Chemical Scarification, Moist Prechilling, and Thiourea Effects on Germination of 18 Shrub Species

Abstract

Establishment is a major problem of increasing palatable shrubs on rangeland; therefore the objective of this study was to determine the effects of chemical scarification, moist prechilling, and thiourea on seed germination in 18 different shrub species. Scarification for various periods in concentrated sulfuric acid, 10% hydrogen peroxide, and 5.25% sodium hypochlorite (clorox) produced unchanged or reduced germination, except for one hydrogen peroxide treatment of bitterbrush. Moist prechilling prior to germination was conducted on vermiculite moistened with distilled water or 0.2% potassium nitrate for periods up to 16 weeks. In general, prechilling yielded maximum germination, without respect to moistening agent. Seeds treated with thiourea were soaked for periods up to 1 hr in a 0.3% solution. Thiourea treatments were ineffective in increasing germination. On the basis of their germination response to prechilling treatments, bitterbrush, shadscale, big sagebrush, cliffrose, curlleaf mountain mahogany, and golden currant are recommended for fall planting. Apache plume, shrubby cinquefoil and Morman tea could be planted in spring or fall, and winterfat, fourwing saltbush, and Jersey tea should be planted in spring. Constraints other than seed germination, not studied here, must also be considered in planting shrubs for range improvement.