POTASSIUM HYDROXIDE IMPROVES SEED-GERMINATION AND EMERGENCE IN 5 NATIVE PLANT-SPECIES

The seeds of difficult-to-germinate native species of American licoric e (Glycyrrhiza lepidota Pursh), angelica (Angelica atropurpurea L.), w ild blueberry (Vaccinium angustifolium Ait.), wild mint (Mentha arvens is L.), and purple coneflower (Echinacea angustifolia D.C.), were soak ed in 0, 2.5, 5.3, or 7.6 M KOH solutions for 0, 1, 5, 10, 15, or 20 m inutes. After these treatments, germination was determined at 10 degre es C with a 14-hour photoperiod in petri dishes and seedling emergence was conducted at 14/10 degrees C with a 14-hour photoperiod in a sand y loam soil. In general, KOH treatment for only 1 min enhanced germina tion 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 mi nutes 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 lico rice, respectively. Prolonged soaking, particularly in high concentrat ions, reduced germination and emergence.