Presowing Seed Treatment and Temperature Effects on Germination of Engelmannia pinnatifida and Indigofera miniata var. leptosepala

Abstract

Research was conducted to evaluate the effects of presowing seed treatments and temperature on germination of seeds of Engelmann daisy (Engelmannia pinnatifida) and western indigo (Indigofera miniata var. leptosepala). The seeds were imbibed in controlled environmental conditions for 14 days with night/day temperatures of 5/15, 10/20, 15/25, or 20/30 degrees C and a 12-hour photoperiod corresponding with the high temperature. Seed treatments prior to imbibition included: mechanical scarification, immersion in hot water (80 degrees C) for 3 min., acid scarification by immersion in concentrated sulfuric acid for 17 min., and an untreated control. Percent germination was affected by both temperature and presowing seed treatments. Maximum germination (43%) of Engelmann daisy was attained by untreated seeds at 20/30 degrees C. Presowing seed treatments did not significantly increase germination of Engelmann daisy at any temperature. Western indigo seeds which were mechanically or acid scarified germinated over 90% in the 10/20, 15/25 and 20/30 degrees C temperature regimes. Seeds immersed in hot water germinated from 59-68%, and untreated seeds germinated from 17-42% in the same environmental conditions.