Hydrogen peroxide seed scarification of New Mexico collections of ribes cereum

Abstract

Ribes cereum is an early-colonizing shrub species being evaluated for disturbed-land revegetation in New Mexico. Along with embryo dormancy, seed coat dormancy is thought to occur in this species, but acid scarification has failed to improve germination consistently. To examine the efficacy ofscarification using hydrogen peroxide, seeds from six R. cereum collections from throughout New Mexico were soaked in 3% hydrogen peroxide for 0, 4, 8, or 16 hours and then stratified for 0,60,90 or 120 days. For all collections, a four-hour soak improved germination. The combination of a four-hour hydrogen peroxide soak followed by 120 days of stratification was the optimal treatment combination for most collections. With the exception of the southernmost collection, stratification was more effective than hydrogen peroxide scarification in promoting R. cereum germination. For this small-seeded species, a four-hour soak in 3% peroxide effectively degrades seed coat tissues without causing embryo damage. The choice between sulfuric acid and hydrogen peroxide as chemical scarification agent is discussed in terms seed size, seed coat thickness and seed susceptibility to damage.