Enhancing Germination of Spiny Hackberry Seeds

Abstract

Establishment of spiny hackberry (Celtis pallida Torr.) in plantings for wildlife has been hampered by low seed germination. We evaluated methods for enhancing germination of spiny hackberry by subjecting seeds to: (1) chemical scarification with 2.9 mol liter-1 H2O2, 0.71 mol liter-1 NaOCl, and concentrated (18 mol liter-1) H2 SO4; (2) rinsing with water; (3) 0, 0.3, 1.4, 2.9, and 4.3 mmol liter-1 gibberellic acid (GA); (4) 0.02 mol liter-1 KNO3; (5) mechanical scarification, or (6) moist heat (30 degrees C) followed by moist prechilling at 7 degrees C for 2 weeks. Untreated seeds exhibited higher percent germination in the light than in the dark. Percentage germination at 30 degrees C and germination rate were increased in the light and in the dark by either 1.4 mmol liter-1 GA or 3 days of moist heat (30 degrees C) followed by a 2-week moist prechill at 7 degrees C. A combination of mechanical scarification + 1.4 mmol liter-1 GA + 3 days moist heat (30 degrees C) followed by moist prechilling for 2 weeks at 7 degrees C increased germination from 1% (controls) to 49%. Germination varied slightly with seed source, but a large proportion of all lots was dormant. Spiny hackberry seeds can be treated with a combination of mechanical scarification + 1.4 mmol liter-1 GA + 3 days moist heat (30 degrees C) followed by moist prechilling for 2 weeks at 7 degrees C before planting to increase percentage and rate of germination.