursh), angelica ( Angelica atropurpurea L.), wild blueberry ( Vaccinium angustifolium Ait.), wild mint ( Mentha arvensis L.), and purple coneflower ( Echinacea angustifolia D.C.), were soaked in 0, 2.5, 5.3, or 7.6 m KOH solutions for 0, 1, 5, 10, 15, or 20 minutes. After these treatments, germination was determined at 10 °C with a 14-hour photoperiod in petri dishes and seedling emergence was conducted at 14/10 °C with a 14-hour photoperiod in a sandy loam soil. In general, KOH treatment for only 1 min enhanced germination and seedling emergence. The optimal KOH concentration and soaking time in improving seed germination and seedling emergence varied with species, being 5.3 m and 10 min for purple coneflower, 5.3 m and 5 minutes for wild blueberry, 7.6 m and 5 minutes for angelica, 7.6 m and 1 minute for wild mint, and 5.3-7.6 m and 10 minutes for American licorice, respectively. Prolonged soaking, particularly in high concentrations, reduced germination and emergence.